Resolve the cluster Added in 8.13.0

GET /_resolve/cluster/{name}

Resolve the specified index expressions to return information about each cluster, including the local "querying" cluster, if included. If no index expression is provided, the API will return information about all the remote clusters that are configured on the querying cluster.

This endpoint is useful before doing a cross-cluster search in order to determine which remote clusters should be included in a search.

You use the same index expression with this endpoint as you would for cross-cluster search. Index and cluster exclusions are also supported with this endpoint.

For each cluster in the index expression, information is returned about:

  • Whether the querying ("local") cluster is currently connected to each remote cluster specified in the index expression. Note that this endpoint actively attempts to contact the remote clusters, unlike the remote/info endpoint.
  • Whether each remote cluster is configured with skip_unavailable as true or false.
  • Whether there are any indices, aliases, or data streams on that cluster that match the index expression.
  • Whether the search is likely to have errors returned when you do the cross-cluster search (including any authorization errors if you do not have permission to query the index).
  • Cluster version information, including the Elasticsearch server version.

For example, GET /_resolve/cluster/my-index-*,cluster*:my-index-* returns information about the local cluster and all remotely configured clusters that start with the alias cluster*. Each cluster returns information about whether it has any indices, aliases or data streams that match my-index-*.

Note on backwards compatibility

The ability to query without an index expression was added in version 8.18, so when querying remote clusters older than that, the local cluster will send the index expression dummy* to those remote clusters. Thus, if an errors occur, you may see a reference to that index expression even though you didn't request it. If it causes a problem, you can instead include an index expression like *:* to bypass the issue.

You may want to exclude a cluster or index from a search when:

  • A remote cluster is not currently connected and is configured with skip_unavailable=false. Running a cross-cluster search under those conditions will cause the entire search to fail.
  • A cluster has no matching indices, aliases or data streams for the index expression (or your user does not have permissions to search them). For example, suppose your index expression is logs*,remote1:logs* and the remote1 cluster has no indices, aliases or data streams that match logs*. In that case, that cluster will return no results from that cluster if you include it in a cross-cluster search.
  • The index expression (combined with any query parameters you specify) will likely cause an exception to be thrown when you do the search. In these cases, the "error" field in the _resolve/cluster response will be present. (This is also where security/permission errors will be shown.)
  • A remote cluster is an older version that does not support the feature you want to use in your search.

Test availability of remote clusters

The remote/info endpoint is commonly used to test whether the "local" cluster (the cluster being queried) is connected to its remote clusters, but it does not necessarily reflect whether the remote cluster is available or not. The remote cluster may be available, while the local cluster is not currently connected to it.

You can use the _resolve/cluster API to attempt to reconnect to remote clusters. For example with GET _resolve/cluster or GET _resolve/cluster/*:*. The connected field in the response will indicate whether it was successful. If a connection was (re-)established, this will also cause the remote/info endpoint to now indicate a connected status.

Path parameters

  • name string | array[string] Required

    A comma-separated list of names or index patterns for the indices, aliases, and data streams to resolve. Resources on remote clusters can be specified using the <cluster>:<name> syntax. Index and cluster exclusions (e.g., -cluster1:*) are also supported. If no index expression is specified, information about all remote clusters configured on the local cluster is returned without doing any index matching

Query parameters

  • If false, the request returns an error if any wildcard expression, index alias, or _all value targets only missing or closed indices. This behavior applies even if the request targets other open indices. For example, a request targeting foo*,bar* returns an error if an index starts with foo but no index starts with bar. NOTE: This option is only supported when specifying an index expression. You will get an error if you specify index options to the _resolve/cluster API endpoint that takes no index expression.

  • expand_wildcards string | array[string]

    Type of index that wildcard patterns can match. If the request can target data streams, this argument determines whether wildcard expressions match hidden data streams. Supports comma-separated values, such as open,hidden. Valid values are: all, open, closed, hidden, none. NOTE: This option is only supported when specifying an index expression. You will get an error if you specify index options to the _resolve/cluster API endpoint that takes no index expression.

