Create follower API
editCreate follower API
editCreates a follower index.
Description
editThis API creates a new follower index that is configured to follow the referenced leader index. When this API returns, the follower index exists, and cross-cluster replication starts replicating operations from the leader index to the follower index.
Request
editPUT /<follower_index>/_ccr/follow?wait_for_active_shards=1 { "remote_cluster" : "<remote_cluster>", "leader_index" : "<leader_index>" }
The wait_for_active_shards
parameter specifies the number of shards to wait on being active
before responding. This defaults to waiting on none of the shards to be active. A shard must
be restored from the leader index being active. Restoring a follower shard requires transferring
all the remote Lucene segment files to the follower index.
Path Parameters
edit-
follower_index
(required) - (string) the name of the follower index
Request Body
edit-
remote_cluster
(required) - (string) the remote cluster containing the leader index
-
leader_index
(required) - (string) the name of the index in the leader cluster to follow
-
max_read_request_operation_count
- (integer) the maximum number of operations to pull per read from the remote cluster
-
max_outstanding_read_requests
- (long) the maximum number of outstanding reads requests from the remote cluster
-
max_read_request_size
- (byte value) the maximum size in bytes of per read of a batch of operations pulled from the remote cluster
-
max_write_request_operation_count
- (integer) the maximum number of operations per bulk write request executed on the follower
-
max_write_request_size
- (byte value) the maximum total bytes of operations per bulk write request executed on the follower
-
max_outstanding_write_requests
- (integer) the maximum number of outstanding write requests on the follower
-
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 will be deferred until the number of queued operations goes below the limit
-
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 will be deferred until the total bytes of queued operations goes below the limit
-
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
-
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 will return to the follower so that it can update some statistics, and then the follower will immediately attempt to read from the leader again
Default values
editThe following output from the follow info api describes all the default values for the above described index follow request parameters:
{ "follower_indices" : [ { "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" } } ] }
Authorization
editIf the Elasticsearch security features are enabled, you must have write
, monitor
,
and manage_follow_index
index privileges for the follower index. You must have
read
and monitor
index privileges for the leader index. You must also have
manage_ccr
cluster privileges on the cluster that contains the follower index.
For more information, see
Security privileges.
Example
editThis example creates a follower index named follower_index
:
PUT /follower_index/_ccr/follow?wait_for_active_shards=1 { "remote_cluster" : "remote_cluster", "leader_index" : "leader_index", "max_read_request_operation_count" : 1024, "max_outstanding_read_requests" : 16, "max_read_request_size" : "1024k", "max_write_request_operation_count" : 32768, "max_write_request_size" : "16k", "max_outstanding_write_requests" : 8, "max_write_buffer_count" : 512, "max_write_buffer_size" : "512k", "max_retry_delay" : "10s", "read_poll_timeout" : "30s" }
The API returns the following result:
{ "follow_index_created" : true, "follow_index_shards_acked" : true, "index_following_started" : true }