[[cluster-state]]
=== Cluster State

Returns metadata about the state of the cluster.

[[cluster-state-api-request]]
==== {api-request-title}

`GET /_cluster/state/{metrics}/{index}`

[[cluster-state-api-desc]]
==== {api-description-title}

The cluster state API allows access to metadata representing the state of the
whole cluster. This includes information such as

* the set of nodes in the cluster

* all cluster-level settings

* information about the indices in the cluster, including their mappings and
  settings

* the locations of all the shards in the cluster.

The response is an internal representation of the cluster state and its format
may change from version to version. If possible, you should obtain any
information from the cluster state using the other, more stable,
<<cluster,cluster APIs>>.

The response provides the cluster state itself, which can be filtered to only
retrieve the parts of interest as described below.

The cluster's `cluster_uuid` is also returned as part of the top-level response,
in addition to the `metadata` section. added[6.4.0]

NOTE: While the cluster is still forming, it is possible for the `cluster_uuid`
      to be `_na_` as well as the cluster state's version to be `-1`.

By default, the cluster state request is routed to the master node, to ensure
that the latest cluster state is returned. For debugging purposes, you can
retrieve the cluster state local to a particular node by adding `local=true` to
the query string.

[[cluster-state-api-path-params]]
==== {api-path-parms-title}

The cluster state contains information about all the indices in the cluster,
including their mappings, as well as templates and other metadata. This means it
can sometimes be quite large. To avoid the need to process all this information
you can request only the part of the cluster state that you need:

`{metrics}`::
    (Optional, string) A comma-separated list of the following options:
+
--
  `_all`::
      Shows all metrics.
    
  `blocks`::
      Shows the `blocks` part of the response.

  `master_node`::
      Shows the elected `master_node` part of the response.
    
  `metadata`::
      Shows the `metadata` part of the response. If you supply a comma separated
      list of indices, the returned output will only contain metadata for these
      indices.

  `nodes`::
      Shows the `nodes` part of the response.

  `routing_nodes`::
      Shows the `routing_nodes` part of the response.

  `routing_table`::
      Shows the `routing_table` part of the response. If you supply a comma
      separated list of indices, the returned output will only contain the 
      routing table for these indices.
    
  `version`::
      Shows the cluster state version.
--

include::{docdir}/rest-api/common-parms.asciidoc[tag=index]


[[cluster-state-api-query-params]]
==== {api-query-parms-title}

`allow_no_indices`::
    (Optional, boolean) If `true`, the wildcard indices expression that resolves 
    into no concrete indices will be ignored. (This includes `_all` string or 
    when no indices have been specified).

`expand_wildcards`::
    (Optional, string) Whether to expand wildcard expression to concrete indices 
    that are open, closed or both. Available options: `open`, `closed`, `none`, 
    `all`.

include::{docdir}/rest-api/common-parms.asciidoc[tag=flat-settings]
    
`ignore_unavailable`::
    (Optional, boolean) If `true`, unavailable indices (missing or closed) will 
    be ignored.

include::{docdir}/rest-api/common-parms.asciidoc[tag=local]

include::{docdir}/rest-api/common-parms.asciidoc[tag=master-timeout]

`wait_for_metadata_version`::
    (Optional, integer) Waits for the metadata version to be equal or greater 
    than the specified metadata version.
    
`wait_for_timeout`::
    (Optional, <<time-units, time units>>) Specifies the maximum time to wait 
    for wait_for_metadata_version before timing out.


[[cluster-state-api-example]]
==== {api-examples-title}

The following example returns only `metadata` and `routing_table` data for the
`foo` and `bar` indices:

[source,js]
--------------------------------------------------
GET /_cluster/state/metadata,routing_table/foo,bar
--------------------------------------------------
// CONSOLE

The next example returns everything for the `foo` and `bar` indices:

[source,js]
--------------------------------------------------
GET /_cluster/state/_all/foo,bar
--------------------------------------------------
// CONSOLE

This example returns only the `blocks` metadata:

[source,js]
--------------------------------------------------
GET /_cluster/state/blocks
--------------------------------------------------
// CONSOLE