diff --git a/.ci/bwcVersions b/.ci/bwcVersions
index 0600d2f3537c7..aa12cf1020510 100644
--- a/.ci/bwcVersions
+++ b/.ci/bwcVersions
@@ -13,4 +13,5 @@ BWC_VERSION:
   - "2.4.1"
   - "2.4.2"
   - "2.5.0"
+  - "2.5.1"
   - "2.6.0"
diff --git a/.github/ISSUE_TEMPLATE/failed_check.md b/.github/ISSUE_TEMPLATE/failed_check.md
new file mode 100644
index 0000000000000..86d90c2fd0efd
--- /dev/null
+++ b/.github/ISSUE_TEMPLATE/failed_check.md
@@ -0,0 +1,9 @@
+---
+title: Gradle Check Failure.
+labels: >test-failure bug
+---
+
+A gradle check workflow has failed after merge.
+
+PR: {{ env.workflow_url }}
+CommitId: {{ env.pr_from_sha }}
diff --git a/.github/workflows/backport.yml b/.github/workflows/backport.yml
index 5a75d2c877992..2b95fb2510bdd 100644
--- a/.github/workflows/backport.yml
+++ b/.github/workflows/backport.yml
@@ -7,12 +7,22 @@ on:
 
 jobs:
   backport:
-    if: ${{ contains(github.event.label.name, 'backport') }}
+    name: Backport
     runs-on: ubuntu-latest
+    # Only react to merged PRs for security reasons.
+    # See https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#pull_request_target.
+    if: >
+      github.event.pull_request.merged
+      && (
+        github.event.action == 'closed'
+        || (
+          github.event.action == 'labeled'
+          && contains(github.event.label.name, 'backport')
+        )
+      )
     permissions:
       contents: write
       pull-requests: write
-    name: Backport
     steps:
       - name: GitHub App token
         id: github_app_token
diff --git a/.github/workflows/dependabot_pr.yml b/.github/workflows/dependabot_pr.yml
index ed98bae8978ed..a2ad70709f51a 100644
--- a/.github/workflows/dependabot_pr.yml
+++ b/.github/workflows/dependabot_pr.yml
@@ -51,7 +51,7 @@ jobs:
       - name: Update the changelog
         uses: dangoslen/dependabot-changelog-helper@v1
         with:
-          version: 'Unreleased'
+          version: 'Unreleased 3.0'
 
       - name: Commit the changes
         uses: stefanzweifel/git-auto-commit-action@v4
diff --git a/.github/workflows/gradle-check.yml b/.github/workflows/gradle-check.yml
index 9567bcd63bc2e..2cfcfa8d9d1f9 100644
--- a/.github/workflows/gradle-check.yml
+++ b/.github/workflows/gradle-check.yml
@@ -16,6 +16,7 @@ jobs:
     permissions:
       contents: read # to fetch code (actions/checkout)
       pull-requests: write # to create or update comment (peter-evans/create-or-update-comment)
+      issues: write # To create an issue if check fails on push.
 
     runs-on: ubuntu-latest
     timeout-minutes: 130
@@ -123,3 +124,12 @@ jobs:
               * **CommitID:** ${{ env.pr_from_sha }}
               Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green.
               Is the failure [a flaky test](https://github.com/opensearch-project/OpenSearch/blob/main/DEVELOPER_GUIDE.md#flaky-tests) unrelated to your change?
+
+      - name: Create Issue On Push Failure
+        if: ${{ github.event_name == 'push' && failure() }}
+        uses: dblock/create-a-github-issue@v3
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          assignees: ${{ github.event.head_commit.author.username }}, ${{ github.triggering_actor }}
+          filename: .github/ISSUE_TEMPLATE/failed_check.md
diff --git a/.gitignore b/.gitignore
index a0dabfb8798f9..9ab7de894636a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -13,8 +13,10 @@ out/
 !.idea/vcs.xml
 !.idea/icon.svg
 
-# These files are generated in the main tree by IntelliJ
+# These files are generated in the main tree by annotation processors
 benchmarks/src/main/generated/*
+benchmarks/bin/*
+benchmarks/build-eclipse-default/*
 
 # eclipse files
 .project
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2f9075b6a4ed3..2add4f68b884a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,46 +1,27 @@
-
 # CHANGELOG
-## [Unreleased]
-### Dependencies
-- Bumps `azure-core-http-netty` from 1.12.7 to 1.12.8
-- Bumps `reactor-netty` from 1.1.1 to 1.1.2
-
-
 All notable changes to this project are documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/), and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html). See the [CONTRIBUTING guide](./CONTRIBUTING.md#Changelog) for instructions on how to add changelog entries.
 
 ## [Unreleased 3.0]
 ### Added
-- Add support of default replica count cluster setting ([#5610](https://github.com/opensearch-project/OpenSearch/pull/5610))
 - Hardened token permissions in GitHub workflows ([#4587](https://github.com/opensearch-project/OpenSearch/pull/4587))
 - Support for HTTP/2 (server-side) ([#3847](https://github.com/opensearch-project/OpenSearch/pull/3847))
 - Add getter for path field in NestedQueryBuilder ([#4636](https://github.com/opensearch-project/OpenSearch/pull/4636))
-- Apply reproducible builds configuration for OpenSearch plugins through gradle plugin ([#4746](https://github.com/opensearch-project/OpenSearch/pull/4746))
-- Add project health badges to the README.md ([#4843](https://github.com/opensearch-project/OpenSearch/pull/4843))
-- [Test] Add IAE test for deprecated edgeNGram analyzer name ([#5040](https://github.com/opensearch-project/OpenSearch/pull/5040))
 - Allow mmap to use new JDK-19 preview APIs in Apache Lucene 9.4+ ([#5151](https://github.com/opensearch-project/OpenSearch/pull/5151))
-- Add feature flag for extensions ([#5211](https://github.com/opensearch-project/OpenSearch/pull/5211))
-- Support to fail open requests on search shard failures with weighted traffic routing ([#5072](https://github.com/opensearch-project/OpenSearch/pull/5072))
-- Added jackson dependency to server ([#5366] (https://github.com/opensearch-project/OpenSearch/pull/5366))
-- Adding support to register settings dynamically ([#5495](https://github.com/opensearch-project/OpenSearch/pull/5495))
-- Added experimental support for extensions ([#5347](https://github.com/opensearch-project/OpenSearch/pull/5347)), ([#5518](https://github.com/opensearch-project/OpenSearch/pull/5518), ([#5597](https://github.com/opensearch-project/OpenSearch/pull/5597)), ([#5615](https://github.com/opensearch-project/OpenSearch/pull/5615)))
-- Add CI bundle pattern to distribution download ([#5348](https://github.com/opensearch-project/OpenSearch/pull/5348))
 - Add support for ppc64le architecture ([#5459](https://github.com/opensearch-project/OpenSearch/pull/5459))
-- Support versioning for Weighted routing apis([#5255](https://github.com/opensearch-project/OpenSearch/pull/5255))
-- Added @gbbafna as an OpenSearch maintainer ([#5668](https://github.com/opensearch-project/OpenSearch/pull/5668))
-- Add support for discovered cluster manager and remove local weights ([#5680](https://github.com/opensearch-project/OpenSearch/pull/5680))
-- Added support for feature flags in opensearch.yml ([#4959](https://github.com/opensearch-project/OpenSearch/pull/4959))
-- Add query for initialized extensions ([#5658](https://github.com/opensearch-project/OpenSearch/pull/5658))
-- Revert 'Added jackson dependency to server' and change extension reading ([#5768](https://github.com/opensearch-project/OpenSearch/pull/5768))
 - Add support to disallow search request with preference parameter with strict weighted shard routing([#5874](https://github.com/opensearch-project/OpenSearch/pull/5874))
+- Replace latches with CompletableFutures for extensions ([#5646](https://github.com/opensearch-project/OpenSearch/pull/5646))
+### Dependencies
+- Bumps `wiremock-jre8-standalone` from 2.33.2 to 2.35.0
+- Bumps `gson` from 2.10 to 2.10.1
+- Bumps `json-schema-validator` from 1.0.73 to 1.0.76
 
 ### Dependencies
 - Bumps `log4j-core` from 2.18.0 to 2.19.0
 - Bumps `reactor-netty-http` from 1.0.18 to 1.0.23
 - Bumps `jettison` from 1.5.0 to 1.5.3
 - Bumps `forbiddenapis` from 3.3 to 3.4
-- Bumps `gson` from 2.9.0 to 2.10
 - Bumps `avro` from 1.11.0 to 1.11.1
 - Bumps `woodstox-core` from 6.3.0 to 6.3.1
 - Bumps `xmlbeans` from 5.1.0 to 5.1.1 ([#4354](https://github.com/opensearch-project/OpenSearch/pull/4354))
@@ -51,32 +32,21 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Bumps `com.diffplug.spotless` from 6.10.0 to 6.11.0 ([#4547](https://github.com/opensearch-project/OpenSearch/pull/4547))
 - Bumps `reactor-core` from 3.4.23 to 3.5.1 ([#5604](https://github.com/opensearch-project/OpenSearch/pull/5604))
 - Bumps `jempbox` from 1.8.16 to 1.8.17 ([#4550](https://github.com/opensearch-project/OpenSearch/pull/4550))
-- Bumps `commons-compress` from 1.21 to 1.22
-- Bumps `jcodings` from 1.0.57 to 1.0.58 ([#5233](https://github.com/opensearch-project/OpenSearch/pull/5233))
-- Bumps `google-http-client-jackson2` from 1.35.0 to 1.42.3 ([#5234](https://github.com/opensearch-project/OpenSearch/pull/5234))
-- Bumps `azure-core` from 1.33.0 to 1.34.0 ([#5235](https://github.com/opensearch-project/OpenSearch/pull/5235))
-- Bumps `azure-core-http-netty` from 1.12.4 to 1.12.7 ([#5235](https://github.com/opensearch-project/OpenSearch/pull/5235))
 - Bumps `spock-core` from 2.1-groovy-3.0 to 2.3-groovy-3.0 ([#5315](https://github.com/opensearch-project/OpenSearch/pull/5315))
-- Bumps `json-schema-validator` from 1.0.69 to 1.0.73 ([#5316](https://github.com/opensearch-project/OpenSearch/pull/5316))
-- Bumps `proto-google-common-protos` from 2.8.0 to 2.10.0 ([#5318](https://github.com/opensearch-project/OpenSearch/pull/5318))
 - Update to Gradle 7.6 and JDK-19 ([#4973](https://github.com/opensearch-project/OpenSearch/pull/4973))
 - Update Apache Lucene to 9.5.0-snapshot-d5cef1c ([#5570](https://github.com/opensearch-project/OpenSearch/pull/5570))
 - Bump antlr4 from 4.9.3 to 4.11.1 ([#4546](https://github.com/opensearch-project/OpenSearch/pull/4546))
 - Bumps `maven-model` from 3.6.2 to 3.8.6 ([#5599](https://github.com/opensearch-project/OpenSearch/pull/5599))
 - Bumps `maxmind-db` from 2.1.0 to 3.0.0 ([#5601](https://github.com/opensearch-project/OpenSearch/pull/5601))
 - Bumps `protobuf-java` from 3.21.11 to 3.21.12 ([#5603](https://github.com/opensearch-project/OpenSearch/pull/5603))
-- Update nebula-publishing-plugin to 19.2.0 ([#5704](https://github.com/opensearch-project/OpenSearch/pull/5704))
+- Bumps `azure-core-http-netty` from 1.12.7 to 1.12.8
 
 ### Changed
 - [CCR] Add getHistoryOperationsFromTranslog method to fetch the history snapshot from translogs ([#3948](https://github.com/opensearch-project/OpenSearch/pull/3948))
 - Relax visibility of the HTTP_CHANNEL_KEY and HTTP_SERVER_CHANNEL_KEY to make it possible for the plugins to access associated Netty4HttpChannel / Netty4HttpServerChannel instance ([#4638](https://github.com/opensearch-project/OpenSearch/pull/4638))
-- Use ReplicationFailedException instead of OpensearchException in ReplicationTarget ([#4725](https://github.com/opensearch-project/OpenSearch/pull/4725))
 - Migrate client transports to Apache HttpClient / Core 5.x ([#4459](https://github.com/opensearch-project/OpenSearch/pull/4459))
-- Support remote translog transfer for request level durability([#4480](https://github.com/opensearch-project/OpenSearch/pull/4480))
 - Changed http code on create index API with bad input raising NotXContentException from 500 to 400 ([#4773](https://github.com/opensearch-project/OpenSearch/pull/4773))
 - Change http code for DecommissioningFailedException from 500 to 400 ([#5283](https://github.com/opensearch-project/OpenSearch/pull/5283))
-- Pre conditions check before updating weighted routing metadata ([#4955](https://github.com/opensearch-project/OpenSearch/pull/4955))
-- Gracefully handle concurrent zone decommission action ([#5542](https://github.com/opensearch-project/OpenSearch/pull/5542))
 
 ### Deprecated
 
@@ -98,29 +68,34 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 ### Fixed
 - Fix 'org.apache.hc.core5.http.ParseException: Invalid protocol version' under JDK 16+ ([#4827](https://github.com/opensearch-project/OpenSearch/pull/4827))
 - Fixed compression support for h2c protocol ([#4944](https://github.com/opensearch-project/OpenSearch/pull/4944))
-- Reject bulk requests with invalid actions ([#5299](https://github.com/opensearch-project/OpenSearch/issues/5299))
 - Support OpenSSL Provider with default Netty allocator ([#5460](https://github.com/opensearch-project/OpenSearch/pull/5460))
-- Increasing timeout of testQuorumRecovery to 90 seconds from 30 ([#5651](https://github.com/opensearch-project/OpenSearch/pull/5651))
-- [Segment Replication] Fix for peer recovery ([#5344](https://github.com/opensearch-project/OpenSearch/pull/5344))
-- [Test] Renaming PIT tests to IT to fix intermittent test failures ([#5750](https://github.com/opensearch-project/OpenSearch/pull/5750))
 
 ### Security
 
 ## [Unreleased 2.x]
 ### Added
+- Adding index create block when all nodes have breached high disk watermark ([#5852](https://github.com/opensearch-project/OpenSearch/pull/5852))
 - Added cluster manager throttling stats in nodes/stats API ([#5790](https://github.com/opensearch-project/OpenSearch/pull/5790))
+- Added support for feature flags in opensearch.yml ([#4959](https://github.com/opensearch-project/OpenSearch/pull/4959))
+- Add query for initialized extensions ([#5658](https://github.com/opensearch-project/OpenSearch/pull/5658))
+- Add update-index-settings allowlist for searchable snapshot ([#5907](https://github.com/opensearch-project/OpenSearch/pull/5907))
 
 ### Dependencies
+- Update nebula-publishing-plugin to 19.2.0 ([#5704](https://github.com/opensearch-project/OpenSearch/pull/5704))
+- Bumps `reactor-netty` from 1.1.1 to 1.1.2
 
 ### Changed
+- Use ReplicationFailedException instead of OpensearchException in ReplicationTarget ([#4725](https://github.com/opensearch-project/OpenSearch/pull/4725))
+- [Refactor] Use local opensearch.common.SetOnce instead of lucene's utility class ([#5947](https://github.com/opensearch-project/OpenSearch/pull/5947))
 
 ### Deprecated
 
 ### Removed
 
 ### Fixed
+- [Segment Replication] Fix for peer recovery ([#5344](https://github.com/opensearch-project/OpenSearch/pull/5344))
 
 ### Security
 
-[Unreleased 3.0]: https://github.com/opensearch-project/OpenSearch/compare/2.4...HEAD
-[Unreleased 2.x]: https://github.com/opensearch-project/OpenSearch/compare/2.4...2.x
+[Unreleased 3.0]: https://github.com/opensearch-project/OpenSearch/compare/2.x...HEAD
+[Unreleased 2.x]: https://github.com/opensearch-project/OpenSearch/compare/2.5...2.x
\ No newline at end of file
diff --git a/buildSrc/build.gradle b/buildSrc/build.gradle
index 129f60378b47e..58849bb637429 100644
--- a/buildSrc/build.gradle
+++ b/buildSrc/build.gradle
@@ -118,14 +118,14 @@ dependencies {
   api 'com.avast.gradle:gradle-docker-compose-plugin:0.15.2'
   api "org.yaml:snakeyaml:${props.getProperty('snakeyaml')}"
   api 'org.apache.maven:maven-model:3.8.6'
-  api 'com.networknt:json-schema-validator:1.0.73'
+  api 'com.networknt:json-schema-validator:1.0.76'
   api "com.fasterxml.jackson.core:jackson-databind:${props.getProperty('jackson_databind')}"
 
   testFixturesApi "junit:junit:${props.getProperty('junit')}"
   testFixturesApi "com.carrotsearch.randomizedtesting:randomizedtesting-runner:${props.getProperty('randomizedrunner')}"
   testFixturesApi gradleApi()
   testFixturesApi gradleTestKit()
-  testImplementation 'com.github.tomakehurst:wiremock-jre8-standalone:2.33.2'
+  testImplementation 'com.github.tomakehurst:wiremock-jre8-standalone:2.35.0'
   testImplementation "org.mockito:mockito-core:${props.getProperty('mockito')}"
   integTestImplementation('org.spockframework:spock-core:2.3-groovy-3.0') {
     exclude module: "groovy"
diff --git a/buildSrc/src/main/resources/forbidden/opensearch-all-signatures.txt b/buildSrc/src/main/resources/forbidden/opensearch-all-signatures.txt
index 1e4e669e4722f..f9f24fd1e2367 100644
--- a/buildSrc/src/main/resources/forbidden/opensearch-all-signatures.txt
+++ b/buildSrc/src/main/resources/forbidden/opensearch-all-signatures.txt
@@ -50,6 +50,7 @@ java.nio.channels.SocketChannel#connect(java.net.SocketAddress)
 java.lang.Boolean#getBoolean(java.lang.String)
 
 org.apache.lucene.util.IOUtils @ use @org.opensearch.core.internal.io instead
+org.apache.lucene.util.SetOnce @ use @org.opensearch.common.SetOnce instead
 
