[DOCS] Reformat clone index API docs (#46762)

docs/reference/indices/clone-index.asciidoc

@@ -1,68 +1,82 @@
 [[indices-clone-index]]
-=== Clone Index
+=== Clone index API
+++++
+<titleabbrev>Clone index</titleabbrev>
+++++
 
-The clone index API allows you to clone an existing index into a new index,
-where each original primary shard is cloned into a new primary shard in
-the new index.
+Clones an existing index.
 
-[float]
-==== How does cloning work?
-
-Cloning works as follows:
+[source,console]
+--------------------------------------------------
+POST /twitter/_clone/cloned-twitter-index
+--------------------------------------------------
+// TEST[s/^/PUT twitter\n{"settings":{"index.number_of_shards" : 5,"blocks.write":true}}\n/]
 
-* First, it creates a new target index with the same definition as the source
-  index.
 
-* Then it hard-links segments from the source index into the target index. (If
-  the file system doesn't support hard-linking, then all segments are copied
-  into the new index, which is a much more time consuming process.)
+[[clone-index-api-request]]
+==== {api-request-title}
 
-* Finally, it recovers the target index as though it were a closed index which
-  had just been re-opened.
+`POST /<index>/_clone/<target-index>`
 
-[float]
-==== Preparing an index for cloning
+`PUT /<index>/_clone/<target-index>`
 
-Create a new index:
 
-[source,console]
---------------------------------------------------
-PUT my_source_index
-{
-  "settings": {
-    "index.number_of_shards" : 5
-  }
-}
---------------------------------------------------
+[[clone-index-api-prereqs]]
+==== {api-prereq-title}
 
-In order to clone an index, the index must be marked as read-only,
-and have <<cluster-health,health>> `green`.
+To clone an index,
+the index must be marked as read-only
+and have a <<cluster-health,cluster health>> status of `green`.
 
-This can be achieved with the following request:
+For example,
+the following request prevents write operations on `my_source_index`
+so it can be cloned.
+Metadata changes like deleting the index are still allowed.
 
 [source,console]
 --------------------------------------------------
 PUT /my_source_index/_settings
 {
   "settings": {
-    "index.blocks.write": true <1>
+    "index.blocks.write": true
   }
 }
 --------------------------------------------------
-// TEST[continued]
+// TEST[s/^/PUT my_source_index\n/]
+
 
-<1> Prevents write operations to this index while still allowing metadata
-    changes like deleting the index.
+[[clone-index-api-desc]]
+==== {api-description-title}
 
-[float]
-==== Cloning an index
+Use the clone index API
+to clone an existing index into a new index,
+where each original primary shard is cloned
+into a new primary shard in the new index.
+
+[[cloning-works]]
+===== How cloning works
+
+Cloning works as follows:
+
+* First, it creates a new target index with the same definition as the source
+  index.
+
+* Then it hard-links segments from the source index into the target index. (If
+  the file system doesn't support hard-linking, then all segments are copied
+  into the new index, which is a much more time consuming process.)
+
+* Finally, it recovers the target index as though it were a closed index which
+  had just been re-opened.
+
+[[clone-index]]
+===== Clone an index
 
 To clone `my_source_index` into a new index called `my_target_index`, issue
 the following request:
 
 [source,console]
 --------------------------------------------------
-POST my_source_index/_clone/my_target_index
+POST /my_source_index/_clone/my_target_index
 --------------------------------------------------
 // TEST[continued]
 
@@ -72,9 +86,9 @@ the cluster state -- it doesn't wait for the clone operation to start.
 [IMPORTANT]
 =====================================
 
-Indices can only be cloned if they satisfy the following requirements:
+Indices can only be cloned if they meet the following requirements:
 
-* the target index must not exist
+* The target index must not exist.
 
 * The source index must have the same number of primary shards as the target index.
 
