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Elasticsearch Guide [7.7] » REST APIs » Cross-cluster replication APIs » Get follower info API
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Get follower info APIedit

Retrieves information about all follower indices.

Requestedit 

GET /<index>/_ccr/info

Prerequisitesedit

  • If the Elasticsearch security features are enabled, you must have monitor cluster privileges. For more information, see Security privileges.

Descriptionedit

This API lists the parameters and the status for each follower index. For example, the results include follower index names, leader index names, replication options and whether the follower indices are active or paused.

Path parametersedit

<index>
(Required, string) A comma-delimited list of follower index patterns.

Response bodyedit

This API returns the following information:

follower_indices
(array) An array of follower index statistics.

The indices array consists of objects containing several fields:

indices[].follower_index
(string) The name of the follower index.
indices[].remote_cluster
(string) The remote cluster that contains the leader index.
indices[].leader_index
(string) The name of the index in the leader cluster that is followed.
indices[].status
(string) Whether index following is active or paused.
indices[].parameters
(object) An object that encapsulates cross-cluster replication parameters.

The parameters contains the following fields:

indices[].parameters.max_read_request_operation_count
(integer) The maximum number of operations to pull per read from the remote cluster.
indices[].parameters.max_outstanding_read_requests
(long) The maximum number of outstanding read requests from the remote cluster.
indices[].parameters.max_read_request_size
(byte value) The maximum size in bytes of per read of a batch of operations pulled from the remote cluster.
indices[].parameters.max_write_request_operation_count
(integer) The maximum number of operations per bulk write request executed on the follower.
indices[].parameters.max_write_request_size
(byte value) The maximum total bytes of operations per bulk write request executed on the follower.
indices[].parameters.max_outstanding_write_requests
(integer) The maximum number of outstanding write requests on the follower.
indices[].parameters.max_write_buffer_count
(integer) The maximum number of operations that can be queued for writing. When this limit is reached, reads from the remote cluster are deferred until the number of queued operations goes below the limit.
indices[].parameters.max_write_buffer_size
(byte value) The maximum total bytes of operations that can be queued for writing. When this limit is reached, reads from the remote cluster are deferred until the total bytes of queued operations goes below the limit.
indices[].parameters.max_retry_delay
(time value) The maximum time to wait before retrying an operation that failed exceptionally. An exponential backoff strategy is employed when retrying.
indices[].parameters.read_poll_timeout
(time value) The maximum time to wait for new operations on the remote cluster when the follower index is synchronized with the leader index. When the timeout has elapsed, the poll for operations returns to the follower so that it can update some statistics, then the follower immediately attempts to read from the leader again.

Examplesedit

This example retrieves follower info:

GET /follower_index/_ccr/info

The API returns the following results:

{
    "follower_indices" : [
        {
            "follower_index" : "follower_index",
            "remote_cluster" : "remote_cluster",
            "leader_index" : "leader_index",
            "status" : "active",
            "parameters" : {
                "max_read_request_operation_count" : 5120,
                "max_read_request_size" : "32mb",
                "max_outstanding_read_requests" : 12,
                "max_write_request_operation_count" : 5120,
                "max_write_request_size" : "9223372036854775807b",
                "max_outstanding_write_requests" : 9,
                "max_write_buffer_count" : 2147483647,
                "max_write_buffer_size" : "512mb",
                "max_retry_delay" : "500ms",
                "read_poll_timeout" : "1m"
            }
        }
    ]
}
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