 @defaultMessage use executors from org.opensearch.common.util.concurrent.OpenSearchExecutors instead which will properly bubble up Errors
 java.util.concurrent.AbstractExecutorService#<init>()
diff --git a/libs/core/src/main/java/org/opensearch/common/SetOnce.java b/libs/core/src/main/java/org/opensearch/common/SetOnce.java
new file mode 100644
index 0000000000000..a596b5fcdb61d
--- /dev/null
+++ b/libs/core/src/main/java/org/opensearch/common/SetOnce.java
@@ -0,0 +1,104 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+package org.opensearch.common;
+
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * A convenient class which offers a semi-immutable object wrapper implementation which allows one
+ * to set the value of an object exactly once, and retrieve it many times. If {@link #set(Object)}
+ * is called more than once, {@link AlreadySetException} is thrown and the operation will fail.
+ *
+ * This is borrowed from lucene's experimental API. It is not reused to eliminate the dependency
+ * on lucene core for such a simple (standalone) utility class that may change beyond OpenSearch needs.
+ *
+ * @opensearch.api
+ */
+public final class SetOnce<T> implements Cloneable {
+
+    /** Thrown when {@link SetOnce#set(Object)} is called more than once. */
+    public static final class AlreadySetException extends IllegalStateException {
+        public AlreadySetException() {
+            super("The object cannot be set twice!");
+        }
+    }
+
+    /** Holding object and marking that it was already set */
+    private static final class Wrapper<T> {
+        private T object;
+
+        private Wrapper(T object) {
+            this.object = object;
+        }
+    }
+
+    private final AtomicReference<Wrapper<T>> set;
+
+    /**
+     * A default constructor which does not set the internal object, and allows setting it by calling
+     * {@link #set(Object)}.
+     */
+    public SetOnce() {
+        set = new AtomicReference<>();
+    }
+
+    /**
+     * Creates a new instance with the internal object set to the given object. Note that any calls to
+     * {@link #set(Object)} afterwards will result in {@link AlreadySetException}
+     *
+     * @throws AlreadySetException if called more than once
+     * @see #set(Object)
+     */
+    public SetOnce(T obj) {
+        set = new AtomicReference<>(new Wrapper<>(obj));
+    }
+
+    /** Sets the given object. If the object has already been set, an exception is thrown. */
+    public final void set(T obj) {
+        if (!trySet(obj)) {
+            throw new AlreadySetException();
+        }
+    }
+
+    /**
+     * Sets the given object if none was set before.
+     *
+     * @return true if object was set successfully, false otherwise
+     */
+    public final boolean trySet(T obj) {
+        return set.compareAndSet(null, new Wrapper<>(obj));
+    }
+
+    /** Returns the object set by {@link #set(Object)}. */
+    public final T get() {
+        Wrapper<T> wrapper = set.get();
+        return wrapper == null ? null : wrapper.object;
+    }
+}
diff --git a/libs/core/src/test/java/org/opensearch/common/SetOnceTests.java b/libs/core/src/test/java/org/opensearch/common/SetOnceTests.java
new file mode 100644
index 0000000000000..0392ff62dd115
--- /dev/null
+++ b/libs/core/src/test/java/org/opensearch/common/SetOnceTests.java
@@ -0,0 +1,120 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.common;
+
+import org.opensearch.common.SetOnce.AlreadySetException;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.Random;
+
+import static org.hamcrest.CoreMatchers.containsString;
+
+public class SetOnceTests extends OpenSearchTestCase {
+    private static final class SetOnceThread extends Thread {
+        SetOnce<Integer> set;
+        boolean success = false;
+        final Random RAND;
+
+        public SetOnceThread(Random random) {
+            RAND = new Random(random.nextLong());
+        }
+
+        @Override
+        public void run() {
+            try {
+                sleep(RAND.nextInt(10)); // sleep for a short time
+                set.set(Integer.valueOf(getName().substring(2)));
+                success = true;
+            } catch (@SuppressWarnings("unused") InterruptedException e) {
+                // ignore
+            } catch (@SuppressWarnings("unused") RuntimeException e) {
+                // TODO: change exception type
+                // expected.
+                success = false;
+            }
+        }
+    }
+
+    public void testEmptyCtor() {
+        SetOnce<Integer> set = new SetOnce<>();
+        assertNull(set.get());
+    }
+
+    public void testSettingCtor() {
+        SetOnce<Integer> set = new SetOnce<>(5);
+        assertEquals(5, set.get().intValue());
+
+        AlreadySetException alreadySetException = expectThrows(AlreadySetException.class, () -> set.set(7));
+        assertThat(alreadySetException.getMessage(), containsString("The object cannot be set twice!"));
+    }
+
+    public void testSetOnce() {
+        SetOnce<Integer> set = new SetOnce<>();
+        set.set(5);
+        assertEquals(5, set.get().intValue());
+
+        AlreadySetException alreadySetException = expectThrows(AlreadySetException.class, () -> set.set(7));
+        assertThat(alreadySetException.getMessage(), containsString("The object cannot be set twice!"));
+    }
+
+    public void testTrySet() {
+        SetOnce<Integer> set = new SetOnce<>();
+        assertTrue(set.trySet(5));
+        assertEquals(5, set.get().intValue());
+        assertFalse(set.trySet(7));
+        assertEquals(5, set.get().intValue());
+    }
+
+    public void testSetMultiThreaded() throws Exception {
+        final SetOnce<Integer> set = new SetOnce<>();
+        SetOnceThread[] threads = new SetOnceThread[10];
+        for (int i = 0; i < threads.length; i++) {
+            threads[i] = new SetOnceThread(random());
+            threads[i].setName("t-" + (i + 1));
+            threads[i].set = set;
+        }
+
+        for (Thread t : threads) {
+            t.start();
+        }
+
+        for (Thread t : threads) {
+            t.join();
+        }
+
+        for (SetOnceThread t : threads) {
+            if (t.success) {
+                int expectedVal = Integer.parseInt(t.getName().substring(2));
+                assertEquals("thread " + t.getName(), expectedVal, t.set.get().intValue());
+            }
+        }
+    }
+}
diff --git a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/CommonAnalysisModulePlugin.java b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/CommonAnalysisModulePlugin.java
index a26912733a9c6..67a0c3b13f8fb 100644
--- a/modules/analysis-common/src/main/java/org/opensearch/analysis/common/CommonAnalysisModulePlugin.java
+++ b/modules/analysis-common/src/main/java/org/opensearch/analysis/common/CommonAnalysisModulePlugin.java
@@ -123,11 +123,11 @@
 import org.apache.lucene.analysis.tr.ApostropheFilter;
 import org.apache.lucene.analysis.tr.TurkishAnalyzer;
 import org.apache.lucene.analysis.util.ElisionFilter;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.logging.DeprecationLogger;
 import org.opensearch.common.regex.Regex;
diff --git a/modules/ingest-geoip/src/main/java/org/opensearch/ingest/geoip/DatabaseReaderLazyLoader.java b/modules/ingest-geoip/src/main/java/org/opensearch/ingest/geoip/DatabaseReaderLazyLoader.java
index 70feb44f0f385..44b03744b6685 100644
--- a/modules/ingest-geoip/src/main/java/org/opensearch/ingest/geoip/DatabaseReaderLazyLoader.java
+++ b/modules/ingest-geoip/src/main/java/org/opensearch/ingest/geoip/DatabaseReaderLazyLoader.java
@@ -35,8 +35,8 @@
 import com.maxmind.geoip2.DatabaseReader;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.common.CheckedSupplier;
+import org.opensearch.common.SetOnce;
 import org.opensearch.core.internal.io.IOUtils;
 
 import java.io.Closeable;
diff --git a/modules/lang-painless/src/main/java/org/opensearch/painless/PainlessModulePlugin.java b/modules/lang-painless/src/main/java/org/opensearch/painless/PainlessModulePlugin.java
index 4a432b8f17b25..144f02ee7d74e 100644
--- a/modules/lang-painless/src/main/java/org/opensearch/painless/PainlessModulePlugin.java
+++ b/modules/lang-painless/src/main/java/org/opensearch/painless/PainlessModulePlugin.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.painless;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionResponse;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.IndexScopedSettings;
diff --git a/modules/percolator/src/main/java/org/opensearch/percolator/PercolateQueryBuilder.java b/modules/percolator/src/main/java/org/opensearch/percolator/PercolateQueryBuilder.java
index 4f4665c434c67..11d9d274e1e9b 100644
--- a/modules/percolator/src/main/java/org/opensearch/percolator/PercolateQueryBuilder.java
+++ b/modules/percolator/src/main/java/org/opensearch/percolator/PercolateQueryBuilder.java
@@ -54,13 +54,13 @@
 import org.apache.lucene.util.BitDocIdSet;
 import org.apache.lucene.util.BitSet;
 import org.apache.lucene.util.BytesRef;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.OpenSearchException;
 import org.opensearch.ResourceNotFoundException;
 import org.opensearch.Version;
 import org.opensearch.action.ActionListener;
 import org.opensearch.action.get.GetRequest;
 import org.opensearch.common.ParseField;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.InputStreamStreamInput;
 import org.opensearch.common.io.stream.NamedWriteableAwareStreamInput;
diff --git a/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexFromRemoteWithAuthTests.java b/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexFromRemoteWithAuthTests.java
index dd7eb977bbe48..a5de8e56c8d6f 100644
--- a/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexFromRemoteWithAuthTests.java
+++ b/modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexFromRemoteWithAuthTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.index.reindex;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.OpenSearchSecurityException;
 import org.opensearch.OpenSearchStatusException;
 import org.opensearch.action.ActionListener;
@@ -46,6 +45,7 @@
 import org.opensearch.client.Client;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.network.NetworkModule;
diff --git a/modules/systemd/src/main/java/org/opensearch/systemd/SystemdModulePlugin.java b/modules/systemd/src/main/java/org/opensearch/systemd/SystemdModulePlugin.java
index a22b3f862e017..a2966c059d4d2 100644
--- a/modules/systemd/src/main/java/org/opensearch/systemd/SystemdModulePlugin.java
+++ b/modules/systemd/src/main/java/org/opensearch/systemd/SystemdModulePlugin.java
@@ -34,10 +34,10 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.xcontent.NamedXContentRegistry;
diff --git a/modules/transport-netty4/src/main/java/org/opensearch/transport/Netty4ModulePlugin.java b/modules/transport-netty4/src/main/java/org/opensearch/transport/Netty4ModulePlugin.java
index 8a18210fd963e..5ad8b11f9fe6e 100644
--- a/modules/transport-netty4/src/main/java/org/opensearch/transport/Netty4ModulePlugin.java
+++ b/modules/transport-netty4/src/main/java/org/opensearch/transport/Netty4ModulePlugin.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.transport;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.network.NetworkService;
diff --git a/plugins/discovery-gce/src/main/java/org/opensearch/plugin/discovery/gce/GceDiscoveryPlugin.java b/plugins/discovery-gce/src/main/java/org/opensearch/plugin/discovery/gce/GceDiscoveryPlugin.java
index 6d015f54ffb29..282361c893689 100644
--- a/plugins/discovery-gce/src/main/java/org/opensearch/plugin/discovery/gce/GceDiscoveryPlugin.java
+++ b/plugins/discovery-gce/src/main/java/org/opensearch/plugin/discovery/gce/GceDiscoveryPlugin.java
@@ -36,13 +36,13 @@
 import com.google.api.client.util.ClassInfo;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.cloud.gce.GceInstancesService;
 import org.opensearch.cloud.gce.GceInstancesServiceImpl;
 import org.opensearch.cloud.gce.GceMetadataService;
 import org.opensearch.cloud.gce.network.GceNameResolver;
 import org.opensearch.cloud.gce.util.Access;
 import org.opensearch.common.Booleans;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
diff --git a/plugins/repository-hdfs/build.gradle b/plugins/repository-hdfs/build.gradle
index 0259be3428a82..481548e9a3252 100644
--- a/plugins/repository-hdfs/build.gradle
+++ b/plugins/repository-hdfs/build.gradle
@@ -66,7 +66,7 @@ dependencies {
   api 'org.apache.htrace:htrace-core4:4.2.0-incubating'
   api "org.apache.logging.log4j:log4j-core:${versions.log4j}"
   api 'org.apache.avro:avro:1.11.1'
-  api 'com.google.code.gson:gson:2.10'
+  api 'com.google.code.gson:gson:2.10.1'
   runtimeOnly 'com.google.guava:guava:31.1-jre'
   api 'com.google.protobuf:protobuf-java:3.21.12'
   api "commons-logging:commons-logging:${versions.commonslogging}"
diff --git a/plugins/repository-hdfs/licenses/gson-2.10.1.jar.sha1 b/plugins/repository-hdfs/licenses/gson-2.10.1.jar.sha1
new file mode 100644
index 0000000000000..9810309d1013a
--- /dev/null
+++ b/plugins/repository-hdfs/licenses/gson-2.10.1.jar.sha1
@@ -0,0 +1 @@
+b3add478d4382b78ea20b1671390a858002feb6c
\ No newline at end of file
diff --git a/plugins/repository-hdfs/licenses/gson-2.10.jar.sha1 b/plugins/repository-hdfs/licenses/gson-2.10.jar.sha1
deleted file mode 100644
index 64f28f71ab421..0000000000000
--- a/plugins/repository-hdfs/licenses/gson-2.10.jar.sha1
+++ /dev/null
@@ -1 +0,0 @@
-dd9b193aef96e973d5a11ab13cd17430c2e4306b
\ No newline at end of file
diff --git a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3BlobContainer.java b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3BlobContainer.java
index 678be7c6f13f2..c2c272b2527a2 100644
--- a/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3BlobContainer.java
+++ b/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3BlobContainer.java
@@ -48,9 +48,9 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.Strings;
 import org.opensearch.common.blobstore.BlobContainer;
 import org.opensearch.common.blobstore.BlobMetadata;
diff --git a/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/NioTransportPlugin.java b/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/NioTransportPlugin.java
index f8816e0686e9d..88e99b232d2da 100644
--- a/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/NioTransportPlugin.java
+++ b/plugins/transport-nio/src/main/java/org/opensearch/transport/nio/NioTransportPlugin.java
@@ -34,8 +34,8 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.network.NetworkService;
 import org.opensearch.common.settings.ClusterSettings;
diff --git a/qa/smoke-test-http/src/test/java/org/opensearch/http/SearchRestCancellationIT.java b/qa/smoke-test-http/src/test/java/org/opensearch/http/SearchRestCancellationIT.java
index 42c7357de3f07..c15678a3f2f38 100644
--- a/qa/smoke-test-http/src/test/java/org/opensearch/http/SearchRestCancellationIT.java
+++ b/qa/smoke-test-http/src/test/java/org/opensearch/http/SearchRestCancellationIT.java
@@ -34,7 +34,6 @@
 import org.apache.hc.core5.http.ContentType;
 import org.apache.hc.core5.http.io.entity.ByteArrayEntity;
 import org.apache.logging.log4j.LogManager;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.action.admin.cluster.node.info.NodeInfo;
 import org.opensearch.action.admin.cluster.node.info.NodesInfoResponse;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
@@ -48,6 +47,7 @@
 import org.opensearch.client.Request;
 import org.opensearch.client.Response;
 import org.opensearch.client.ResponseListener;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.Strings;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.plugins.Plugin;
diff --git a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/CancellableTasksIT.java b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/CancellableTasksIT.java
index 6c507171091e7..6743efda8e5e3 100644
--- a/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/CancellableTasksIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/node/tasks/CancellableTasksIT.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.action.admin.cluster.node.tasks;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.ResourceNotFoundException;
 import org.opensearch.action.ActionFuture;
@@ -50,6 +49,7 @@
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.inject.Inject;
 import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.io.stream.StreamOutput;
diff --git a/server/src/internalClusterTest/java/org/opensearch/cluster/routing/allocation/decider/DiskThresholdDeciderIT.java b/server/src/internalClusterTest/java/org/opensearch/cluster/routing/allocation/decider/DiskThresholdDeciderIT.java
index 4664648c03ccc..561e4349a4890 100644
--- a/server/src/internalClusterTest/java/org/opensearch/cluster/routing/allocation/decider/DiskThresholdDeciderIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/cluster/routing/allocation/decider/DiskThresholdDeciderIT.java
@@ -39,11 +39,14 @@
 