@@ -88,7 +102,7 @@ and accepts `settings` and `aliases` parameters for the target index:
 
 [source,console]
 --------------------------------------------------
-POST my_source_index/_clone/my_target_index
+POST /my_source_index/_clone/my_target_index
 {
   "settings": {
     "index.number_of_shards": 5 <1>
@@ -107,10 +121,10 @@ POST my_source_index/_clone/my_target_index
 NOTE: Mappings may not be specified in the `_clone` request. The mappings of
 the source index will be used for the target index.
 
-[float]
-==== Monitoring the clone process
+[[monitor-cloning]]
+===== Monitor the cloning process
 
-The clone process can be monitored with the <<cat-recovery,`_cat recovery`
+The cloning process can be monitored with the <<cat-recovery,`_cat recovery`
 API>>, or the <<cluster-health, `cluster health` API>> can be used to wait
 until all primary shards have been allocated by setting the  `wait_for_status`
 parameter to `yellow`.
@@ -123,12 +137,38 @@ can be allocated on that node.
 
 Once the primary shard is allocated, it moves to state `initializing`, and the
 clone process begins. When the clone operation completes, the shard will
-become `active`. At that  point, Elasticsearch will try to allocate any
+become `active`. At that  point, {es} will try to allocate any
 replicas and may decide to relocate the primary shard to another node.
 
-[float]
-==== Wait For Active Shards
+[[clone-wait-active-shards]]
+===== Wait for active shards
 
 Because the clone operation creates a new index to clone the shards to,
 the <<create-index-wait-for-active-shards,wait for active shards>> setting
 on index creation applies to the clone index action as well.
+
+
+[[clone-index-api-path-params]]
+==== {api-path-parms-title}
+
+`<index>`::
+(Required, string)
+Name of the source index to clone.
+
+include::{docdir}/rest-api/common-parms.asciidoc[tag=target-index]
+
+
+[[clone-index-api-query-params]]
+==== {api-query-parms-title}
+
+include::{docdir}/rest-api/common-parms.asciidoc[tag=wait_for_active_shards]
+
+include::{docdir}/rest-api/common-parms.asciidoc[tag=timeoutparms]
+
+
+[[clone-index-api-request-body]]
+==== {api-request-body-title}
+
+include::{docdir}/rest-api/common-parms.asciidoc[tag=target-index-aliases]
+
+include::{docdir}/rest-api/common-parms.asciidoc[tag=target-index-settings]

docs/reference/rest-api/common-parms.asciidoc

@@ -10,6 +10,13 @@ tag::aliases[]
 index. See <<indices-aliases>>.
 end::aliases[]
 
+tag::target-index-aliases[]
+`aliases`::
+(Optional, <<indices-aliases,alias object>>)
+Index aliases which include the target index.
+See <<indices-aliases>>.
+end::target-index-aliases[]
+
 tag::allow-no-indices[]
 `allow_no_indices`::
 (Optional, boolean) If `true`,
@@ -473,15 +480,22 @@ the segment has most likely been written to disk
 but needs a <<indices-refresh,refresh>> to be searchable.
 end::segment-search[]
 
+tag::segment-size[]
+Disk space used by the segment, such as `50kb`.
+end::segment-size[]
+
 tag::settings[]
 `settings`::
 (Optional, <<index-modules-settings,index setting object>>) Configuration
 options for the index. See <<index-modules-settings>>.
 end::settings[]
 
-tag::segment-size[]
-Disk space used by the segment, such as `50kb`.
-end::segment-size[]
+tag::target-index-settings[]
+`settings`::
+(Optional, <<index-modules-settings,index setting object>>)
+Configuration options for the target index.
+See <<index-modules-settings>>.
+end::target-index-settings[]
 
 tag::slices[]
 `slices`::
@@ -518,6 +532,17 @@ tag::stats[]
 purposes.
 end::stats[]
 
+tag::target-index[]
+`<target-index>`::
++
+--
+(Required, string)
+Name of the target index to create.
+
+include::{docdir}/indices/create-index.asciidoc[tag=index-name-reqs]
+--
+end::target-index[]
+
 tag::terminate_after[]
 `terminate_after`::
 (Optional, integer) The maximum number of documents to collect for each shard,