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Cluster health

Introduced 1.0

The most basic cluster health request returns a simple status of the health of your cluster. OpenSearch expresses cluster health in three colors: green, yellow, and red. A green status means all primary shards and their replicas are allocated to nodes. A yellow status means all primary shards are allocated to nodes, but some replicas aren’t. A red status means at least one primary shard is not allocated to any node.

To get the status of a specific index, provide the index name.

Example

This request waits 50 seconds for the cluster to reach the yellow status or better:

GET _cluster/health?wait_for_status=yellow&timeout=50s

If the cluster health becomes yellow or green before 50 seconds elapse, it returns a response immediately. Otherwise it returns a response as soon as it exceeds the timeout.

Path and HTTP methods

GET _cluster/health
GET _cluster/health/<index>

Query parameters

The following table lists the available query parameters. All query parameters are optional.

Parameter Type Description
expand_wildcards Enum Expands wildcard expressions to concrete indexes. Combine multiple values with commas. Supported values are all, open, closed, hidden, and none. Default is open.
level Enum The level of detail for returned health information. Supported values are cluster, indices, and shards. Default is cluster.
local Boolean Whether to return information from the local node only instead of from the cluster manager node. Default is false.
cluster_manager_timeout Time The amount of time to wait for a connection to the cluster manager node. Default is 30 seconds.
timeout Time The amount of time to wait for a response. If the timeout expires, the request fails. Default is 30 seconds.
wait_for_active_shards String Wait until the specified number of shards is active before returning a response. all for all shards. Default is 0.
wait_for_nodes String Wait for N number of nodes. Use 12 for exact match, >12 and <12 for range.
wait_for_events Enum Wait until all currently queued events with the given priority are processed. Supported values are immediate, urgent, high, normal, low, and languid.
wait_for_no_relocating_shards Boolean Whether to wait until there are no relocating shards in the cluster. Default is false.
wait_for_no_initializing_shards Boolean Whether to wait until there are no initializing shards in the cluster. Default is false.
wait_for_status Enum Wait until the cluster health reaches the specified status or better. Supported values are green, yellow, and red.

Example request

The following example request retrieves cluster health for all indexes in the cluster:

GET _cluster/health

Example response

The response contains cluster health information:

{
  "cluster_name" : "opensearch-cluster",
  "status" : "green",
  "timed_out" : false,
  "number_of_nodes" : 2,
  "number_of_data_nodes" : 2,
  "discovered_master" : true,
  "active_primary_shards" : 6,
  "active_shards" : 12,
  "relocating_shards" : 0,
  "initializing_shards" : 0,
  "unassigned_shards" : 0,
  "delayed_unassigned_shards" : 0,
  "number_of_pending_tasks" : 0,
  "number_of_in_flight_fetch" : 0,
  "task_max_waiting_in_queue_millis" : 0,
  "active_shards_percent_as_number" : 100.0
}

Response fields

The following table lists all response fields.

Field Data type Description
cluster_name String The name of the cluster.
status String The cluster health status, which represents the state of shard allocation in the cluster. May be green, yellow, or red.
number_of_nodes Integer The number of nodes in the cluster.
number_of_data_nodes Integer The number of data nodes in the cluster.
discovered_cluster_manager Boolean Specifies whether the cluster manager is discovered.
active_primary_shards Integer The number of active primary shards.
active_shards Integer The total number of active shards, including primary and replica shards.
relocating_shards Integer The number of relocating shards.
initializing_shards Integer The number of intializing shards.
unassigned_shards Integer The number of unassigned shards.
delayed_unassigned_shards Integer The number of delayed unassigned shards.
number_of_pending_tasks Integer The number of pending tasks in the cluster.
number_of_in_flight_fetch Integer The number of unfinished fetches.
task_max_waiting_in_queue_millis Integer The maximum wait time for all tasks waiting to be performed, in milliseconds.
active_shards_percent_as_number Double The percentage of active shards in the cluster.

Required permissions

If you use the security plugin, make sure you have the appropriate permissions: cluster:monitor/health.

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