175 lines
5.1 KiB
Plaintext
175 lines
5.1 KiB
Plaintext
[[indices-clone-index]]
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=== Clone index API
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++++
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<titleabbrev>Clone index</titleabbrev>
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++++
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Clones an existing index.
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[source,console]
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--------------------------------------------------
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POST /twitter/_clone/cloned-twitter-index
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--------------------------------------------------
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// TEST[s/^/PUT twitter\n{"settings":{"index.number_of_shards" : 5,"blocks.write":true}}\n/]
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[[clone-index-api-request]]
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==== {api-request-title}
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`POST /<index>/_clone/<target-index>`
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`PUT /<index>/_clone/<target-index>`
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[[clone-index-api-prereqs]]
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==== {api-prereq-title}
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To clone an index,
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the index must be marked as read-only
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and have a <<cluster-health,cluster health>> status of `green`.
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For example,
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the following request prevents write operations on `my_source_index`
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so it can be cloned.
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Metadata changes like deleting the index are still allowed.
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[source,console]
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--------------------------------------------------
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PUT /my_source_index/_settings
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{
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"settings": {
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"index.blocks.write": true
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}
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}
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--------------------------------------------------
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// TEST[s/^/PUT my_source_index\n/]
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[[clone-index-api-desc]]
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==== {api-description-title}
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Use the clone index API
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to clone an existing index into a new index,
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where each original primary shard is cloned
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into a new primary shard in the new index.
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[[cloning-works]]
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===== How cloning works
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Cloning works as follows:
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* First, it creates a new target index with the same definition as the source
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index.
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* Then it hard-links segments from the source index into the target index. (If
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the file system doesn't support hard-linking, then all segments are copied
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into the new index, which is a much more time consuming process.)
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* Finally, it recovers the target index as though it were a closed index which
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had just been re-opened.
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[[clone-index]]
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===== Clone an index
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To clone `my_source_index` into a new index called `my_target_index`, issue
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the following request:
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[source,console]
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--------------------------------------------------
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POST /my_source_index/_clone/my_target_index
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--------------------------------------------------
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// TEST[continued]
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The above request returns immediately once the target index has been added to
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the cluster state -- it doesn't wait for the clone operation to start.
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[IMPORTANT]
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=====================================
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Indices can only be cloned if they meet the following requirements:
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* The target index must not exist.
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* The source index must have the same number of primary shards as the target index.
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* The node handling the clone process must have sufficient free disk space to
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accommodate a second copy of the existing index.
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=====================================
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The `_clone` API is similar to the <<indices-create-index, `create index` API>>
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and accepts `settings` and `aliases` parameters for the target index:
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[source,console]
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--------------------------------------------------
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POST /my_source_index/_clone/my_target_index
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{
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"settings": {
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"index.number_of_shards": 5 <1>
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},
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"aliases": {
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"my_search_indices": {}
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}
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}
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--------------------------------------------------
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// TEST[s/^/PUT my_source_index\n{"settings": {"index.blocks.write": true, "index.number_of_shards": "5"}}\n/]
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<1> The number of shards in the target index. This must be equal to the
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number of shards in the source index.
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NOTE: Mappings may not be specified in the `_clone` request. The mappings of
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the source index will be used for the target index.
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[[monitor-cloning]]
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===== Monitor the cloning process
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The cloning process can be monitored with the <<cat-recovery,`_cat recovery`
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API>>, or the <<cluster-health, `cluster health` API>> can be used to wait
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until all primary shards have been allocated by setting the `wait_for_status`
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parameter to `yellow`.
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The `_clone` API returns as soon as the target index has been added to the
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cluster state, before any shards have been allocated. At this point, all
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shards are in the state `unassigned`. If, for any reason, the target index
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can't be allocated, its primary shard will remain `unassigned` until it
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can be allocated on that node.
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Once the primary shard is allocated, it moves to state `initializing`, and the
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clone process begins. When the clone operation completes, the shard will
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become `active`. At that point, {es} will try to allocate any
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replicas and may decide to relocate the primary shard to another node.
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[[clone-wait-active-shards]]
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===== Wait for active shards
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Because the clone operation creates a new index to clone the shards to,
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the <<create-index-wait-for-active-shards,wait for active shards>> setting
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on index creation applies to the clone index action as well.
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[[clone-index-api-path-params]]
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==== {api-path-parms-title}
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`<index>`::
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(Required, string)
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Name of the source index to clone.
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include::{docdir}/rest-api/common-parms.asciidoc[tag=target-index]
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[[clone-index-api-query-params]]
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==== {api-query-parms-title}
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include::{docdir}/rest-api/common-parms.asciidoc[tag=wait_for_active_shards]
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include::{docdir}/rest-api/common-parms.asciidoc[tag=timeoutparms]
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[[clone-index-api-request-body]]
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==== {api-request-body-title}
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include::{docdir}/rest-api/common-parms.asciidoc[tag=target-index-aliases]
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include::{docdir}/rest-api/common-parms.asciidoc[tag=target-index-settings]
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