cat master APIedit

Returns information about the master node, including the ID, bound IP address, and name.


GET /_cat/master

Query parametersedit

(Optional, string) Short version of the HTTP accept header. Valid values include JSON, YAML, etc.
(Optional, string) Comma-separated list of column names to display.
(Optional, boolean) If true, the response includes help information. Defaults to false.
(Optional, boolean) If true, the request retrieves information from the local node only. Defaults to false, which means information is retrieved from the master node.
(Optional, time units) Specifies the period of time to wait for a connection to the master node. If no response is received before the timeout expires, the request fails and returns an error. Defaults to 30s.
(Optional, string) Comma-separated list of column names or column aliases used to sort the response.
(Optional, boolean) If true, the response includes column headings. Defaults to false.


GET /_cat/master?v

The API returns the following response:

id                     host      ip        node
YzWoH_2BT-6UjVGDyPdqYg YzWoH_2

This information is also available via the nodes command, but this is slightly shorter when all you want to do, for example, is verify all nodes agree on the master:

% pssh -i -h list.of.cluster.hosts curl -s localhost:9200/_cat/master
[1] 19:16:37 [SUCCESS] es3.vm
Ntgn2DcuTjGuXlhKDUD4vA H5dfFeA
[2] 19:16:37 [SUCCESS] es2.vm
Ntgn2DcuTjGuXlhKDUD4vA H5dfFeA
[3] 19:16:37 [SUCCESS] es1.vm
Ntgn2DcuTjGuXlhKDUD4vA H5dfFeA