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
 import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotResponse;
+import org.opensearch.action.admin.indices.delete.DeleteIndexRequest;
 import org.opensearch.action.admin.indices.stats.ShardStats;
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.cluster.ClusterInfoService;
+import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.InternalClusterInfoService;
 import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
@@ -82,12 +85,15 @@
 import java.nio.file.NotDirectoryException;
 import java.nio.file.Path;
 import java.util.Arrays;
+import java.util.List;
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
@@ -126,7 +132,9 @@ public void removeFilesystemProvider() {
         defaultFileSystem = null;
     }
 
-    private static final long WATERMARK_BYTES = new ByteSizeValue(10, ByteSizeUnit.KB).getBytes();
+    // Increasing watermark limit to avoid flaky test case failures.
+    private static final long WATERMARK_BYTES = new ByteSizeValue(1, ByteSizeUnit.MB).getBytes();
+    private static final String INDEX_ROUTING_ALLOCATION_NODE_SETTING = "index.routing.allocation.include._name";
 
     @Override
     protected Settings nodeSettings(int nodeOrdinal) {
@@ -167,16 +175,7 @@ public void testHighWatermarkNotExceeded() throws Exception {
         final Path dataNode0Path = internalCluster().getInstance(Environment.class, dataNodeName).dataFiles()[0];
 
         final String indexName = randomAlphaOfLength(10).toLowerCase(Locale.ROOT);
-        createIndex(
-            indexName,
-            Settings.builder()
-                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
-                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 6)
-                .put(INDEX_STORE_STATS_REFRESH_INTERVAL_SETTING.getKey(), "0ms")
-                .put(IndexSettings.INDEX_MERGE_ON_FLUSH_ENABLED.getKey(), false)
-                .build()
-        );
-        final long minShardSize = createReasonableSizedShards(indexName);
+        final long minShardSize = createAndPopulateIndex(indexName, null);
 
         // reduce disk size of node 0 so that no shards fit below the high watermark, forcing all shards onto the other data node
         // (subtract the translog size since the disk threshold decider ignores this and may therefore move the shard back again)
@@ -188,6 +187,124 @@ public void testHighWatermarkNotExceeded() throws Exception {
         assertBusyWithDiskUsageRefresh(dataNode0Id, indexName, hasSize(1));
     }
 
+    public void testIndexCreateBlockWhenAllNodesExceededHighWatermark() throws Exception {
+        internalCluster().startClusterManagerOnlyNode();
+        final List<String> dataNodeNames = internalCluster().startDataOnlyNodes(2);
+        ensureStableCluster(3);
+
+        final InternalClusterInfoService clusterInfoService = (InternalClusterInfoService) internalCluster()
+            .getCurrentClusterManagerNodeInstance(ClusterInfoService.class);
+        internalCluster().getCurrentClusterManagerNodeInstance(ClusterService.class).addListener(event -> clusterInfoService.refresh());
+
+        // Reduce disk space of all node until all of them is breaching high disk watermark.
+        for (final String dataNodeName : dataNodeNames) {
+            populateNode(dataNodeName);
+        }
+
+        // Wait for all nodes to breach high disk watermark.
+        assertBusy(() -> {
+            refreshDiskUsage();
+            assertTrue(
+                StreamSupport.stream(clusterInfoService.getClusterInfo().getNodeLeastAvailableDiskUsages().values().spliterator(), false)
+                    .allMatch(cur -> cur.value.getFreeBytes() < WATERMARK_BYTES)
+            );
+        }, 30L, TimeUnit.SECONDS);
+
+        // Validate if cluster block is applied on the cluster
+        ClusterState state = client().admin().cluster().prepareState().setLocal(true).get().getState();
+        assertTrue(state.blocks().hasGlobalBlockWithId(Metadata.CLUSTER_CREATE_INDEX_BLOCK.id()));
+    }
+
+    public void testIndexCreateBlockNotAppliedWhenAnyNodesBelowHighWatermark() throws Exception {
+        internalCluster().startClusterManagerOnlyNode();
+        final List<String> dataNodeNames = internalCluster().startDataOnlyNodes(2);
+        ensureStableCluster(3);
+
+        final InternalClusterInfoService clusterInfoService = (InternalClusterInfoService) internalCluster()
+            .getCurrentClusterManagerNodeInstance(ClusterInfoService.class);
+        internalCluster().getCurrentClusterManagerNodeInstance(ClusterService.class).addListener(event -> clusterInfoService.refresh());
+
+        // Validate cluster block is not applied on the cluster
+        ClusterState state = client().admin().cluster().prepareState().setLocal(true).get().getState();
+        assertFalse(state.blocks().hasGlobalBlockWithId(Metadata.CLUSTER_CREATE_INDEX_BLOCK.id()));
+    }
+
+    public void testIndexCreateBlockIsRemovedWhenAnyNodesNotExceedHighWatermark() throws Exception {
+        internalCluster().startClusterManagerOnlyNode();
+        final List<String> dataNodeNames = internalCluster().startDataOnlyNodes(2);
+        final List<String> indexNames = new ArrayList<>();
+        ensureStableCluster(3);
+
+        final InternalClusterInfoService clusterInfoService = (InternalClusterInfoService) internalCluster()
+            .getCurrentClusterManagerNodeInstance(ClusterInfoService.class);
+        internalCluster().getCurrentClusterManagerNodeInstance(ClusterService.class).addListener(event -> clusterInfoService.refresh());
+
+        // Reduce disk space of all node until all of them is breaching high disk watermark.
+        for (final String dataNodeName : dataNodeNames) {
+            final String indexName = populateNode(dataNodeName);
+            indexNames.add(indexName);
+        }
+
+        // Wait for all the node to breach high disk watermark.
+        assertBusy(() -> {
+            refreshDiskUsage();
+            assertTrue(
+                StreamSupport.stream(clusterInfoService.getClusterInfo().getNodeLeastAvailableDiskUsages().values().spliterator(), false)
+                    .allMatch(cur -> cur.value.getFreeBytes() < WATERMARK_BYTES)
+            );
+        }, 30L, TimeUnit.SECONDS);
+
+        // Validate if index create block is applied on the cluster
+        ClusterState state = client().admin().cluster().prepareState().setLocal(true).get().getState();
+        assertTrue(state.blocks().hasGlobalBlockWithId(Metadata.CLUSTER_CREATE_INDEX_BLOCK.id()));
+
+        // Delete indices to free space
+        deleteIndices(indexNames);
+
+        // Validate if index create block is removed on the cluster
+        assertBusy(() -> {
+            refreshDiskUsage();
+            ClusterState state1 = client().admin().cluster().prepareState().setLocal(true).get().getState();
+            assertFalse(state1.blocks().hasGlobalBlockWithId(Metadata.CLUSTER_CREATE_INDEX_BLOCK.id()));
+        }, 30L, TimeUnit.SECONDS);
+    }
+
+    public void testIndexCreateBlockWithAReadOnlyBlock() throws Exception {
+        internalCluster().startClusterManagerOnlyNode();
+        final List<String> dataNodeNames = internalCluster().startDataOnlyNodes(2);
+        ensureStableCluster(3);
+        final InternalClusterInfoService clusterInfoService = (InternalClusterInfoService) internalCluster()
+            .getCurrentClusterManagerNodeInstance(ClusterInfoService.class);
+        internalCluster().getCurrentClusterManagerNodeInstance(ClusterService.class).addListener(event -> clusterInfoService.refresh());
+
+        // Create one of the index.
+        final String indexName = populateNode(dataNodeNames.get(0));
+
+        // Reduce disk space of all other node until all of them is breaching high disk watermark.
+        for (int i = 1; i < dataNodeNames.size(); i++) {
+            populateNode(dataNodeNames.get(i));
+        }
+
+        // Apply a read_only_allow_delete_block on one of the index
+        // (can happen if the corresponding node has breached flood stage watermark).
+        final Settings readOnlySettings = Settings.builder()
+            .put(IndexMetadata.SETTING_READ_ONLY_ALLOW_DELETE, Boolean.TRUE.toString())
+            .build();
+        client().admin().indices().prepareUpdateSettings(indexName).setSettings(readOnlySettings).get();
+
+        assertBusy(() -> {
+            refreshDiskUsage();
+            assertTrue(
+                StreamSupport.stream(clusterInfoService.getClusterInfo().getNodeLeastAvailableDiskUsages().values().spliterator(), false)
+                    .allMatch(cur -> cur.value.getFreeBytes() < WATERMARK_BYTES)
+            );
+        }, 30L, TimeUnit.SECONDS);
+
+        // Validate index create block is applied on the cluster.
+        ClusterState state = client().admin().cluster().prepareState().setLocal(true).get().getState();
+        assertTrue(state.blocks().hasGlobalBlockWithId(Metadata.CLUSTER_CREATE_INDEX_BLOCK.id()));
+    }
+
     public void testRestoreSnapshotAllocationDoesNotExceedWatermark() throws Exception {
         internalCluster().startClusterManagerOnlyNode();
         internalCluster().startDataOnlyNode();
@@ -210,16 +327,7 @@ public void testRestoreSnapshotAllocationDoesNotExceedWatermark() throws Excepti
         final Path dataNode0Path = internalCluster().getInstance(Environment.class, dataNodeName).dataFiles()[0];
 
         final String indexName = randomAlphaOfLength(10).toLowerCase(Locale.ROOT);
-        createIndex(
-            indexName,
-            Settings.builder()
-                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
-                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 6)
-                .put(INDEX_STORE_STATS_REFRESH_INTERVAL_SETTING.getKey(), "0ms")
-                .put(IndexSettings.INDEX_MERGE_ON_FLUSH_ENABLED.getKey(), false)
-                .build()
-        );
-        final long minShardSize = createReasonableSizedShards(indexName);
+        final long minShardSize = createAndPopulateIndex(indexName, null);
 
         final CreateSnapshotResponse createSnapshotResponse = client().admin()
             .cluster()
@@ -274,6 +382,40 @@ public void testRestoreSnapshotAllocationDoesNotExceedWatermark() throws Excepti
         assertBusyWithDiskUsageRefresh(dataNode0Id, indexName, hasSize(1));
     }
 
+    private void deleteIndices(final List<String> indexNames) throws ExecutionException, InterruptedException {
+        for (String indexName : indexNames) {
+            assertAcked(client().admin().indices().delete(new DeleteIndexRequest(indexName)).get());
+            assertFalse("index [" + indexName + "] should have been deleted", indexExists(indexName));
+        }
+    }
+
+    private String populateNode(final String dataNodeName) throws Exception {
+        final Path dataNodePath = internalCluster().getInstance(Environment.class, dataNodeName).dataFiles()[0];
+        final String indexName = randomAlphaOfLength(10).toLowerCase(Locale.ROOT);
+        long minShardSize = createAndPopulateIndex(indexName, dataNodeName);
+        fileSystemProvider.getTestFileStore(dataNodePath).setTotalSpace(minShardSize + WATERMARK_BYTES - 1L);
+        refreshDiskUsage();
+        return indexName;
+    }
+
+    private long createAndPopulateIndex(final String indexName, final String nodeName) throws Exception {
+
+        final Settings.Builder indexSettingBuilder = Settings.builder()
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
+            .put(INDEX_STORE_STATS_REFRESH_INTERVAL_SETTING.getKey(), "0ms")
+            .put(IndexSettings.INDEX_MERGE_ON_FLUSH_ENABLED.getKey(), false);
+
+        // Depending on node name specified or not, we determine whether to enable node name based shard routing for index.
+        if (nodeName != null) {
+            indexSettingBuilder.put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1).put(INDEX_ROUTING_ALLOCATION_NODE_SETTING, nodeName);
+        } else {
+            indexSettingBuilder.put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 6);
+        }
+
+        createIndex(indexName, indexSettingBuilder.build());
+        return createReasonableSizedShards(indexName);
+    }
+
     private Set<ShardRouting> getShardRoutings(final String nodeId, final String indexName) {
         final Set<ShardRouting> shardRoutings = new HashSet<>();
         for (IndexShardRoutingTable indexShardRoutingTable : client().admin()
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/recovery/IndexRecoveryIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/recovery/IndexRecoveryIT.java
index bb1456c8b5d4f..a7ab1dc7c7d39 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/recovery/IndexRecoveryIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/recovery/IndexRecoveryIT.java
@@ -34,7 +34,6 @@
 
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.index.IndexCommit;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
 import org.opensearch.action.admin.cluster.health.ClusterHealthResponse;
@@ -72,6 +71,7 @@
 import org.opensearch.cluster.routing.allocation.command.MoveAllocationCommand;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Priority;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.Strings;
 import org.opensearch.common.breaker.CircuitBreaker;
 import org.opensearch.common.breaker.CircuitBreakingException;
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationIT.java
index 93cb721226673..bc5c5abb5386d 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationIT.java
@@ -116,10 +116,10 @@ public void ingestDocs(int docCount) throws Exception {
 
     @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/5669")
     public void testPrimaryStopped_ReplicaPromoted() throws Exception {
-        final String primary = internalCluster().startNode(featureFlagSettings());
+        final String primary = internalCluster().startNode();
         createIndex(INDEX_NAME);
         ensureYellowAndNoInitializingShards(INDEX_NAME);
-        final String replica = internalCluster().startNode(featureFlagSettings());
+        final String replica = internalCluster().startNode();
         ensureGreen(INDEX_NAME);
 
         client().prepareIndex(INDEX_NAME).setId("1").setSource("foo", "bar").setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE).get();
@@ -146,7 +146,7 @@ public void testPrimaryStopped_ReplicaPromoted() throws Exception {
         assertHitCount(client(replica).prepareSearch(INDEX_NAME).setSize(0).setPreference("_only_local").get(), 3);
 
         // start another node, index another doc and replicate.
-        String nodeC = internalCluster().startNode(featureFlagSettings());
+        String nodeC = internalCluster().startNode();
         ensureGreen(INDEX_NAME);
         client().prepareIndex(INDEX_NAME).setId("4").setSource("baz", "baz").get();
         refresh(INDEX_NAME);
@@ -158,10 +158,10 @@ public void testPrimaryStopped_ReplicaPromoted() throws Exception {
 
     @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/5669")
     public void testRestartPrimary() throws Exception {
-        final String primary = internalCluster().startNode(featureFlagSettings());
+        final String primary = internalCluster().startNode();
         createIndex(INDEX_NAME);
         ensureYellowAndNoInitializingShards(INDEX_NAME);
-        final String replica = internalCluster().startNode(featureFlagSettings());
+        final String replica = internalCluster().startNode();
         ensureGreen(INDEX_NAME);
 
         assertEquals(getNodeContainingPrimaryShard().getName(), primary);
@@ -188,10 +188,10 @@ public void testRestartPrimary() throws Exception {
     @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/5669")
     public void testCancelPrimaryAllocation() throws Exception {
         // this test cancels allocation on the primary - promoting the new replica and recreating the former primary as a replica.
-        final String primary = internalCluster().startNode(featureFlagSettings());
+        final String primary = internalCluster().startNode();
         createIndex(INDEX_NAME);
         ensureYellowAndNoInitializingShards(INDEX_NAME);
-        final String replica = internalCluster().startNode(featureFlagSettings());
+        final String replica = internalCluster().startNode();
         ensureGreen(INDEX_NAME);
 
         final int initialDocCount = 1;
@@ -228,7 +228,7 @@ public void testCancelPrimaryAllocation() throws Exception {
     @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/5669")
     public void testAddNewReplicaFailure() throws Exception {
         logger.info("--> starting [Primary Node] ...");
-        final String primaryNode = internalCluster().startNode(featureFlagSettings());
+        final String primaryNode = internalCluster().startNode();
 
         logger.info("--> creating test index ...");
         prepareCreate(
@@ -251,7 +251,7 @@ public void testAddNewReplicaFailure() throws Exception {
         assertThat(client().prepareSearch(INDEX_NAME).setSize(0).execute().actionGet().getHits().getTotalHits().value, equalTo(20L));
 
         logger.info("--> start empty node to add replica shard");
-        final String replicaNode = internalCluster().startNode(featureFlagSettings());
+        final String replicaNode = internalCluster().startNode();
 
         // Mock transport service to add behaviour of throwing corruption exception during segment replication process.
         MockTransportService mockTransportService = ((MockTransportService) internalCluster().getInstance(
@@ -294,8 +294,8 @@ public void testAddNewReplicaFailure() throws Exception {
 
     @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/5669")
     public void testReplicationAfterPrimaryRefreshAndFlush() throws Exception {
-        final String nodeA = internalCluster().startNode(featureFlagSettings());
-        final String nodeB = internalCluster().startNode(featureFlagSettings());
+        final String nodeA = internalCluster().startNode();
+        final String nodeB = internalCluster().startNode();
         createIndex(INDEX_NAME);
         ensureGreen(INDEX_NAME);
 
@@ -335,8 +335,8 @@ public void testReplicationAfterPrimaryRefreshAndFlush() throws Exception {
     }
 
     public void testIndexReopenClose() throws Exception {
-        final String primary = internalCluster().startNode(featureFlagSettings());
-        final String replica = internalCluster().startNode(featureFlagSettings());
+        final String primary = internalCluster().startNode();
+        final String replica = internalCluster().startNode();
         createIndex(INDEX_NAME);
         ensureGreen(INDEX_NAME);
 
