Cluster State

edit

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 APIs.

GET /_cluster/state

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. [6.4.0] Added in 6.4.0.

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.

Response Filters

edit

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:

GET /_cluster/state/{metrics}
GET /_cluster/state/{metrics}/{indices}

{metrics} is a comma-separated list of the following options.

version
Shows the cluster state version.
master_node
Shows the elected master_node part of the response
nodes
Shows the 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.
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.
blocks
Shows the blocks part of the response.
_all
Shows all metrics.

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

GET /_cluster/state/metadata,routing_table/foo,bar

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

GET /_cluster/state/_all/foo,bar

Finally, this example return only the blocks metadata:

GET /_cluster/state/blocks