  • ignore_throttled boolean Deprecated

    If true, concrete, expanded, or aliased indices are ignored when frozen. NOTE: This option is only supported when specifying an index expression. You will get an error if you specify index options to the _resolve/cluster API endpoint that takes no index expression.

  • If false, the request returns an error if it targets a missing or closed index. NOTE: This option is only supported when specifying an index expression. You will get an error if you specify index options to the _resolve/cluster API endpoint that takes no index expression.

  • timeout string

    The maximum time to wait for remote clusters to respond. If a remote cluster does not respond within this timeout period, the API response will show the cluster as not connected and include an error message that the request timed out.

    The default timeout is unset and the query can take as long as the networking layer is configured to wait for remote clusters that are not responding (typically 30 seconds).

Responses

  • 200 application/json
    Hide response attribute Show response attribute object
    • * object Additional properties

      Additional properties are allowed.

      Hide * attributes Show * attributes object
GET /_resolve/cluster/{name}
curl \
 --request GET http://api.example.com/_resolve/cluster/{name}
Response examples (200)
A successful response from `GET /_resolve/cluster/my-index*,clust*:my-index*`. Each cluster has its own response section. The cluster you sent the request to is labelled as "(local)".
{
  "(local)": {
    "connected": true,
    "skip_unavailable": false,
    "matching_indices": true,
    "version": {
      "number": "8.13.0",
      "build_flavor": "default",
      "minimum_wire_compatibility_version": "7.17.0",
      "minimum_index_compatibility_version": "7.0.0"
    }
  },
  "cluster_one": {
    "connected": true,
    "skip_unavailable": true,
    "matching_indices": true,
    "version": {
      "number": "8.13.0",
      "build_flavor": "default",
      "minimum_wire_compatibility_version": "7.17.0",
      "minimum_index_compatibility_version": "7.0.0"
    }
  },
  "cluster_two": {
    "connected": true,
    "skip_unavailable": false,
    "matching_indices": true,
    "version": {
      "number": "8.13.0",
      "build_flavor": "default",
      "minimum_wire_compatibility_version": "7.17.0",
      "minimum_index_compatibility_version": "7.0.0"
    }
  }
}
A successful response from `GET /_resolve/cluster/not-present,clust*:my-index*,oldcluster:*?ignore_unavailable=false&timeout=5s`. This type of request can be used to identify potential problems with your cross-cluster search. Note also that a `timeout` of 5 seconds is sent, which sets the maximum time the query will wait for remote clusters to respond. The local cluster has no index called `not_present`. Searching with `ignore_unavailable=false` would return a "no such index" error. The `cluster_one` remote cluster has no indices that match the pattern `my-index*`. There may be no indices that match the pattern or the index could be closed. The `cluster_two` remote cluster is not connected (the attempt to connect failed). Since this cluster is marked as `skip_unavailable=false`, you should probably exclude this cluster from the search by adding `-cluster_two:*` to the search index expression. For `cluster_three`, the error message indicates that this remote cluster did not respond within the 5-second timeout window specified, so it is also marked as not connected. The `oldcluster` remote cluster shows that it has matching indices, but no version information is included. This indicates that the cluster version predates the introduction of the `_resolve/cluster` API, so you may want to exclude it from your cross-cluster search.
{
  "(local)": {
    "connected": true,
    "skip_unavailable": false,
    "error": "no such index [not_present]"
  },
  "cluster_one": {
    "connected": true,
    "skip_unavailable": true,
    "matching_indices": false,
    "version": {
      "number": "8.13.0",
      "build_flavor": "default",
      "minimum_wire_compatibility_version": "7.17.0",
      "minimum_index_compatibility_version": "7.0.0"
    }
  },
  "cluster_two": {
    "connected": false,
    "skip_unavailable": false
  },
  "cluster_three": {
    "connected": false,
    "skip_unavailable": false,
    "error": "Request timed out before receiving a response from the remote cluster"
  },
  "oldcluster": {
    "connected": true,
    "skip_unavailable": false,
    "matching_indices": true
  }
}