@@ -380,8 +380,8 @@ public void testMultipleShards() throws Exception {
             .put(IndexModule.INDEX_QUERY_CACHE_ENABLED_SETTING.getKey(), false)
             .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
             .build();
-        final String nodeA = internalCluster().startNode(featureFlagSettings());
-        final String nodeB = internalCluster().startNode(featureFlagSettings());
+        final String nodeA = internalCluster().startNode();
+        final String nodeB = internalCluster().startNode();
         createIndex(INDEX_NAME, indexSettings);
         ensureGreen(INDEX_NAME);
 
@@ -421,8 +421,8 @@ public void testMultipleShards() throws Exception {
     }
 
     public void testReplicationAfterForceMerge() throws Exception {
-        final String nodeA = internalCluster().startNode(featureFlagSettings());
-        final String nodeB = internalCluster().startNode(featureFlagSettings());
+        final String nodeA = internalCluster().startNode();
+        final String nodeB = internalCluster().startNode();
         createIndex(INDEX_NAME);
         ensureGreen(INDEX_NAME);
 
@@ -466,11 +466,11 @@ public void testReplicationAfterForceMerge() throws Exception {
     }
 
     public void testCancellation() throws Exception {
-        final String primaryNode = internalCluster().startNode(featureFlagSettings());
+        final String primaryNode = internalCluster().startNode();
         createIndex(INDEX_NAME, Settings.builder().put(indexSettings()).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1).build());
         ensureYellow(INDEX_NAME);
 
-        final String replicaNode = internalCluster().startNode(featureFlagSettings());
+        final String replicaNode = internalCluster().startNode();
 
         final SegmentReplicationSourceService segmentReplicationSourceService = internalCluster().getInstance(
             SegmentReplicationSourceService.class,
@@ -525,7 +525,7 @@ public void testCancellation() throws Exception {
     }
 
     public void testStartReplicaAfterPrimaryIndexesDocs() throws Exception {
-        final String primaryNode = internalCluster().startNode(featureFlagSettings());
+        final String primaryNode = internalCluster().startNode();
         createIndex(INDEX_NAME, Settings.builder().put(indexSettings()).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0).build());
         ensureGreen(INDEX_NAME);
 
@@ -548,7 +548,7 @@ public void testStartReplicaAfterPrimaryIndexesDocs() throws Exception {
                 .prepareUpdateSettings(INDEX_NAME)
                 .setSettings(Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1))
         );
-        final String replicaNode = internalCluster().startNode(featureFlagSettings());
+        final String replicaNode = internalCluster().startNode();
         ensureGreen(INDEX_NAME);
 
         assertHitCount(client(primaryNode).prepareSearch(INDEX_NAME).setSize(0).setPreference("_only_local").get(), 2);
@@ -563,8 +563,8 @@ public void testStartReplicaAfterPrimaryIndexesDocs() throws Exception {
     }
 
     public void testDeleteOperations() throws Exception {
-        final String nodeA = internalCluster().startNode(featureFlagSettings());
-        final String nodeB = internalCluster().startNode(featureFlagSettings());
+        final String nodeA = internalCluster().startNode();
+        final String nodeB = internalCluster().startNode();
 
         createIndex(INDEX_NAME);
         ensureGreen(INDEX_NAME);
@@ -627,10 +627,10 @@ public void testDeleteOperations() throws Exception {
 
     @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/5669")
     public void testUpdateOperations() throws Exception {
-        final String primary = internalCluster().startNode(featureFlagSettings());
+        final String primary = internalCluster().startNode();
         createIndex(INDEX_NAME);
         ensureYellow(INDEX_NAME);
-        final String replica = internalCluster().startNode(featureFlagSettings());
+        final String replica = internalCluster().startNode();
 
         final int initialDocCount = scaledRandomIntBetween(0, 200);
         try (
@@ -731,10 +731,10 @@ public void testDropPrimaryDuringReplication() throws Exception {
             .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 6)
             .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
             .build();
-        final String clusterManagerNode = internalCluster().startClusterManagerOnlyNode(featureFlagSettings());
-        final String primaryNode = internalCluster().startDataOnlyNode(featureFlagSettings());
+        final String clusterManagerNode = internalCluster().startClusterManagerOnlyNode();
+        final String primaryNode = internalCluster().startDataOnlyNode();
         createIndex(INDEX_NAME, settings);
-        internalCluster().startDataOnlyNodes(6, featureFlagSettings());
+        internalCluster().startDataOnlyNodes(6);
         ensureGreen(INDEX_NAME);
 
         int initialDocCount = scaledRandomIntBetween(100, 200);
@@ -757,7 +757,7 @@ public void testDropPrimaryDuringReplication() throws Exception {
             ensureYellow(INDEX_NAME);
 
             // start another replica.
-            internalCluster().startDataOnlyNode(featureFlagSettings());
+            internalCluster().startDataOnlyNode();
             ensureGreen(INDEX_NAME);
 
             // index another doc and refresh - without this the new replica won't catch up.
diff --git a/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationRelocationIT.java b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationRelocationIT.java
index 19cd296e30eac..fb8b6a7150b9a 100644
--- a/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationRelocationIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationRelocationIT.java
@@ -57,9 +57,9 @@ private void createIndex() {
      */
     @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/5669")
     public void testPrimaryRelocation() throws Exception {
-        final String oldPrimary = internalCluster().startNode(featureFlagSettings());
+        final String oldPrimary = internalCluster().startNode();
         createIndex();
-        final String replica = internalCluster().startNode(featureFlagSettings());
+        final String replica = internalCluster().startNode();
         ensureGreen(INDEX_NAME);
         final int initialDocCount = scaledRandomIntBetween(0, 200);
         ingestDocs(initialDocCount);
@@ -69,7 +69,7 @@ public void testPrimaryRelocation() throws Exception {
         assertHitCount(client(replica).prepareSearch(INDEX_NAME).setSize(0).setPreference("_only_local").get(), initialDocCount);
 
         logger.info("--> start another node");
-        final String newPrimary = internalCluster().startNode(featureFlagSettings());
+        final String newPrimary = internalCluster().startNode();
         ClusterHealthResponse clusterHealthResponse = client().admin()
             .cluster()
             .prepareHealth()
@@ -129,9 +129,9 @@ public void testPrimaryRelocation() throws Exception {
      */
     @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/5669")
     public void testPrimaryRelocationWithSegRepFailure() throws Exception {
-        final String oldPrimary = internalCluster().startNode(featureFlagSettings());
+        final String oldPrimary = internalCluster().startNode();
         createIndex();
-        final String replica = internalCluster().startNode(featureFlagSettings());
+        final String replica = internalCluster().startNode();
         ensureGreen(INDEX_NAME);
         final int initialDocCount = scaledRandomIntBetween(1, 100);
         ingestDocs(initialDocCount);
@@ -141,7 +141,7 @@ public void testPrimaryRelocationWithSegRepFailure() throws Exception {
         assertHitCount(client(replica).prepareSearch(INDEX_NAME).setSize(0).setPreference("_only_local").get(), initialDocCount);
 
         logger.info("--> start another node");
-        final String newPrimary = internalCluster().startNode(featureFlagSettings());
+        final String newPrimary = internalCluster().startNode();
         ClusterHealthResponse clusterHealthResponse = client().admin()
             .cluster()
             .prepareHealth()
@@ -204,7 +204,7 @@ public void testPrimaryRelocationWithSegRepFailure() throws Exception {
      *
      */
     public void testRelocateWhileContinuouslyIndexingAndWaitingForRefresh() throws Exception {
-        final String primary = internalCluster().startNode(featureFlagSettings());
+        final String primary = internalCluster().startNode();
         prepareCreate(
             INDEX_NAME,
             Settings.builder()
@@ -233,7 +233,7 @@ public void testRelocateWhileContinuouslyIndexingAndWaitingForRefresh() throws E
             );
         }
 
-        final String replica = internalCluster().startNode(featureFlagSettings());
+        final String replica = internalCluster().startNode();
         ClusterHealthResponse clusterHealthResponse = client().admin()
             .cluster()
             .prepareHealth()
diff --git a/server/src/internalClusterTest/java/org/opensearch/search/SearchWeightedRoutingIT.java b/server/src/internalClusterTest/java/org/opensearch/search/SearchWeightedRoutingIT.java
index 4c32929a85373..279b07344b3f9 100644
--- a/server/src/internalClusterTest/java/org/opensearch/search/SearchWeightedRoutingIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/search/SearchWeightedRoutingIT.java
@@ -851,7 +851,7 @@ public void testPreferenceSearchWithWeightedRouting() throws Exception {
         Map<String, List<String>> nodeMap = setupCluster(nodeCountPerAZ, commonSettings);
 
         int numShards = 10;
-        int numReplicas = 1;
+        int numReplicas = 2;
         setUpIndexing(numShards, numReplicas);
 
         logger.info("--> setting shard routing weights for weighted round robin");
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/SearchableSnapshotIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/SearchableSnapshotIT.java
index 53b70aa915a37..e06c220e2caf9 100644
--- a/server/src/internalClusterTest/java/org/opensearch/snapshots/SearchableSnapshotIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/SearchableSnapshotIT.java
@@ -6,13 +6,13 @@
 
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
 import org.hamcrest.MatcherAssert;
-import org.junit.BeforeClass;
 import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
 import org.opensearch.action.admin.cluster.snapshots.delete.DeleteSnapshotRequest;
 import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotRequest;
 import org.opensearch.action.admin.indices.settings.put.UpdateSettingsRequestBuilder;
 import org.opensearch.action.index.IndexRequestBuilder;
+import org.opensearch.action.support.master.AcknowledgedResponse;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
@@ -38,24 +38,22 @@
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.contains;
+import static org.hamcrest.Matchers.notNullValue;
 import static org.opensearch.action.admin.cluster.node.stats.NodesStatsRequest.Metric.FS;
 import static org.opensearch.common.util.CollectionUtils.iterableAsArrayList;
 
 public final class SearchableSnapshotIT extends AbstractSnapshotIntegTestCase {
 
-    @BeforeClass
-    public static void assumeFeatureFlag() {
-        assumeTrue(
-            "Searchable snapshot feature flag is enabled",
-            Boolean.parseBoolean(System.getProperty(FeatureFlags.SEARCHABLE_SNAPSHOT))
-        );
-    }
-
     @Override
     protected boolean addMockInternalEngine() {
         return false;
     }
 
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(FeatureFlags.SEARCHABLE_SNAPSHOT, "true").build();
+    }
+
     @Override
     protected Settings.Builder randomRepositorySettings() {
         final Settings.Builder settings = Settings.builder();
@@ -214,7 +212,6 @@ public void testSearchableSnapshotIndexIsReadOnly() throws Exception {
         restoreSnapshotAndEnsureGreen(client, snapshotName, repoName);
 
         assertIndexingBlocked(restoredIndexName);
-        assertIndexSettingChangeBlocked(restoredIndexName);
         assertTrue(client.admin().indices().prepareDelete(restoredIndexName).get().isAcknowledged());
         assertThrows(
             "Expect index to not exist",
@@ -325,7 +322,27 @@ private void assertIndexingBlocked(String index) {
         }
     }
 
-    private void assertIndexSettingChangeBlocked(String index) {
+    public void testUpdateIndexSettings() throws InterruptedException {
+        final String indexName = "test-index";
+        final String restoredIndexName = indexName + "-copy";
+        final String repoName = "test-repo";
+        final String snapshotName = "test-snap";
+        final Client client = client();
+
+        createIndexWithDocsAndEnsureGreen(0, 100, indexName);
+        createRepositoryWithSettings(null, repoName);
+        takeSnapshot(client, snapshotName, repoName, indexName);
+        deleteIndicesAndEnsureGreen(client, indexName);
+
+        internalCluster().ensureAtLeastNumSearchNodes(1);
+        restoreSnapshotAndEnsureGreen(client, snapshotName, repoName);
+
+        testUpdateIndexSettingsOnlyNotAllowedSettings(restoredIndexName);
+        testUpdateIndexSettingsOnlyAllowedSettings(restoredIndexName);
+        testUpdateIndexSettingsAtLeastOneNotAllowedSettings(restoredIndexName);
+    }
+
+    private void testUpdateIndexSettingsOnlyNotAllowedSettings(String index) {
         try {
             final UpdateSettingsRequestBuilder builder = client().admin().indices().prepareUpdateSettings(index);
             builder.setSettings(Map.of("index.refresh_interval", 10));
@@ -336,6 +353,26 @@ private void assertIndexSettingChangeBlocked(String index) {
         }
     }
 
+    private void testUpdateIndexSettingsOnlyAllowedSettings(String index) {
+        final UpdateSettingsRequestBuilder builder = client().admin().indices().prepareUpdateSettings(index);
+        builder.setSettings(Map.of("index.max_result_window", 1000, "index.search.slowlog.threshold.query.warn", "10s"));
+        AcknowledgedResponse settingsResponse = builder.execute().actionGet();
+        assertThat(settingsResponse, notNullValue());
+    }
+
+    private void testUpdateIndexSettingsAtLeastOneNotAllowedSettings(String index) {
+        try {
+            final UpdateSettingsRequestBuilder builder = client().admin().indices().prepareUpdateSettings(index);
+            builder.setSettings(
+                Map.of("index.max_result_window", 5000, "index.search.slowlog.threshold.query.warn", "15s", "index.refresh_interval", 10)
+            );
+            builder.execute().actionGet();
+            fail("Expected operation to throw an exception");
+        } catch (ClusterBlockException e) {
+            MatcherAssert.assertThat(e.blocks(), contains(IndexMetadata.REMOTE_READ_ONLY_ALLOW_DELETE));
+        }
+    }
+
     /**
      * Picks a shard out of the cluster state for each given index and asserts
      * that the 'index' directory does not exist in the node's file system.
diff --git a/server/src/internalClusterTest/java/org/opensearch/snapshots/SegmentReplicationSnapshotIT.java b/server/src/internalClusterTest/java/org/opensearch/snapshots/SegmentReplicationSnapshotIT.java
index a741797012602..2b44a20406b05 100644
--- a/server/src/internalClusterTest/java/org/opensearch/snapshots/SegmentReplicationSnapshotIT.java
+++ b/server/src/internalClusterTest/java/org/opensearch/snapshots/SegmentReplicationSnapshotIT.java
@@ -99,11 +99,11 @@ public void ingestData(int docCount, String indexName) throws Exception {
     // Start cluster with provided settings and return the node names as list
     public List<String> startClusterWithSettings(Settings indexSettings, int replicaCount) throws Exception {
         // Start primary
-        final String primaryNode = internalCluster().startNode(featureFlagSettings());
+        final String primaryNode = internalCluster().startNode();
         List<String> nodeNames = new ArrayList<>();
         nodeNames.add(primaryNode);
         for (int i = 0; i < replicaCount; i++) {
-            nodeNames.add(internalCluster().startNode(featureFlagSettings()));
+            nodeNames.add(internalCluster().startNode());
         }
         createIndex(INDEX_NAME, indexSettings);
         ensureGreen(INDEX_NAME);
@@ -266,7 +266,7 @@ public void testRestoreOnReplicaNode() throws Exception {
 
         // Assertions
         assertThat(restoreSnapshotResponse.status(), equalTo(RestStatus.ACCEPTED));
-        internalCluster().startNode(featureFlagSettings());
+        internalCluster().startNode();
         ensureGreen(RESTORED_INDEX_NAME);
         GetSettingsResponse settingsResponse = client().admin()
             .indices()
diff --git a/server/src/main/java/org/opensearch/Version.java b/server/src/main/java/org/opensearch/Version.java
index 77286c42dc4c2..0ddfd8c21b085 100644
--- a/server/src/main/java/org/opensearch/Version.java
+++ b/server/src/main/java/org/opensearch/Version.java
@@ -85,6 +85,7 @@ public class Version implements Comparable<Version>, ToXContentFragment {
     public static final Version V_2_4_0 = new Version(2040099, org.apache.lucene.util.Version.LUCENE_9_4_1);
     public static final Version V_2_4_1 = new Version(2040199, org.apache.lucene.util.Version.LUCENE_9_4_2);
     public static final Version V_2_5_0 = new Version(2050099, org.apache.lucene.util.Version.LUCENE_9_4_2);
+    public static final Version V_2_5_1 = new Version(2050199, org.apache.lucene.util.Version.LUCENE_9_4_2);
 
     // UNRELEASED
     public static final Version V_2_4_2 = new Version(2040299, org.apache.lucene.util.Version.LUCENE_9_4_2);
diff --git a/server/src/main/java/org/opensearch/action/admin/indices/settings/put/TransportUpdateSettingsAction.java b/server/src/main/java/org/opensearch/action/admin/indices/settings/put/TransportUpdateSettingsAction.java
index a959fb043e4c6..a1c3b9341fd40 100644
--- a/server/src/main/java/org/opensearch/action/admin/indices/settings/put/TransportUpdateSettingsAction.java
+++ b/server/src/main/java/org/opensearch/action/admin/indices/settings/put/TransportUpdateSettingsAction.java
@@ -49,11 +49,17 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.inject.Inject;
 import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.Index;
+import org.opensearch.index.IndexModule;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
+import java.util.stream.Stream;
+import java.util.Set;
+
+import static org.opensearch.index.IndexModule.INDEX_STORE_TYPE_SETTING;
 
