[Backport 2.x] Disallow multiple data paths for search nodes

CHANGELOG.md

@@ -6,6 +6,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 ## [Unreleased 2.x]
 ### Added
 - Add GeoTile and GeoHash Grid aggregations on GeoShapes. ([#5589](https://github.com/opensearch-project/OpenSearch/pull/5589))
+- Disallow multiple data paths for search nodes ([#6427](https://github.com/opensearch-project/OpenSearch/pull/6427))
 
 ### Dependencies
 

server/src/main/java/org/opensearch/bootstrap/BootstrapChecks.java

@@ -38,15 +38,18 @@
 import org.apache.lucene.util.Constants;
 import org.opensearch.bootstrap.jvm.DenyJvmVersionsParser;
 import org.opensearch.cluster.coordination.ClusterBootstrapService;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.transport.BoundTransportAddress;
 import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.discovery.DiscoveryModule;
+import org.opensearch.env.Environment;
 import org.opensearch.index.IndexModule;
 import org.opensearch.monitor.jvm.JvmInfo;
 import org.opensearch.monitor.process.ProcessProbe;
+import org.opensearch.node.NodeRoleSettings;
 import org.opensearch.node.NodeValidationException;
 
 import java.io.BufferedReader;
@@ -228,6 +231,7 @@ static List<BootstrapCheck> checks() {
         checks.add(new JavaVersionCheck());
         checks.add(new AllPermissionCheck());
         checks.add(new DiscoveryConfiguredCheck());
+        checks.add(new MultipleDataPathCheck());
         return Collections.unmodifiableList(checks);
     }
 
@@ -751,4 +755,25 @@ public BootstrapCheckResult check(BootstrapContext context) {
             );
         }
     }
+
+    /**
+     * Bootstrap check that if a search node contains multiple data paths
+     */
+    static class MultipleDataPathCheck implements BootstrapCheck {
+
+        @Override
+        public BootstrapCheckResult check(BootstrapContext context) {
+            if (NodeRoleSettings.NODE_ROLES_SETTING.get(context.settings()).contains(DiscoveryNodeRole.SEARCH_ROLE)
+                && Environment.PATH_DATA_SETTING.get(context.settings()).size() > 1) {
+                return BootstrapCheckResult.failure("Multiple data paths are not allowed for search nodes");
+            }
+            return BootstrapCheckResult.success();
+        }
+
+        @Override
+        public final boolean alwaysEnforce() {
+            return true;
+        }
+
+    }
 }

server/src/test/java/org/opensearch/bootstrap/BootstrapChecksTests.java

@@ -36,19 +36,24 @@
 import org.apache.lucene.util.Constants;
 import org.opensearch.cluster.coordination.ClusterBootstrapService;
 import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.cluster.node.DiscoveryNodeRole;
 import org.opensearch.common.CheckedConsumer;
+import org.opensearch.common.io.PathUtils;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.transport.BoundTransportAddress;
 import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.discovery.DiscoveryModule;
 import org.opensearch.discovery.SettingsBasedSeedHostsProvider;
+import org.opensearch.env.Environment;
 import org.opensearch.monitor.jvm.JvmInfo;
+import org.opensearch.node.NodeRoleSettings;
 import org.opensearch.node.NodeValidationException;
 import org.opensearch.test.AbstractBootstrapCheckTestCase;
 import org.hamcrest.Matcher;
 
 import java.lang.Runtime.Version;
 import java.net.InetAddress;
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -774,4 +779,41 @@ Version getVersion() {
         version.set(Runtime.version());
         BootstrapChecks.check(emptyContext, true, Collections.singletonList(check));
     }
+
+    public void testMultipleDataPathsForSearchNodeCheck() {
+        Path path = PathUtils.get(createTempDir().toString());
+        String[] paths = new String[] { path.resolve("a").toString(), path.resolve("b").toString() };
+
+        final NodeValidationException e = expectThrows(
+            NodeValidationException.class,
+            () -> performDataPathsCheck(paths, DiscoveryNodeRole.SEARCH_ROLE.roleName())
+        );
+        assertThat(e.getMessage(), containsString("Multiple data paths are not allowed for search nodes"));
+    }
+
+    public void testMultipleDataPathsForDataNodeCheck() throws NodeValidationException {
+        Path path = PathUtils.get(createTempDir().toString());
+        String[] paths = new String[] { path.resolve("a").toString(), path.resolve("b").toString() };
+
+        performDataPathsCheck(paths, DiscoveryNodeRole.DATA_ROLE.roleName());
+    }
+
+    public void testSingleDataPathForSearchNodeCheck() throws NodeValidationException {
+        Path path = PathUtils.get(createTempDir().toString());
+        String[] paths = new String[] { path.resolve("a").toString() };
+
+        performDataPathsCheck(paths, DiscoveryNodeRole.SEARCH_ROLE.roleName());
+    }
+
+    private void performDataPathsCheck(String[] paths, String roleName) throws NodeValidationException {
+        final BootstrapContext context = createTestContext(
+            Settings.builder()
+                .putList(NodeRoleSettings.NODE_ROLES_SETTING.getKey(), Collections.singletonList(roleName))
+                .putList(Environment.PATH_DATA_SETTING.getKey(), paths)
+                .build(),
+            Metadata.EMPTY_METADATA
+        );
+        final List<BootstrapCheck> checks = Collections.singletonList(new BootstrapChecks.MultipleDataPathCheck());
+        BootstrapChecks.check(context, true, checks);
+    }
 }