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cat master API

cat APIs are only intended for human consumption using the command line or Kibana console. They are not intended for use by applications. For application consumption, use the nodes info API.

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

Request

GET /_cat/master

Prerequisites

If the Elasticsearch security features are enabled, you must have the monitor or manage cluster privilege to use this API.

Query parameters

format: (Optional, string) Short version of the HTTP accept header. Valid values include JSON, YAML, etc.
h: (Optional, string) Comma-separated list of column names to display.
help: (Optional, Boolean) If true, the response includes help information. Defaults to false.
local: (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.
master_timeout: (Optional, time units) Period 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.
s: (Optional, string) Comma-separated list of column names or column aliases used to sort the response.
v: (Optional, Boolean) If true, the response includes column headings. Defaults to false.

Examples

GET /_cat/master?v=true

The API returns the following response:

id                     host      ip        node
YzWoH_2BT-6UjVGDyPdqYg 127.0.0.1 127.0.0.1 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 192.168.56.30 H5dfFeA
[2] 19:16:37 [SUCCESS] es2.vm
Ntgn2DcuTjGuXlhKDUD4vA 192.168.56.30 H5dfFeA
[3] 19:16:37 [SUCCESS] es1.vm
Ntgn2DcuTjGuXlhKDUD4vA 192.168.56.30 H5dfFeA

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https://www.elastic.co/guide/en/elasticsearch/reference/7.17/cat-master.html