 /**
  * Transport action for updating index settings
@@ -64,6 +70,19 @@ public class TransportUpdateSettingsAction extends TransportClusterManagerNodeAc
 
     private static final Logger logger = LogManager.getLogger(TransportUpdateSettingsAction.class);
 
+    private final static Set<String> ALLOWLIST_REMOTE_SNAPSHOT_SETTINGS = Set.of(
+        "index.max_result_window",
+        "index.max_inner_result_window",
+        "index.max_rescore_window",
+        "index.max_docvalue_fields_search",
+        "index.max_script_fields",
+        "index.max_terms_count",
+        "index.max_regex_length",
+        "index.highlight.max_analyzed_offset"
+    );
+
+    private final static String[] ALLOWLIST_REMOTE_SNAPSHOT_SETTINGS_PREFIXES = { "index.search.slowlog" };
+
     private final MetadataUpdateSettingsService updateSettingsService;
 
     @Inject
@@ -106,6 +125,37 @@ protected ClusterBlockException checkBlock(UpdateSettingsRequest request, Cluste
             || IndexMetadata.INDEX_BLOCKS_READ_ONLY_ALLOW_DELETE_SETTING.exists(request.settings())) {
             return null;
         }
+
+        if (FeatureFlags.isEnabled(FeatureFlags.SEARCHABLE_SNAPSHOT)) {
+            final Index[] requestIndices = indexNameExpressionResolver.concreteIndices(state, request);
+            boolean allowSearchableSnapshotSettingsUpdate = true;
+            // check if all indices in the request are remote snapshot
+            for (Index index : requestIndices) {
+                if (state.blocks().indexBlocked(ClusterBlockLevel.METADATA_WRITE, index.getName())) {
+                    allowSearchableSnapshotSettingsUpdate = allowSearchableSnapshotSettingsUpdate
+                        && IndexModule.Type.REMOTE_SNAPSHOT.match(
+                            state.getMetadata().getIndexSafe(index).getSettings().get(INDEX_STORE_TYPE_SETTING.getKey())
+                        );
+                }
+            }
+            // check if all settings in the request are in the allow list
+            if (allowSearchableSnapshotSettingsUpdate) {
+                for (String setting : request.settings().keySet()) {
+                    allowSearchableSnapshotSettingsUpdate = allowSearchableSnapshotSettingsUpdate
+                        && (ALLOWLIST_REMOTE_SNAPSHOT_SETTINGS.contains(setting)
+                            || Stream.of(ALLOWLIST_REMOTE_SNAPSHOT_SETTINGS_PREFIXES).anyMatch(setting::startsWith));
+                }
+            }
+
+            return allowSearchableSnapshotSettingsUpdate
+                ? null
+                : state.blocks()
+                    .indicesBlockedException(
+                        ClusterBlockLevel.METADATA_WRITE,
+                        indexNameExpressionResolver.concreteIndexNames(state, request)
+                    );
+        }
+
         return state.blocks()
             .indicesBlockedException(ClusterBlockLevel.METADATA_WRITE, indexNameExpressionResolver.concreteIndexNames(state, request));
     }
diff --git a/server/src/main/java/org/opensearch/action/search/AbstractSearchAsyncAction.java b/server/src/main/java/org/opensearch/action/search/AbstractSearchAsyncAction.java
index 1a37406e19f14..6b6678361b2b5 100644
--- a/server/src/main/java/org/opensearch/action/search/AbstractSearchAsyncAction.java
+++ b/server/src/main/java/org/opensearch/action/search/AbstractSearchAsyncAction.java
@@ -34,7 +34,6 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
@@ -46,6 +45,7 @@
 import org.opensearch.cluster.routing.FailAwareWeightedRouting;
 import org.opensearch.cluster.routing.GroupShardsIterator;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.util.concurrent.AbstractRunnable;
diff --git a/server/src/main/java/org/opensearch/cluster/coordination/Coordinator.java b/server/src/main/java/org/opensearch/cluster/coordination/Coordinator.java
index fd52f48c7b5f8..eb069dc1f7698 100644
--- a/server/src/main/java/org/opensearch/cluster/coordination/Coordinator.java
+++ b/server/src/main/java/org/opensearch/cluster/coordination/Coordinator.java
@@ -35,7 +35,6 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterChangedEvent;
 import org.opensearch.cluster.ClusterName;
@@ -61,6 +60,7 @@
 import org.opensearch.common.Booleans;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Priority;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.Strings;
 import org.opensearch.common.component.AbstractLifecycleComponent;
 import org.opensearch.common.io.stream.NamedWriteableRegistry;
diff --git a/server/src/main/java/org/opensearch/cluster/metadata/IndexAbstraction.java b/server/src/main/java/org/opensearch/cluster/metadata/IndexAbstraction.java
index 975c71ab75110..f9328d5b61183 100644
--- a/server/src/main/java/org/opensearch/cluster/metadata/IndexAbstraction.java
+++ b/server/src/main/java/org/opensearch/cluster/metadata/IndexAbstraction.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.cluster.metadata;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.Strings;
 import org.opensearch.common.collect.Tuple;
 
diff --git a/server/src/main/java/org/opensearch/cluster/routing/allocation/DiskThresholdMonitor.java b/server/src/main/java/org/opensearch/cluster/routing/allocation/DiskThresholdMonitor.java
index 0a6cfd8c04977..4eb39caa2fdcf 100644
--- a/server/src/main/java/org/opensearch/cluster/routing/allocation/DiskThresholdMonitor.java
+++ b/server/src/main/java/org/opensearch/cluster/routing/allocation/DiskThresholdMonitor.java
@@ -45,6 +45,7 @@
 import org.opensearch.cluster.DiskUsage;
 import org.opensearch.cluster.block.ClusterBlockLevel;
 import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.routing.RerouteService;
 import org.opensearch.cluster.routing.RoutingNode;
 import org.opensearch.cluster.routing.RoutingNodes;
@@ -78,7 +79,6 @@
 public class DiskThresholdMonitor {
 
     private static final Logger logger = LogManager.getLogger(DiskThresholdMonitor.class);
-
     private final DiskThresholdSettings diskThresholdSettings;
     private final Client client;
     private final Supplier<ClusterState> clusterStateSupplier;
@@ -286,7 +286,7 @@ public void onNewInfo(ClusterInfo info) {
                 }
         }
 
-        final ActionListener<Void> listener = new GroupedActionListener<>(ActionListener.wrap(this::checkFinished), 3);
+        final ActionListener<Void> listener = new GroupedActionListener<>(ActionListener.wrap(this::checkFinished), 4);
 
         if (reroute) {
             logger.debug("rerouting shards: [{}]", explanation);
@@ -373,6 +373,15 @@ public void onNewInfo(ClusterInfo info) {
         } else {
             listener.onResponse(null);
         }
+
+        // If all the nodes are breaching high disk watermark, we apply index create block to avoid red clusters.
+        if (nodesOverHighThreshold.size() == nodes.size()) {
+            setIndexCreateBlock(listener, true);
+        } else if (state.getBlocks().hasGlobalBlockWithId(Metadata.CLUSTER_CREATE_INDEX_BLOCK.id())) {
+            setIndexCreateBlock(listener, false);
+        } else {
+            listener.onResponse(null);
+        }
     }
 
     // exposed for tests to override
@@ -406,6 +415,27 @@ private void setLastRunTimeMillis() {
         lastRunTimeMillis.getAndUpdate(l -> Math.max(l, currentTimeMillisSupplier.getAsLong()));
     }
 
+    protected void setIndexCreateBlock(final ActionListener<Void> listener, boolean indexCreateBlock) {
+        final ActionListener<Void> wrappedListener = ActionListener.wrap(r -> {
+            setLastRunTimeMillis();
+            listener.onResponse(r);
+        }, e -> {
+            logger.debug("setting index create block failed", e);
+            setLastRunTimeMillis();
+            listener.onFailure(e);
+        });
+
+        final Settings indexCreateBlockSetting = indexCreateBlock
+            ? Settings.builder().put(Metadata.SETTING_CREATE_INDEX_BLOCK_SETTING.getKey(), Boolean.TRUE.toString()).build()
+            : Settings.builder().putNull(Metadata.SETTING_CREATE_INDEX_BLOCK_SETTING.getKey()).build();
+
+        client.admin()
+            .cluster()
+            .prepareUpdateSettings()
+            .setPersistentSettings(indexCreateBlockSetting)
+            .execute(ActionListener.map(wrappedListener, r -> null));
+    }
+
     protected void updateIndicesReadOnly(Set<String> indicesToUpdate, ActionListener<Void> listener, boolean readOnly) {
         // set read-only block but don't block on the response
         ActionListener<Void> wrappedListener = ActionListener.wrap(r -> {
diff --git a/server/src/main/java/org/opensearch/common/logging/NodeAndClusterIdConverter.java b/server/src/main/java/org/opensearch/common/logging/NodeAndClusterIdConverter.java
index a3062bca90158..7bbb83e311adc 100644
--- a/server/src/main/java/org/opensearch/common/logging/NodeAndClusterIdConverter.java
+++ b/server/src/main/java/org/opensearch/common/logging/NodeAndClusterIdConverter.java
@@ -37,7 +37,7 @@
 import org.apache.logging.log4j.core.pattern.ConverterKeys;
 import org.apache.logging.log4j.core.pattern.LogEventPatternConverter;
 import org.apache.logging.log4j.core.pattern.PatternConverter;
-import org.apache.lucene.util.SetOnce;
+import org.opensearch.common.SetOnce;
 
 import java.util.Locale;
 
diff --git a/server/src/main/java/org/opensearch/common/logging/NodeNamePatternConverter.java b/server/src/main/java/org/opensearch/common/logging/NodeNamePatternConverter.java
index bc25f690d4a64..b0ecbb6f9407f 100644
--- a/server/src/main/java/org/opensearch/common/logging/NodeNamePatternConverter.java
+++ b/server/src/main/java/org/opensearch/common/logging/NodeNamePatternConverter.java
@@ -39,7 +39,7 @@
 import org.apache.logging.log4j.core.pattern.ConverterKeys;
 import org.apache.logging.log4j.core.pattern.LogEventPatternConverter;
 import org.apache.logging.log4j.core.pattern.PatternConverter;
-import org.apache.lucene.util.SetOnce;
+import org.opensearch.common.SetOnce;
 
 /**
  * Converts {@code %node_name} in log4j patterns into the current node name.
diff --git a/server/src/main/java/org/opensearch/common/settings/KeyStoreWrapper.java b/server/src/main/java/org/opensearch/common/settings/KeyStoreWrapper.java
index 508e1bc38ea8a..ffd980f8f0da6 100644
--- a/server/src/main/java/org/opensearch/common/settings/KeyStoreWrapper.java
+++ b/server/src/main/java/org/opensearch/common/settings/KeyStoreWrapper.java
@@ -40,10 +40,10 @@
 import org.apache.lucene.store.IOContext;
 import org.apache.lucene.store.IndexOutput;
 import org.apache.lucene.store.NIOFSDirectory;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.cli.ExitCodes;
 import org.opensearch.cli.UserException;
 import org.opensearch.common.Randomness;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.hash.MessageDigests;
 
 import javax.crypto.AEADBadTagException;
diff --git a/server/src/main/java/org/opensearch/common/settings/Settings.java b/server/src/main/java/org/opensearch/common/settings/Settings.java
index 5e15e1693c017..d5ec0e514ac67 100644
--- a/server/src/main/java/org/opensearch/common/settings/Settings.java
+++ b/server/src/main/java/org/opensearch/common/settings/Settings.java
@@ -33,11 +33,11 @@
 package org.opensearch.common.settings;
 
 import org.apache.logging.log4j.Level;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.OpenSearchGenerationException;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.Version;
 import org.opensearch.common.Booleans;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.io.stream.StreamOutput;
diff --git a/server/src/main/java/org/opensearch/common/util/CancellableThreads.java b/server/src/main/java/org/opensearch/common/util/CancellableThreads.java
index bb9ae9502f746..ad7ceff90c55d 100644
--- a/server/src/main/java/org/opensearch/common/util/CancellableThreads.java
+++ b/server/src/main/java/org/opensearch/common/util/CancellableThreads.java
@@ -31,10 +31,10 @@
 
 package org.opensearch.common.util;
 
-import org.apache.lucene.util.SetOnce;
 import org.apache.lucene.util.ThreadInterruptedException;
 import org.opensearch.OpenSearchException;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.io.stream.StreamInput;
 
 import java.io.IOException;
diff --git a/server/src/main/java/org/opensearch/discovery/PeerFinder.java b/server/src/main/java/org/opensearch/discovery/PeerFinder.java
index e8b6c72c512a2..467ed7ed80ea7 100644
--- a/server/src/main/java/org/opensearch/discovery/PeerFinder.java
+++ b/server/src/main/java/org/opensearch/discovery/PeerFinder.java
@@ -36,12 +36,12 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.coordination.PeersResponse;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
diff --git a/server/src/main/java/org/opensearch/discovery/SeedHostsResolver.java b/server/src/main/java/org/opensearch/discovery/SeedHostsResolver.java
index 94e51fe5804ca..14805648c6771 100644
--- a/server/src/main/java/org/opensearch/discovery/SeedHostsResolver.java
+++ b/server/src/main/java/org/opensearch/discovery/SeedHostsResolver.java
@@ -34,7 +34,7 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.apache.lucene.util.SetOnce;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.component.AbstractLifecycleComponent;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
diff --git a/server/src/main/java/org/opensearch/extensions/ExtensionsManager.java b/server/src/main/java/org/opensearch/extensions/ExtensionsManager.java
index 885e4b0e35ee6..ca65215599891 100644
--- a/server/src/main/java/org/opensearch/extensions/ExtensionsManager.java
+++ b/server/src/main/java/org/opensearch/extensions/ExtensionsManager.java
@@ -20,7 +20,9 @@
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionException;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
 import java.util.stream.Collectors;
 
 import org.apache.logging.log4j.LogManager;
@@ -198,7 +200,7 @@ public void initializeServicesAndRestHandler(
      *
      * @param request which was sent by an extension.
      */
-    public ExtensionActionResponse handleTransportRequest(ExtensionActionRequest request) throws InterruptedException {
+    public ExtensionActionResponse handleTransportRequest(ExtensionActionRequest request) throws Exception {
         return extensionTransportActionsHandler.sendTransportRequestToExtension(request);
     }
 
@@ -401,13 +403,17 @@ public String executor() {
                 new InitializeExtensionRequest(transportService.getLocalNode(), extension),
                 initializeExtensionResponseHandler
             );
-            // TODO: make asynchronous
-            inProgressFuture.get(EXTENSION_REQUEST_WAIT_TIMEOUT, TimeUnit.SECONDS);
-        } catch (Exception e) {
-            try {
-                throw e;
-            } catch (Exception e1) {
-                logger.error(e.toString());
+            inProgressFuture.orTimeout(EXTENSION_REQUEST_WAIT_TIMEOUT, TimeUnit.SECONDS).join();
+        } catch (CompletionException e) {
+            if (e.getCause() instanceof TimeoutException) {
+                logger.info("No response from extension to request.");
+            }
+            if (e.getCause() instanceof RuntimeException) {
+                throw (RuntimeException) e.getCause();
+            } else if (e.getCause() instanceof Error) {
+                throw (Error) e.getCause();
+            } else {
+                throw new RuntimeException(e.getCause());
             }
         }
     }
@@ -462,7 +468,7 @@ public void handleResponse(AcknowledgedResponse response) {
 
             @Override
             public void handleException(TransportException exp) {
-
+                inProgressIndexNameFuture.completeExceptionally(exp);
             }
 
             @Override
@@ -506,20 +512,21 @@ public void beforeIndexRemoved(
                                     new IndicesModuleRequest(indexModule),
                                     acknowledgedResponseHandler
                                 );
-                                // TODO: make asynchronous
-                                inProgressIndexNameFuture.get(EXTENSION_REQUEST_WAIT_TIMEOUT, TimeUnit.SECONDS);
-                                logger.info("Received ack response from Extension");
-                            } catch (Exception e) {
-                                try {
-                                    throw e;
-                                } catch (Exception e1) {
-                                    logger.error(e.toString());
-                                }
+                                inProgressIndexNameFuture.whenComplete((r, e) -> {
+                                    if (e != null) {
+                                        inProgressFuture.complete(response);
+                                    } else if (e == null) {
+                                        inProgressFuture.completeExceptionally(e);
+                                    }
+                                });
+                            } catch (Exception ex) {
+                                inProgressFuture.completeExceptionally(ex);
                             }
                         }
                     });
+                } else {
+                    inProgressFuture.complete(response);
                 }
-                inProgressFuture.complete(response);
             }
 
