Use the cluster update settings API to dynamically configure remote settings on every node in the cluster. The following request adds three remote clusters: cluster_one, cluster_two, and cluster_three.

The seeds parameter specifies the hostname and transport port (default 9300) of a seed node in the remote cluster.

The mode parameter determines the configured connection mode, which defaults to sniff. Because cluster_one doesn’t specify a mode, it uses the default. Both cluster_two and cluster_three explicitly use different modes.

PUT _cluster/settings
{
  "persistent": {
    "cluster": {
      "remote": {
        "cluster_one": {
          "seeds": [
            "127.0.0.1:9300"
          ]
        },
        "cluster_two": {
          "mode": "sniff",
          "seeds": [
            "127.0.0.1:9301"
          ],
          "transport.compress": true,
          "skip_unavailable": true
        },
        "cluster_three": {
          "mode": "proxy",
          "proxy_address": "127.0.0.1:9302"
        }
      }
    }
  }
}

You can dynamically update settings for a remote cluster after the initial configuration. The following request updates the compression settings for cluster_two, and the compression and ping schedule settings for cluster_three.

response = client.cluster.put_settings(
  body: {
    persistent: {
      cluster: {
        remote: {
          cluster_two: {
            'transport.compress' => false
          },
          cluster_three: {
            'transport.compress' => true,
            'transport.ping_schedule' => '60s'
          }
        }
      }
    }
  }
)
puts response

PUT _cluster/settings
{
  "persistent": {
    "cluster": {
      "remote": {
        "cluster_two": {
          "transport.compress": false
        },
        "cluster_three": {
          "transport.compress": true,
          "transport.ping_schedule": "60s"
        }
      }
    }
  }
}

You can delete a remote cluster from the cluster settings by passing null values for each remote cluster setting. The following request removes cluster_two from the cluster settings, leaving cluster_one and cluster_three intact:

response = client.cluster.put_settings(
  body: {
    persistent: {
      cluster: {
        remote: {
          cluster_two: {
            mode: nil,
            seeds: nil,
            skip_unavailable: nil,
            'transport.compress' => nil
          }
        }
      }
    }
  }
)
puts response

PUT _cluster/settings
{
  "persistent": {
    "cluster": {
      "remote": {
        "cluster_two": {
          "mode": null,
          "seeds": null,
          "skip_unavailable": null,
          "transport.compress": null
        }
      }
    }
  }
}

If you specify settings in elasticsearch.yml, only the nodes with those settings can connect to the remote cluster and serve remote cluster requests.

In the following example, cluster_one, cluster_two, and cluster_three are arbitrary cluster aliases representing the connection to each cluster. These names are subsequently used to distinguish between local and remote indices.

cluster:
    remote:
        cluster_one:
            seeds: 127.0.0.1:9300
        cluster_two:
            mode: sniff
            seeds: 127.0.0.1:9301
            transport.compress: true      
            skip_unavailable: true        
        cluster_three:
            mode: proxy
            proxy_address: 127.0.0.1:9302 

The cross-cluster replication user requires different cluster and index privileges on the remote cluster and local cluster. Use the following requests to create separate roles on the local and remote clusters, and then create a user with the required roles.

Remote clusteredit

On the remote cluster that contains the leader index, the cross-cluster replication role requires the read_ccr cluster privilege, and monitor and read privileges on the leader index.

The following request creates a remote-replication role on the remote cluster:

POST /_security/role/remote-replication
{
  "cluster": [
    "read_ccr"
  ],
  "indices": [
    {
      "names": [
        "leader-index-name"
      ],
      "privileges": [
        "monitor",
        "read"
      ]
    }
  ]
}

Local clusteredit

On the local cluster that contains the follower index, the remote-replication role requires the manage_ccr cluster privilege, and monitor, read, write, and manage_follow_index privileges on the follower index.

The following request creates a remote-replication role on the local cluster:

POST /_security/role/remote-replication
{
  "cluster": [
    "manage_ccr"
  ],
  "indices": [
    {
      "names": [
        "follower-index-name"
      ],
      "privileges": [
        "monitor",
        "read",
        "write",
        "manage_follow_index"
      ]
    }
  ]
}

After creating the remote-replication role on each cluster, use the create or update users API to create a user on the local cluster cluster and assign the remote-replication role. For example, the following request assigns the remote-replication role to a user named cross-cluster-user:

POST /_security/user/cross-cluster-user
{
  "password" : "l0ng-r4nd0m-p@ssw0rd",
  "roles" : [ "remote-replication" ]
}

You can then configure cross-cluster replication to replicate your data across datacenters.

The cross-cluster search user requires different cluster and index privileges on the remote cluster and local cluster. The following requests create separate roles on the local and remote clusters, and then create a user with the required roles.

Remote clusteredit

On the remote cluster, the cross-cluster search role requires the read and read_cross_cluster privileges for the target indices.

The following request creates a remote-search role on the remote cluster:

POST /_security/role/remote-search
{
  "indices": [
    {
      "names": [
        "target-indices"
      ],
      "privileges": [
        "read",
        "read_cross_cluster"
      ]
    }
  ]
}

Local clusteredit

On the local cluster, which is the cluster used to initiate cross cluster search, a user only needs the remote-search role. The role privileges can be empty.

The following request creates a remote-search role on the local cluster:

POST /_security/role/remote-search
{}

After creating the remote-search role on each cluster, use the create or update users API to create a user on the local cluster and assign the remote-search role. For example, the following request assigns the remote-search role to a user named cross-search-user:

POST /_security/user/cross-search-user
{
  "password" : "l0ng-r4nd0m-p@ssw0rd",
  "roles" : [ "remote-search" ]
}

Users with the remote-search role can then search across clusters.

When using Kibana to search across multiple clusters, a two-step authorization process determines whether or not the user can access data streams and indices on a remote cluster:

To grant Kibana users access to remote clusters, assign them a local role with read privileges to indices on the remote clusters. You specify data streams and indices in a remote cluster as <remote_cluster_name>:<target>.

To grant users read access on the remote data streams and indices, you must create a matching role on the remote clusters that grants the read_cross_cluster privilege with access to the appropriate data streams and indices.

For example, you might be actively indexing Logstash data on a local cluster and and periodically offload older time-based indices to an archive on your remote cluster. You want to search across both clusters, so you must enable Kibana users on both clusters.

Local clusteredit

On the local cluster, create a logstash-reader role that grants read and view_index_metadata privileges on the local logstash-* indices.

POST /_security/role/logstash-reader
{
  "indices": [
    {
      "names": [
        "logstash-*"
        ],
        "privileges": [
          "read",
          "view_index_metadata"
          ]
    }
  ]
}

Assign your Kibana users a role that grants access to Kibana, as well as your logstash_reader role. For example, the following request creates the cross-cluster-kibana user and assigns the kibana-access and logstash-reader roles.

PUT /_security/user/cross-cluster-kibana
{
  "password" : "l0ng-r4nd0m-p@ssw0rd",
  "roles" : [
    "logstash-reader",
    "kibana-access"
    ]
}

Remote clusteredit

On the remote cluster, create a logstash-reader role that grants the read_cross_cluster privilege and read and view_index_metadata privileges for the logstash-* indices.

POST /_security/role/logstash-reader
{
  "indices": [
    {
      "names": [
        "logstash-*"
        ],
        "privileges": [
          "read_cross_cluster",
          "read",
          "view_index_metadata"
          ]
    }
  ]
}