             @Override
@@ -542,14 +549,18 @@ public String executor() {
                 new IndicesModuleRequest(indexModule),
                 indicesModuleResponseHandler
             );
-            // TODO: make asynchronous
-            inProgressFuture.get(EXTENSION_REQUEST_WAIT_TIMEOUT, TimeUnit.SECONDS);
+            inProgressFuture.orTimeout(EXTENSION_REQUEST_WAIT_TIMEOUT, TimeUnit.SECONDS).join();
             logger.info("Received response from Extension");
-        } catch (Exception e) {
-            try {
-                throw e;
-            } catch (Exception e1) {
-                logger.error(e.toString());
+        } catch (CompletionException e) {
+            if (e.getCause() instanceof TimeoutException) {
+                logger.info("No response from extension to request.");
+            }
+            if (e.getCause() instanceof RuntimeException) {
+                throw (RuntimeException) e.getCause();
+            } else if (e.getCause() instanceof Error) {
+                throw (Error) e.getCause();
+            } else {
+                throw new RuntimeException(e.getCause());
             }
         }
     }
diff --git a/server/src/main/java/org/opensearch/extensions/action/ExtensionTransportActionsHandler.java b/server/src/main/java/org/opensearch/extensions/action/ExtensionTransportActionsHandler.java
index ac3ec6630634a..f76fe794b2f84 100644
--- a/server/src/main/java/org/opensearch/extensions/action/ExtensionTransportActionsHandler.java
+++ b/server/src/main/java/org/opensearch/extensions/action/ExtensionTransportActionsHandler.java
@@ -28,8 +28,10 @@
 import java.nio.charset.StandardCharsets;
 import java.util.HashMap;
 import java.util.Map;
-import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionException;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
 
 /**
  * This class manages TransportActions for extensions
@@ -108,10 +110,9 @@ public TransportResponse handleRegisterTransportActionsRequest(RegisterTransport
      * @return {@link TransportResponse} which is sent back to the transport action invoker.
      * @throws InterruptedException when message transport fails.
      */
-    public TransportResponse handleTransportActionRequestFromExtension(TransportActionRequestFromExtension request)
-        throws InterruptedException {
+    public TransportResponse handleTransportActionRequestFromExtension(TransportActionRequestFromExtension request) throws Exception {
         DiscoveryExtensionNode extension = extensionIdMap.get(request.getUniqueId());
-        final CountDownLatch inProgressLatch = new CountDownLatch(1);
+        final CompletableFuture<ExtensionActionResponse> inProgressFuture = new CompletableFuture<>();
         final TransportActionResponseToExtension response = new TransportActionResponseToExtension(new byte[0]);
         client.execute(
             ExtensionProxyAction.INSTANCE,
@@ -120,7 +121,7 @@ public TransportResponse handleTransportActionRequestFromExtension(TransportActi
                 @Override
                 public void onResponse(ExtensionActionResponse actionResponse) {
                     response.setResponseBytes(actionResponse.getResponseBytes());
-                    inProgressLatch.countDown();
+                    inProgressFuture.complete(actionResponse);
                 }
 
                 @Override
@@ -128,11 +129,24 @@ public void onFailure(Exception exp) {
                     logger.debug("Transport request failed", exp);
                     byte[] responseBytes = ("Request failed: " + exp.getMessage()).getBytes(StandardCharsets.UTF_8);
                     response.setResponseBytes(responseBytes);
-                    inProgressLatch.countDown();
+                    inProgressFuture.completeExceptionally(exp);
                 }
             }
         );
-        inProgressLatch.await(ExtensionsManager.EXTENSION_REQUEST_WAIT_TIMEOUT, TimeUnit.SECONDS);
+        try {
+            inProgressFuture.orTimeout(ExtensionsManager.EXTENSION_REQUEST_WAIT_TIMEOUT, TimeUnit.SECONDS).join();
+        } catch (CompletionException e) {
+            if (e.getCause() instanceof TimeoutException) {
+                logger.info("No response from extension to request.");
+            }
+            if (e.getCause() instanceof RuntimeException) {
+                throw (RuntimeException) e.getCause();
+            } else if (e.getCause() instanceof Error) {
+                throw (Error) e.getCause();
+            } else {
+                throw new RuntimeException(e.getCause());
+            }
+        }
         return response;
     }
 
@@ -143,12 +157,12 @@ public void onFailure(Exception exp) {
      * @return {@link ExtensionActionResponse} which encapsulates the transport response from the extension.
      * @throws InterruptedException when message transport fails.
      */
-    public ExtensionActionResponse sendTransportRequestToExtension(ExtensionActionRequest request) throws InterruptedException {
+    public ExtensionActionResponse sendTransportRequestToExtension(ExtensionActionRequest request) throws Exception {
         DiscoveryExtensionNode extension = actionsMap.get(request.getAction());
         if (extension == null) {
             throw new ActionNotFoundTransportException(request.getAction());
         }
-        final CountDownLatch inProgressLatch = new CountDownLatch(1);
+        final CompletableFuture<ExtensionActionResponse> inProgressFuture = new CompletableFuture<>();
         final ExtensionActionResponse extensionActionResponse = new ExtensionActionResponse(new byte[0]);
         final TransportResponseHandler<ExtensionActionResponse> extensionActionResponseTransportResponseHandler =
             new TransportResponseHandler<ExtensionActionResponse>() {
@@ -161,7 +175,7 @@ public ExtensionActionResponse read(StreamInput in) throws IOException {
                 @Override
                 public void handleResponse(ExtensionActionResponse response) {
                     extensionActionResponse.setResponseBytes(response.getResponseBytes());
-                    inProgressLatch.countDown();
+                    inProgressFuture.complete(response);
                 }
 
                 @Override
@@ -169,7 +183,7 @@ public void handleException(TransportException exp) {
                     logger.debug("Transport request failed", exp);
                     byte[] responseBytes = ("Request failed: " + exp.getMessage()).getBytes(StandardCharsets.UTF_8);
                     extensionActionResponse.setResponseBytes(responseBytes);
-                    inProgressLatch.countDown();
+                    inProgressFuture.completeExceptionally(exp);
                 }
 
                 @Override
@@ -187,7 +201,20 @@ public String executor() {
         } catch (Exception e) {
             logger.info("Failed to send transport action to extension " + extension.getName(), e);
         }
-        inProgressLatch.await(ExtensionsManager.EXTENSION_REQUEST_WAIT_TIMEOUT, TimeUnit.SECONDS);
+        try {
+            inProgressFuture.orTimeout(ExtensionsManager.EXTENSION_REQUEST_WAIT_TIMEOUT, TimeUnit.SECONDS).join();
+        } catch (CompletionException e) {
+            if (e.getCause() instanceof TimeoutException) {
+                logger.info("No response from extension to request.");
+            }
+            if (e.getCause() instanceof RuntimeException) {
+                throw (RuntimeException) e.getCause();
+            } else if (e.getCause() instanceof Error) {
+                throw (Error) e.getCause();
+            } else {
+                throw new RuntimeException(e.getCause());
+            }
+        }
         return extensionActionResponse;
     }
 }
diff --git a/server/src/main/java/org/opensearch/extensions/rest/RestSendToExtensionAction.java b/server/src/main/java/org/opensearch/extensions/rest/RestSendToExtensionAction.java
index 38e92ed604a09..357be3a9fc2fe 100644
--- a/server/src/main/java/org/opensearch/extensions/rest/RestSendToExtensionAction.java
+++ b/server/src/main/java/org/opensearch/extensions/rest/RestSendToExtensionAction.java
@@ -32,8 +32,11 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
-import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionException;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+
 import static java.util.Collections.emptyList;
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.unmodifiableList;
@@ -122,7 +125,7 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
             emptyList(),
             false
         );
-        final CountDownLatch inProgressLatch = new CountDownLatch(1);
+        final CompletableFuture<RestExecuteOnExtensionResponse> inProgressFuture = new CompletableFuture<>();
         final TransportResponseHandler<RestExecuteOnExtensionResponse> restExecuteOnExtensionResponseHandler = new TransportResponseHandler<
             RestExecuteOnExtensionResponse>() {
 
@@ -143,15 +146,13 @@ public void handleResponse(RestExecuteOnExtensionResponse response) {
                 if (response.isContentConsumed()) {
                     request.content();
                 }
+                inProgressFuture.complete(response);
             }
 
             @Override
             public void handleException(TransportException exp) {
                 logger.debug("REST request failed", exp);
-                // Status is already defaulted to 500 (INTERNAL_SERVER_ERROR)
-                byte[] responseBytes = ("Request failed: " + exp.getMessage()).getBytes(StandardCharsets.UTF_8);
-                restExecuteOnExtensionResponse.setContent(responseBytes);
-                inProgressLatch.countDown();
+                inProgressFuture.completeExceptionally(exp);
             }
 
             @Override
@@ -172,15 +173,24 @@ public String executor() {
                 new ExtensionRestRequest(method, path, params, contentType, content, requestIssuerIdentity),
                 restExecuteOnExtensionResponseHandler
             );
-            try {
-                inProgressLatch.await(5, TimeUnit.SECONDS);
-            } catch (InterruptedException e) {
+            inProgressFuture.orTimeout(ExtensionsManager.EXTENSION_REQUEST_WAIT_TIMEOUT, TimeUnit.SECONDS).join();
+        } catch (CompletionException e) {
+            Throwable cause = e.getCause();
+            if (cause instanceof TimeoutException) {
                 return channel -> channel.sendResponse(
                     new BytesRestResponse(RestStatus.REQUEST_TIMEOUT, "No response from extension to request.")
                 );
             }
-        } catch (Exception e) {
-            logger.info("Failed to send REST Actions to extension " + discoveryExtensionNode.getName(), e);
+            if (e.getCause() instanceof RuntimeException) {
+                throw (RuntimeException) e.getCause();
+            } else if (e.getCause() instanceof Error) {
+                throw (Error) e.getCause();
+            } else {
+                throw new RuntimeException(e.getCause());
+            }
+        } catch (Exception ex) {
+            logger.info("Failed to send REST Actions to extension " + discoveryExtensionNode.getName(), ex);
+            return channel -> channel.sendResponse(new BytesRestResponse(RestStatus.INTERNAL_SERVER_ERROR, ex.getMessage()));
         }
         BytesRestResponse restResponse = new BytesRestResponse(
             restExecuteOnExtensionResponse.getStatus(),
diff --git a/server/src/main/java/org/opensearch/gateway/GatewayMetaState.java b/server/src/main/java/org/opensearch/gateway/GatewayMetaState.java
index 48dd0ddf90413..ea550fc6ac3e8 100644
--- a/server/src/main/java/org/opensearch/gateway/GatewayMetaState.java
+++ b/server/src/main/java/org/opensearch/gateway/GatewayMetaState.java
@@ -36,7 +36,6 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.store.AlreadyClosedException;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.OpenSearchException;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.Version;
@@ -54,6 +53,7 @@
 import org.opensearch.cluster.metadata.MetadataIndexUpgradeService;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
diff --git a/server/src/main/java/org/opensearch/gateway/PersistedClusterStateService.java b/server/src/main/java/org/opensearch/gateway/PersistedClusterStateService.java
index ea77e4ae5f13b..30af9aaa91765 100644
--- a/server/src/main/java/org/opensearch/gateway/PersistedClusterStateService.java
+++ b/server/src/main/java/org/opensearch/gateway/PersistedClusterStateService.java
@@ -60,13 +60,13 @@
 import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefIterator;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.bytes.RecyclingBytesStreamOutput;
 import org.opensearch.common.io.Streams;
diff --git a/server/src/main/java/org/opensearch/index/IndexModule.java b/server/src/main/java/org/opensearch/index/IndexModule.java
index 5b9b051af8e8b..f2675f018d0e6 100644
--- a/server/src/main/java/org/opensearch/index/IndexModule.java
+++ b/server/src/main/java/org/opensearch/index/IndexModule.java
@@ -40,13 +40,13 @@
 import org.apache.lucene.search.similarities.Similarity;
 import org.apache.lucene.store.MMapDirectory;
 import org.apache.lucene.util.Constants;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.CheckedFunction;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.TriFunction;
 import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.logging.DeprecationLogger;
diff --git a/server/src/main/java/org/opensearch/index/engine/Engine.java b/server/src/main/java/org/opensearch/index/engine/Engine.java
index 95d671ee7adc2..604fa7a53e65c 100644
--- a/server/src/main/java/org/opensearch/index/engine/Engine.java
+++ b/server/src/main/java/org/opensearch/index/engine/Engine.java
@@ -51,10 +51,10 @@
 import org.apache.lucene.store.AlreadyClosedException;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.IOContext;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.concurrent.GatedCloseable;
diff --git a/server/src/main/java/org/opensearch/index/query/AbstractGeometryQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/AbstractGeometryQueryBuilder.java
index 4f0a873ac7bdb..dfffafa7cf114 100644
--- a/server/src/main/java/org/opensearch/index/query/AbstractGeometryQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/AbstractGeometryQueryBuilder.java
@@ -34,7 +34,6 @@
 
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
 import org.opensearch.action.ActionListener;
 import org.opensearch.action.get.GetRequest;
@@ -42,6 +41,7 @@
 import org.opensearch.client.Client;
 import org.opensearch.common.ParseField;
 import org.opensearch.common.ParsingException;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.geo.GeoJson;
 import org.opensearch.common.geo.GeometryIO;
 import org.opensearch.common.geo.GeometryParser;
diff --git a/server/src/main/java/org/opensearch/index/query/QueryShardContext.java b/server/src/main/java/org/opensearch/index/query/QueryShardContext.java
index fe2ed23b2b279..9338b28e5f68d 100644
--- a/server/src/main/java/org/opensearch/index/query/QueryShardContext.java
+++ b/server/src/main/java/org/opensearch/index/query/QueryShardContext.java
@@ -38,12 +38,12 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.join.BitSetProducer;
 import org.apache.lucene.search.similarities.Similarity;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
 import org.opensearch.action.ActionListener;
 import org.opensearch.client.Client;
 import org.opensearch.common.CheckedFunction;
 import org.opensearch.common.ParsingException;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.TriFunction;
 import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.lucene.search.Queries;
diff --git a/server/src/main/java/org/opensearch/index/query/TermsQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/TermsQueryBuilder.java
index 28f98f7060395..a1529889e0d05 100644
--- a/server/src/main/java/org/opensearch/index/query/TermsQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/TermsQueryBuilder.java
@@ -37,11 +37,11 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefBuilder;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.action.ActionListener;
 import org.opensearch.action.get.GetRequest;
 import org.opensearch.client.Client;
 import org.opensearch.common.ParsingException;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.Strings;
 import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
diff --git a/server/src/main/java/org/opensearch/index/shard/IndexShard.java b/server/src/main/java/org/opensearch/index/shard/IndexShard.java
index 26abe80d2bff2..96a54ab65d268 100644
--- a/server/src/main/java/org/opensearch/index/shard/IndexShard.java
+++ b/server/src/main/java/org/opensearch/index/shard/IndexShard.java
@@ -55,7 +55,6 @@
 import org.apache.lucene.store.FilterDirectory;
 import org.apache.lucene.store.IOContext;
 import org.apache.lucene.store.IndexInput;
-import org.apache.lucene.util.SetOnce;
 import org.apache.lucene.util.ThreadInterruptedException;
 import org.opensearch.Assertions;
 import org.opensearch.ExceptionsHelper;
@@ -80,6 +79,7 @@
 import org.opensearch.common.CheckedFunction;
 import org.opensearch.common.CheckedRunnable;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.concurrent.GatedCloseable;
 import org.opensearch.common.io.stream.BytesStreamOutput;
diff --git a/server/src/main/java/org/opensearch/index/translog/transfer/TranslogTransferMetadata.java b/server/src/main/java/org/opensearch/index/translog/transfer/TranslogTransferMetadata.java
index 243294d85c97d..3b2884dca9a3f 100644
--- a/server/src/main/java/org/opensearch/index/translog/transfer/TranslogTransferMetadata.java
+++ b/server/src/main/java/org/opensearch/index/translog/transfer/TranslogTransferMetadata.java
@@ -12,7 +12,7 @@
 import org.apache.lucene.store.DataOutput;
 import org.apache.lucene.store.IndexInput;
 import org.apache.lucene.store.OutputStreamIndexOutput;
-import org.apache.lucene.util.SetOnce;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 
diff --git a/server/src/main/java/org/opensearch/indices/recovery/LocalStorePeerRecoverySourceHandler.java b/server/src/main/java/org/opensearch/indices/recovery/LocalStorePeerRecoverySourceHandler.java
index 4bb6fc1d23b9f..c8d3b2d09ad28 100644
--- a/server/src/main/java/org/opensearch/indices/recovery/LocalStorePeerRecoverySourceHandler.java
+++ b/server/src/main/java/org/opensearch/indices/recovery/LocalStorePeerRecoverySourceHandler.java
@@ -9,13 +9,13 @@
 package org.opensearch.indices.recovery;
 
 import org.apache.lucene.index.IndexCommit;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.action.ActionListener;
 import org.opensearch.action.StepListener;
 import org.opensearch.action.support.ThreadedActionListener;
 import org.opensearch.action.support.replication.ReplicationResponse;
 import org.opensearch.cluster.routing.IndexShardRoutingTable;
 import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.concurrent.GatedCloseable;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.unit.TimeValue;
diff --git a/server/src/main/java/org/opensearch/node/Node.java b/server/src/main/java/org/opensearch/node/Node.java
index ab39a7bf71ff6..662a44a81ef85 100644
--- a/server/src/main/java/org/opensearch/node/Node.java
+++ b/server/src/main/java/org/opensearch/node/Node.java
@@ -35,7 +35,7 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.util.Constants;
-import org.apache.lucene.util.SetOnce;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.cluster.routing.allocation.AwarenessReplicaBalance;
 import org.opensearch.index.IndexModule;
diff --git a/server/src/main/java/org/opensearch/repositories/blobstore/BlobStoreRepository.java b/server/src/main/java/org/opensearch/repositories/blobstore/BlobStoreRepository.java
index d2a70e88d6eee..9113c5531b1e3 100644
--- a/server/src/main/java/org/opensearch/repositories/blobstore/BlobStoreRepository.java
+++ b/server/src/main/java/org/opensearch/repositories/blobstore/BlobStoreRepository.java
@@ -45,7 +45,6 @@
 import org.apache.lucene.store.IndexOutput;
 import org.apache.lucene.store.RateLimiter;
 import org.apache.lucene.util.BytesRef;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.Version;
 import org.opensearch.action.ActionListener;
@@ -67,6 +66,7 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.Numbers;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.blobstore.BlobContainer;
diff --git a/server/src/main/java/org/opensearch/rest/RestRequest.java b/server/src/main/java/org/opensearch/rest/RestRequest.java
index d44a4e3039543..1e0a2b1827e10 100644
--- a/server/src/main/java/org/opensearch/rest/RestRequest.java
+++ b/server/src/main/java/org/opensearch/rest/RestRequest.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.rest;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.common.Booleans;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.Strings;
 import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.bytes.BytesReference;
diff --git a/server/src/main/java/org/opensearch/search/aggregations/Aggregations.java b/server/src/main/java/org/opensearch/search/aggregations/Aggregations.java
index 4049d96d68817..b59eaa46f0bd1 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/Aggregations.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/Aggregations.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.search.aggregations;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.common.ParsingException;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.xcontent.ToXContentFragment;
 import org.opensearch.common.xcontent.XContentBuilder;
 import org.opensearch.common.xcontent.XContentParser;
diff --git a/server/src/main/java/org/opensearch/search/internal/PitReaderContext.java b/server/src/main/java/org/opensearch/search/internal/PitReaderContext.java
index b24a8a4172e29..5c2a9f82f98e4 100644
--- a/server/src/main/java/org/opensearch/search/internal/PitReaderContext.java
+++ b/server/src/main/java/org/opensearch/search/internal/PitReaderContext.java
@@ -8,8 +8,8 @@
 
 package org.opensearch.search.internal;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.cluster.routing.ShardRouting;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.index.IndexService;
diff --git a/server/src/main/java/org/opensearch/search/suggest/Suggest.java b/server/src/main/java/org/opensearch/search/suggest/Suggest.java
index 0aa881e2a3c9e..7943892b2af89 100644
--- a/server/src/main/java/org/opensearch/search/suggest/Suggest.java
+++ b/server/src/main/java/org/opensearch/search/suggest/Suggest.java
@@ -32,10 +32,10 @@
 package org.opensearch.search.suggest;
 
 import org.apache.lucene.util.CollectionUtil;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.common.CheckedFunction;
 import org.opensearch.common.ParseField;
 import org.opensearch.common.ParsingException;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.NamedWriteable;
 import org.opensearch.common.io.stream.StreamInput;
diff --git a/server/src/main/java/org/opensearch/tasks/TaskManager.java b/server/src/main/java/org/opensearch/tasks/TaskManager.java
index 334cde81dfb6a..ff760219716e6 100644
--- a/server/src/main/java/org/opensearch/tasks/TaskManager.java
+++ b/server/src/main/java/org/opensearch/tasks/TaskManager.java
@@ -37,7 +37,6 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Assertions;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.OpenSearchException;
@@ -49,6 +48,7 @@
 import org.opensearch.cluster.ClusterStateApplier;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.lease.Releasables;
 import org.opensearch.common.settings.ClusterSettings;
diff --git a/server/src/main/java/org/opensearch/transport/SniffConnectionStrategy.java b/server/src/main/java/org/opensearch/transport/SniffConnectionStrategy.java
index 47fd5fc2c9489..d465f05cd6a6f 100644
--- a/server/src/main/java/org/opensearch/transport/SniffConnectionStrategy.java
+++ b/server/src/main/java/org/opensearch/transport/SniffConnectionStrategy.java
@@ -33,7 +33,6 @@
 package org.opensearch.transport;
 
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
 import org.opensearch.action.ActionListener;
 import org.opensearch.action.StepListener;
@@ -44,6 +43,7 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.common.Booleans;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.Strings;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.io.stream.StreamInput;
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/configuration/TransportAddVotingConfigExclusionsActionTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/configuration/TransportAddVotingConfigExclusionsActionTests.java
index 69570fa7b4640..03c6b5ab822c1 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/configuration/TransportAddVotingConfigExclusionsActionTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/configuration/TransportAddVotingConfigExclusionsActionTests.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.action.admin.cluster.configuration;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.OpenSearchTimeoutException;
 import org.opensearch.Version;
 import org.opensearch.action.support.ActionFilters;
@@ -49,6 +48,7 @@
 import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.cluster.node.DiscoveryNodes.Builder;
 import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.ClusterSettings;
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/configuration/TransportClearVotingConfigExclusionsActionTests.java b/server/src/test/java/org/opensearch/action/admin/cluster/configuration/TransportClearVotingConfigExclusionsActionTests.java
index b3620bf757256..37ead5d588f84 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/configuration/TransportClearVotingConfigExclusionsActionTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/configuration/TransportClearVotingConfigExclusionsActionTests.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.action.admin.cluster.configuration;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.OpenSearchTimeoutException;
 import org.opensearch.Version;
 import org.opensearch.action.support.ActionFilters;
@@ -45,6 +44,7 @@
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.cluster.node.DiscoveryNodes.Builder;
 import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
diff --git a/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TaskManagerTestCase.java b/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TaskManagerTestCase.java
index 8b0c2187d05af..4eba00e95b77c 100644
--- a/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TaskManagerTestCase.java
+++ b/server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TaskManagerTestCase.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.action.admin.cluster.node.tasks;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
 import org.opensearch.action.FailedNodeException;
 import org.opensearch.action.admin.cluster.node.tasks.cancel.TransportCancelTasksAction;
@@ -46,6 +45,7 @@
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.io.stream.StreamOutput;
diff --git a/server/src/test/java/org/opensearch/action/admin/indices/close/TransportVerifyShardBeforeCloseActionTests.java b/server/src/test/java/org/opensearch/action/admin/indices/close/TransportVerifyShardBeforeCloseActionTests.java
index 000dac92506f6..f617585894766 100644
--- a/server/src/test/java/org/opensearch/action/admin/indices/close/TransportVerifyShardBeforeCloseActionTests.java
+++ b/server/src/test/java/org/opensearch/action/admin/indices/close/TransportVerifyShardBeforeCloseActionTests.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.action.admin.indices.close;
 
-import org.apache.lucene.util.SetOnce;
 import org.junit.After;
 import org.junit.AfterClass;
 import org.junit.Before;
@@ -59,6 +58,7 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.index.shard.IndexShard;
diff --git a/server/src/test/java/org/opensearch/action/search/TransportSearchActionTests.java b/server/src/test/java/org/opensearch/action/search/TransportSearchActionTests.java
index d1f2304365d59..136e1879881f8 100644
--- a/server/src/test/java/org/opensearch/action/search/TransportSearchActionTests.java
+++ b/server/src/test/java/org/opensearch/action/search/TransportSearchActionTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.action.search;
 
 import org.apache.lucene.search.TotalHits;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
 import org.opensearch.action.ActionListener;
 import org.opensearch.action.LatchedActionListener;
@@ -52,6 +51,7 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.routing.TestShardRouting;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.Strings;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
diff --git a/server/src/test/java/org/opensearch/action/support/replication/TransportReplicationAllPermitsAcquisitionTests.java b/server/src/test/java/org/opensearch/action/support/replication/TransportReplicationAllPermitsAcquisitionTests.java
index 98972d4063a97..013be1f2ebd42 100644
--- a/server/src/test/java/org/opensearch/action/support/replication/TransportReplicationAllPermitsAcquisitionTests.java
+++ b/server/src/test/java/org/opensearch/action/support/replication/TransportReplicationAllPermitsAcquisitionTests.java
@@ -31,7 +31,6 @@
 
 package org.opensearch.action.support.replication;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
 import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.ActionFilters;
@@ -54,6 +53,7 @@
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.ShardRoutingState;
 import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.lease.Releasable;
 import org.opensearch.common.settings.Settings;
diff --git a/server/src/test/java/org/opensearch/cluster/action/shard/ShardStateActionTests.java b/server/src/test/java/org/opensearch/cluster/action/shard/ShardStateActionTests.java
index 2138f28f7b8c2..95ef12f0224fd 100644
--- a/server/src/test/java/org/opensearch/cluster/action/shard/ShardStateActionTests.java
+++ b/server/src/test/java/org/opensearch/cluster/action/shard/ShardStateActionTests.java
@@ -33,7 +33,6 @@
 package org.opensearch.cluster.action.shard;
 
 import org.apache.lucene.index.CorruptIndexException;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
 import org.opensearch.action.ActionListener;
 import org.opensearch.action.support.replication.ClusterStateCreationUtils;
@@ -51,6 +50,7 @@
 import org.opensearch.cluster.routing.ShardsIterator;
 import org.opensearch.cluster.routing.allocation.AllocationService;
 import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.io.stream.StreamInput;
diff --git a/server/src/test/java/org/opensearch/cluster/routing/allocation/DiskThresholdMonitorTests.java b/server/src/test/java/org/opensearch/cluster/routing/allocation/DiskThresholdMonitorTests.java
index 9f3f603e8edf3..4c4b362ef7c56 100644
--- a/server/src/test/java/org/opensearch/cluster/routing/allocation/DiskThresholdMonitorTests.java
+++ b/server/src/test/java/org/opensearch/cluster/routing/allocation/DiskThresholdMonitorTests.java
@@ -129,6 +129,11 @@ protected void updateIndicesReadOnly(Set<String> indicesToMarkReadOnly, ActionLi
                 assertTrue(readOnly);
                 listener.onResponse(null);
             }
+
+            @Override
+            protected void setIndexCreateBlock(ActionListener<Void> listener, boolean indexCreateBlock) {
+                listener.onResponse(null);
+            }
         };
 
         ImmutableOpenMap.Builder<String, DiskUsage> builder = ImmutableOpenMap.builder();
@@ -185,6 +190,11 @@ protected void updateIndicesReadOnly(Set<String> indicesToMarkReadOnly, ActionLi
                 assertTrue(readOnly);
                 listener.onResponse(null);
             }
+
+            @Override
+            protected void setIndexCreateBlock(ActionListener<Void> listener, boolean indexCreateBlock) {
+                listener.onResponse(null);
+            }
         };
 
         indices.set(null);
@@ -372,6 +382,12 @@ protected void updateIndicesReadOnly(Set<String> indicesToUpdate, ActionListener
                 }
                 listener.onResponse(null);
             }
+
+            @Override
+            protected void setIndexCreateBlock(ActionListener<Void> listener, boolean indexCreateBlock) {
+                listener.onResponse(null);
+            }
+
         };
         indicesToMarkReadOnly.set(null);
         indicesToRelease.set(null);
@@ -428,6 +444,11 @@ protected void updateIndicesReadOnly(Set<String> indicesToUpdate, ActionListener
                 }
                 listener.onResponse(null);
             }
+
+            @Override
+            protected void setIndexCreateBlock(ActionListener<Void> listener, boolean indexCreateBlock) {
+                listener.onResponse(null);
+            }
         };
         // When free disk on any of node1 or node2 goes below 5% flood watermark, then apply index block on indices not having the block
         indicesToMarkReadOnly.set(null);
@@ -536,6 +557,11 @@ protected void updateIndicesReadOnly(Set<String> indicesToMarkReadOnly, ActionLi
             long sizeOfRelocatingShards(RoutingNode routingNode, DiskUsage diskUsage, ClusterInfo info, ClusterState reroutedClusterState) {
                 return relocatingShardSizeRef.get();
             }
+
+            @Override
+            protected void setIndexCreateBlock(ActionListener<Void> listener, boolean indexCreateBlock) {
+                listener.onResponse(null);
+            }
         };
 
         final ImmutableOpenMap.Builder<String, DiskUsage> allDisksOkBuilder;
diff --git a/server/src/test/java/org/opensearch/common/xcontent/XContentParserUtilsTests.java b/server/src/test/java/org/opensearch/common/xcontent/XContentParserUtilsTests.java
index aafe77a895dbc..36c08d11d424f 100644
--- a/server/src/test/java/org/opensearch/common/xcontent/XContentParserUtilsTests.java
+++ b/server/src/test/java/org/opensearch/common/xcontent/XContentParserUtilsTests.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.common.xcontent;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.common.CheckedBiConsumer;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.ParseField;
 import org.opensearch.common.ParsingException;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.xcontent.json.JsonXContent;
diff --git a/server/src/test/java/org/opensearch/discovery/HandshakingTransportAddressConnectorTests.java b/server/src/test/java/org/opensearch/discovery/HandshakingTransportAddressConnectorTests.java
index 3a1c24806e266..5d252168c7b28 100644
--- a/server/src/test/java/org/opensearch/discovery/HandshakingTransportAddressConnectorTests.java
+++ b/server/src/test/java/org/opensearch/discovery/HandshakingTransportAddressConnectorTests.java
@@ -35,13 +35,13 @@
 import org.apache.logging.log4j.Level;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.OpenSearchException;
 import org.opensearch.Version;
 import org.opensearch.action.ActionListener;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.test.OpenSearchTestCase;
diff --git a/server/src/test/java/org/opensearch/extensions/ExtensionsManagerTests.java b/server/src/test/java/org/opensearch/extensions/ExtensionsManagerTests.java
index 44cf3a38f01d1..5de2113672ca5 100644
--- a/server/src/test/java/org/opensearch/extensions/ExtensionsManagerTests.java
+++ b/server/src/test/java/org/opensearch/extensions/ExtensionsManagerTests.java
@@ -84,6 +84,8 @@
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.ConnectTransportException;
+import org.opensearch.transport.NodeNotConnectedException;
 import org.opensearch.transport.Transport;
 import org.opensearch.transport.TransportResponse;
 import org.opensearch.transport.TransportService;
@@ -427,23 +429,23 @@ public void testInitialize() throws Exception {
 
             mockLogAppender.addExpectation(
                 new MockLogAppender.SeenEventExpectation(
-                    "Connect Transport Exception 1",
+                    "Node Not Connected Exception 1",
                     "org.opensearch.extensions.ExtensionsManager",
                     Level.ERROR,
-                    "ConnectTransportException[[firstExtension][127.0.0.0:9300] connect_timeout[30s]]"
+                    "[secondExtension][127.0.0.1:9301] Node not connected"
                 )
             );
 
             mockLogAppender.addExpectation(
                 new MockLogAppender.SeenEventExpectation(
-                    "Connect Transport Exception 2",
+                    "Node Not Connected Exception 2",
                     "org.opensearch.extensions.ExtensionsManager",
                     Level.ERROR,
-                    "ConnectTransportException[[secondExtension][127.0.0.1:9301] connect_exception]; nested: ConnectException[Connection refused];"
+                    "[firstExtension][127.0.0.0:9300] Node not connected"
                 )
             );
 
-            extensionsManager.initialize();
+            expectThrows(ConnectTransportException.class, () -> extensionsManager.initialize());
 
             // Test needs to be changed to mock the connection between the local node and an extension. Assert statment is commented out for
             // now.
@@ -831,21 +833,8 @@ public void testOnIndexModule() throws Exception {
             new IndexNameExpressionResolver(new ThreadContext(Settings.EMPTY)),
             Collections.emptyMap()
         );
+        expectThrows(NodeNotConnectedException.class, () -> extensionsManager.onIndexModule(indexModule));
 
-        try (MockLogAppender mockLogAppender = MockLogAppender.createForLoggers(LogManager.getLogger(ExtensionsManager.class))) {
-
-            mockLogAppender.addExpectation(
-                new MockLogAppender.SeenEventExpectation(
-                    "IndicesModuleRequest Failure",
-                    "org.opensearch.extensions.ExtensionsManager",
-                    Level.ERROR,
-                    "IndicesModuleRequest failed"
-                )
-            );
-
-            extensionsManager.onIndexModule(indexModule);
-            mockLogAppender.assertAllExpectationsMatched();
-        }
     }
 
     private void initialize(ExtensionsManager extensionsManager) {
diff --git a/server/src/test/java/org/opensearch/extensions/action/ExtensionTransportActionsHandlerTests.java b/server/src/test/java/org/opensearch/extensions/action/ExtensionTransportActionsHandlerTests.java
index c3d6372a4f6b8..276e47d7f55a8 100644
--- a/server/src/test/java/org/opensearch/extensions/action/ExtensionTransportActionsHandlerTests.java
+++ b/server/src/test/java/org/opensearch/extensions/action/ExtensionTransportActionsHandlerTests.java
@@ -31,6 +31,7 @@
 import org.opensearch.threadpool.TestThreadPool;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.ActionNotFoundTransportException;
+import org.opensearch.transport.NodeNotConnectedException;
 import org.opensearch.transport.TransportService;
 import org.opensearch.transport.nio.MockNioTransport;
 
@@ -172,10 +173,6 @@ public void testSendTransportRequestToExtension() throws InterruptedException {
         );
         assertTrue(response.getStatus());
 
-        ExtensionActionResponse extensionResponse = extensionTransportActionsHandler.sendTransportRequestToExtension(request);
-        assertEquals(
-            "Request failed: [firstExtension][127.0.0.0:9300] Node not connected",
-            new String(extensionResponse.getResponseBytes(), StandardCharsets.UTF_8)
-        );
+        expectThrows(NodeNotConnectedException.class, () -> extensionTransportActionsHandler.sendTransportRequestToExtension(request));
     }
 }
diff --git a/server/src/test/java/org/opensearch/index/IndexModuleTests.java b/server/src/test/java/org/opensearch/index/IndexModuleTests.java
index d2374e767639c..565ae5a16a384 100644
--- a/server/src/test/java/org/opensearch/index/IndexModuleTests.java
+++ b/server/src/test/java/org/opensearch/index/IndexModuleTests.java
@@ -44,8 +44,6 @@
 import org.apache.lucene.search.similarities.BM25Similarity;
 import org.apache.lucene.search.similarities.Similarity;
 import org.apache.lucene.store.Directory;
-import org.apache.lucene.util.SetOnce;
-import org.apache.lucene.util.SetOnce.AlreadySetException;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
@@ -55,6 +53,8 @@
 import org.opensearch.cluster.routing.UnassignedInfo;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.CheckedFunction;
+import org.opensearch.common.SetOnce;
+import org.opensearch.common.SetOnce.AlreadySetException;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.breaker.CircuitBreaker;
 import org.opensearch.common.settings.Setting;
diff --git a/server/src/test/java/org/opensearch/index/engine/InternalEngineTests.java b/server/src/test/java/org/opensearch/index/engine/InternalEngineTests.java
index 878e01c4130bf..c635c708e3b52 100644
--- a/server/src/test/java/org/opensearch/index/engine/InternalEngineTests.java
+++ b/server/src/test/java/org/opensearch/index/engine/InternalEngineTests.java
@@ -80,7 +80,6 @@
 import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.FixedBitSet;
-import org.apache.lucene.util.SetOnce;
 import org.hamcrest.MatcherAssert;
 import org.hamcrest.Matchers;
 import org.opensearch.OpenSearchException;
@@ -96,6 +95,7 @@
 import org.opensearch.common.CheckedBiConsumer;
 import org.opensearch.common.CheckedRunnable;
 import org.opensearch.common.Randomness;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.Strings;
 import org.opensearch.common.TriFunction;
 import org.opensearch.common.UUIDs;
diff --git a/server/src/test/java/org/opensearch/index/fielddata/IndexFieldDataServiceTests.java b/server/src/test/java/org/opensearch/index/fielddata/IndexFieldDataServiceTests.java
index d2f9125be996a..d6fd079ac59e8 100644
--- a/server/src/test/java/org/opensearch/index/fielddata/IndexFieldDataServiceTests.java
+++ b/server/src/test/java/org/opensearch/index/fielddata/IndexFieldDataServiceTests.java
@@ -43,7 +43,7 @@
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.store.ByteBuffersDirectory;
 import org.apache.lucene.util.Accountable;
-import org.apache.lucene.util.SetOnce;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.index.IndexService;
diff --git a/server/src/test/java/org/opensearch/index/query/RewriteableTests.java b/server/src/test/java/org/opensearch/index/query/RewriteableTests.java
index eba4e11881aee..6385a57f9f370 100644
--- a/server/src/test/java/org/opensearch/index/query/RewriteableTests.java
+++ b/server/src/test/java/org/opensearch/index/query/RewriteableTests.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.index.query;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.action.support.PlainActionFuture;
+import org.opensearch.common.SetOnce;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
diff --git a/server/src/test/java/org/opensearch/indices/IndexingMemoryControllerTests.java b/server/src/test/java/org/opensearch/indices/IndexingMemoryControllerTests.java
index be9a3b094ad7c..7a362ce8ded74 100644
--- a/server/src/test/java/org/opensearch/indices/IndexingMemoryControllerTests.java
+++ b/server/src/test/java/org/opensearch/indices/IndexingMemoryControllerTests.java
@@ -32,9 +32,9 @@
 package org.opensearch.indices;
 
 import org.apache.lucene.search.ReferenceManager;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
 import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.ByteSizeUnit;
 import org.opensearch.common.unit.ByteSizeValue;
diff --git a/server/src/test/java/org/opensearch/indices/recovery/LocalStorePeerRecoverySourceHandlerTests.java b/server/src/test/java/org/opensearch/indices/recovery/LocalStorePeerRecoverySourceHandlerTests.java
index 0f5bba4f0c332..ba54d3eb3dba8 100644
--- a/server/src/test/java/org/opensearch/indices/recovery/LocalStorePeerRecoverySourceHandlerTests.java
+++ b/server/src/test/java/org/opensearch/indices/recovery/LocalStorePeerRecoverySourceHandlerTests.java
@@ -45,7 +45,6 @@
 import org.apache.lucene.tests.store.BaseDirectoryWrapper;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.IOContext;
-import org.apache.lucene.util.SetOnce;
 import org.junit.After;
 import org.junit.Before;
 import org.opensearch.ExceptionsHelper;
@@ -58,6 +57,7 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Numbers;
 import org.opensearch.common.Randomness;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.UUIDs;
 import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.bytes.BytesReference;
diff --git a/server/src/test/java/org/opensearch/ingest/IngestServiceTests.java b/server/src/test/java/org/opensearch/ingest/IngestServiceTests.java
index fcd15e85979f7..323f108d18a64 100644
--- a/server/src/test/java/org/opensearch/ingest/IngestServiceTests.java
+++ b/server/src/test/java/org/opensearch/ingest/IngestServiceTests.java
@@ -34,7 +34,6 @@
 
 import org.apache.logging.log4j.Level;
 import org.apache.logging.log4j.LogManager;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.OpenSearchParseException;
 import org.opensearch.ResourceNotFoundException;
 import org.opensearch.Version;
@@ -57,6 +56,7 @@
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.service.ClusterService;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.OpenSearchExecutors;
diff --git a/server/src/test/java/org/opensearch/node/NodeTests.java b/server/src/test/java/org/opensearch/node/NodeTests.java
index 783fe1abdca17..d775a6f645e61 100644
--- a/server/src/test/java/org/opensearch/node/NodeTests.java
+++ b/server/src/test/java/org/opensearch/node/NodeTests.java
@@ -32,10 +32,10 @@
 package org.opensearch.node;
 
 import org.apache.lucene.tests.util.LuceneTestCase;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.bootstrap.BootstrapCheck;
 import org.opensearch.bootstrap.BootstrapContext;
 import org.opensearch.cluster.ClusterName;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.breaker.CircuitBreaker;
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.settings.Settings;
diff --git a/server/src/test/java/org/opensearch/rest/action/document/RestBulkActionTests.java b/server/src/test/java/org/opensearch/rest/action/document/RestBulkActionTests.java
index 19fd74aa30c07..1e13b365c82e3 100644
--- a/server/src/test/java/org/opensearch/rest/action/document/RestBulkActionTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/document/RestBulkActionTests.java
@@ -32,13 +32,13 @@
 
 package org.opensearch.rest.action.document;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
 import org.opensearch.action.ActionListener;
 import org.opensearch.action.bulk.BulkRequest;
 import org.opensearch.action.bulk.BulkResponse;
 import org.opensearch.action.update.UpdateRequest;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.rest.RestChannel;
diff --git a/server/src/test/java/org/opensearch/rest/action/document/RestIndexActionTests.java b/server/src/test/java/org/opensearch/rest/action/document/RestIndexActionTests.java
index 85e5497975888..fac1b2c75c9b7 100644
--- a/server/src/test/java/org/opensearch/rest/action/document/RestIndexActionTests.java
+++ b/server/src/test/java/org/opensearch/rest/action/document/RestIndexActionTests.java
@@ -32,7 +32,6 @@
 
 package org.opensearch.rest.action.document;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.index.IndexRequest;
@@ -40,6 +39,7 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.rest.RestRequest;
diff --git a/server/src/test/java/org/opensearch/search/aggregations/AggregatorFactoriesTests.java b/server/src/test/java/org/opensearch/search/aggregations/AggregatorFactoriesTests.java
index 17abfbf489916..30db12f858c53 100644
--- a/server/src/test/java/org/opensearch/search/aggregations/AggregatorFactoriesTests.java
+++ b/server/src/test/java/org/opensearch/search/aggregations/AggregatorFactoriesTests.java
@@ -31,9 +31,9 @@
 
 package org.opensearch.search.aggregations;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.action.ActionListener;
 import org.opensearch.common.ParsingException;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.Strings;
 import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.StreamOutput;
diff --git a/server/src/test/java/org/opensearch/search/pit/RestCreatePitActionTests.java b/server/src/test/java/org/opensearch/search/pit/RestCreatePitActionTests.java
index 5ca384daedbff..2ddd6eda122b4 100644
--- a/server/src/test/java/org/opensearch/search/pit/RestCreatePitActionTests.java
+++ b/server/src/test/java/org/opensearch/search/pit/RestCreatePitActionTests.java
@@ -8,11 +8,11 @@
 
 package org.opensearch.search.pit;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.action.ActionListener;
 import org.opensearch.action.search.CreatePitRequest;
 import org.opensearch.action.search.CreatePitResponse;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.SetOnce;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.search.RestCreatePitAction;
 import org.opensearch.test.OpenSearchTestCase;
diff --git a/server/src/test/java/org/opensearch/search/pit/RestDeletePitActionTests.java b/server/src/test/java/org/opensearch/search/pit/RestDeletePitActionTests.java
index 0bfa16aafe1e3..c54cf5b5395ce 100644
--- a/server/src/test/java/org/opensearch/search/pit/RestDeletePitActionTests.java
+++ b/server/src/test/java/org/opensearch/search/pit/RestDeletePitActionTests.java
@@ -8,11 +8,11 @@
 
 package org.opensearch.search.pit;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.action.ActionListener;
 import org.opensearch.action.search.DeletePitRequest;
 import org.opensearch.action.search.DeletePitResponse;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.rest.RestRequest;
diff --git a/server/src/test/java/org/opensearch/search/scroll/RestClearScrollActionTests.java b/server/src/test/java/org/opensearch/search/scroll/RestClearScrollActionTests.java
index 065635eff672d..a4605521634fc 100644
--- a/server/src/test/java/org/opensearch/search/scroll/RestClearScrollActionTests.java
+++ b/server/src/test/java/org/opensearch/search/scroll/RestClearScrollActionTests.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.search.scroll;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.action.ActionListener;
 import org.opensearch.action.search.ClearScrollRequest;
 import org.opensearch.action.search.ClearScrollResponse;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.rest.RestRequest;
diff --git a/server/src/test/java/org/opensearch/search/scroll/RestSearchScrollActionTests.java b/server/src/test/java/org/opensearch/search/scroll/RestSearchScrollActionTests.java
index 9e5c74be47525..7db3714769bcc 100644
--- a/server/src/test/java/org/opensearch/search/scroll/RestSearchScrollActionTests.java
+++ b/server/src/test/java/org/opensearch/search/scroll/RestSearchScrollActionTests.java
@@ -32,11 +32,11 @@
 
 package org.opensearch.search.scroll;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.action.ActionListener;
 import org.opensearch.action.search.SearchResponse;
 import org.opensearch.action.search.SearchScrollRequest;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.rest.RestRequest;
diff --git a/server/src/test/java/org/opensearch/snapshots/SnapshotResiliencyTests.java b/server/src/test/java/org/opensearch/snapshots/SnapshotResiliencyTests.java
index 415a3d487b790..a6677fbc0c99b 100644
--- a/server/src/test/java/org/opensearch/snapshots/SnapshotResiliencyTests.java
+++ b/server/src/test/java/org/opensearch/snapshots/SnapshotResiliencyTests.java
@@ -34,7 +34,6 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.ExceptionsHelper;
 import org.opensearch.Version;
 import org.opensearch.action.ActionListener;
@@ -149,6 +148,7 @@
 import org.opensearch.cluster.service.FakeThreadPoolClusterManagerService;
 import org.opensearch.common.CheckedConsumer;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.settings.ClusterSettings;
diff --git a/server/src/test/java/org/opensearch/transport/TransportRequestDeduplicatorTests.java b/server/src/test/java/org/opensearch/transport/TransportRequestDeduplicatorTests.java
index 755459ca96d90..8b4a75a37317b 100644
--- a/server/src/test/java/org/opensearch/transport/TransportRequestDeduplicatorTests.java
+++ b/server/src/test/java/org/opensearch/transport/TransportRequestDeduplicatorTests.java
@@ -31,8 +31,8 @@
 
 package org.opensearch.transport;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.action.ActionListener;
+import org.opensearch.common.SetOnce;
 import org.opensearch.tasks.TaskId;
 import org.opensearch.test.OpenSearchTestCase;
 
diff --git a/test/framework/src/main/java/org/opensearch/index/mapper/MapperTestCase.java b/test/framework/src/main/java/org/opensearch/index/mapper/MapperTestCase.java
index a64193e55836d..c00a3831c0d8d 100644
--- a/test/framework/src/main/java/org/opensearch/index/mapper/MapperTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/index/mapper/MapperTestCase.java
@@ -42,8 +42,8 @@
 import org.apache.lucene.search.NormsFieldExistsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermQuery;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.common.CheckedConsumer;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.Strings;
 import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.xcontent.ToXContent;
diff --git a/test/framework/src/main/java/org/opensearch/repositories/blobstore/OpenSearchBlobStoreRepositoryIntegTestCase.java b/test/framework/src/main/java/org/opensearch/repositories/blobstore/OpenSearchBlobStoreRepositoryIntegTestCase.java
index c5f4e171e0cf2..4fe9f354d8d10 100644
--- a/test/framework/src/main/java/org/opensearch/repositories/blobstore/OpenSearchBlobStoreRepositoryIntegTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/repositories/blobstore/OpenSearchBlobStoreRepositoryIntegTestCase.java
@@ -33,7 +33,6 @@
 
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefBuilder;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotRequestBuilder;
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
@@ -42,6 +41,7 @@
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.client.Client;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.blobstore.BlobContainer;
 import org.opensearch.common.blobstore.BlobMetadata;
 import org.opensearch.common.blobstore.BlobPath;
diff --git a/test/framework/src/main/java/org/opensearch/test/InternalAggregationTestCase.java b/test/framework/src/main/java/org/opensearch/test/InternalAggregationTestCase.java
index 2cba15f2e2039..921fd64d3acb6 100644
--- a/test/framework/src/main/java/org/opensearch/test/InternalAggregationTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/InternalAggregationTestCase.java
@@ -32,8 +32,8 @@
 
 package org.opensearch.test;
 
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.common.ParseField;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.breaker.CircuitBreaker;
 import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.NamedWriteableRegistry;
diff --git a/test/framework/src/main/java/org/opensearch/test/OpenSearchIntegTestCase.java b/test/framework/src/main/java/org/opensearch/test/OpenSearchIntegTestCase.java
index ee6b6ab37423e..86123012fee5d 100644
--- a/test/framework/src/main/java/org/opensearch/test/OpenSearchIntegTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/OpenSearchIntegTestCase.java
@@ -1882,7 +1882,8 @@ protected Settings nodeSettings(int nodeOrdinal) {
             // randomly enable low-level search cancellation to make sure it does not alter results
             .put(SearchService.LOW_LEVEL_CANCELLATION_SETTING.getKey(), randomBoolean())
             .putList(DISCOVERY_SEED_HOSTS_SETTING.getKey()) // empty list disables a port scan for other nodes
-            .putList(DISCOVERY_SEED_PROVIDERS_SETTING.getKey(), "file");
+            .putList(DISCOVERY_SEED_PROVIDERS_SETTING.getKey(), "file")
+            .put(featureFlagSettings());
         return builder.build();
     }
 
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/OpenSearchRestTestCase.java b/test/framework/src/main/java/org/opensearch/test/rest/OpenSearchRestTestCase.java
index a353f53ab1bb3..4fbf56babea29 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/OpenSearchRestTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/OpenSearchRestTestCase.java
@@ -47,7 +47,6 @@
 import org.apache.hc.core5.reactor.ssl.TlsDetails;
 import org.apache.hc.core5.ssl.SSLContexts;
 import org.apache.hc.core5.util.Timeout;
-import org.apache.lucene.util.SetOnce;
 import org.opensearch.Version;
 import org.opensearch.action.admin.cluster.node.tasks.list.ListTasksAction;
 import org.opensearch.action.admin.cluster.repositories.put.PutRepositoryRequest;
@@ -60,6 +59,7 @@
 import org.opensearch.client.RestClientBuilder;
 import org.opensearch.client.WarningsHandler;
 import org.opensearch.common.CheckedRunnable;
+import org.opensearch.common.SetOnce;
 import org.opensearch.common.Strings;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.settings.Settings;