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Nodes info

The nodes info API represents mostly static information about your cluster’s nodes, including but not limited to:

  • Host system information
  • JVM
  • Processor Type
  • Node settings
  • Thread pools settings
  • Installed plugins

Example

To get information about all nodes in a cluster, use the following query:

GET /_nodes

To get thread pool information about the cluster manager node only, use the following query:

GET /_nodes/master:true/thread_pool

Path and HTTP methods

GET /_nodes
GET /_nodes/<nodeId>
GET /_nodes/<metrics>
GET /_nodes/<nodeId>/<metrics>
# or full path equivalent
GET /_nodes/<nodeId>/info/<metrics>

Path parameters

The following table lists the available path parameters. All path parameters are optional.

Parameter Type Description
nodeId String A comma-separated list of nodeIds used to filter results. Supports node filters. Defaults to _all.
metrics String A comma-separated list of metric groups that will be included in the response. For example, jvm,thread_pool. Defaults to all metrics.

The following table lists all available metric groups.

Metric Description
settings A node’s settings. This is a combination of the default settings, custom settings from the configuration file, and dynamically updated settings.
os Static information about the host OS, including version, processor architecture, and available/allocated processors.
process Contains the process ID.
jvm Detailed static information about the running JVM, including arguments.
thread_pool Configured options for all individual thread pools.
transport Mostly static information about the transport layer.
http Mostly static information about the HTTP layer.
plugins Information about installed plugins and modules.
ingest Information about ingest pipelines and available ingest processors.
aggregations Information about available aggregations.
indices Static index settings configured at the node level.

Query parameters

You can include the following query parameters in your request. All query parameters are optional.

Parameter Type Description
flat_settings Boolean Specifies whether to return the settings object of the response in flat format. Default is false.
timeout Time Sets the time limit for node response. Default value is 30s.

Sample request

The following query requests the process and transport metrics from the cluster manager node:

GET /_nodes/cluster_manager:true/process,transport

Sample response

The response contains the metric groups specified in the <metrics> request parameter (in this case, process and transport):

{
  "_nodes": {
    "total": 1,
    "successful": 1,
    "failed": 0
  },
  "cluster_name": "opensearch",
  "nodes": {
    "VC0d4RgbTM6kLDwuud2XZQ": {
      "name": "node-m1-23",
      "transport_address": "127.0.0.1:9300",
      "host": "127.0.0.1",
      "ip": "127.0.0.1",
      "version": "1.3.1",
      "build_type": "tar",
      "build_hash": "c4c0672877bf0f787ca857c7c37b775967f93d81",
      "roles": [
        "data",
        "ingest",
        "master",
        "remote_cluster_client"
      ],
      "attributes": {
        "shard_indexing_pressure_enabled": "true"
      },
      "process" : {
        "refresh_interval_in_millis": 1000,
        "id": 44584,
        "mlockall": false
      },
      "transport": {
        "bound_address": [
          "[::1]:9300",
          "127.0.0.1:9300"
        ],
        "publish_address": "127.0.0.1:9300",
        "profiles": { }
      }
    }
  }
}

Response fields

The response contains the basic node identification and build info for every node matching the <nodeId> request parameter. The following table lists the response fields.

Field Description
name The node’s name.
transport_address The node’s transport address.
host The node’s host address.
ip The node’s host IP address.
version The node’s OpenSearch version.
build_type The node’s build type, like rpm, docker, tar, etc.
build_hash The git commit hash of the build.
total_indexing_buffer The maximum heap size in bytes used to hold newly indexed documents. Once this heap size is exceeded, the documents are written to disk.
roles The list of the node’s roles.
attributes The node’s attributes.
os Information about the OS, including name, version, architecture, refresh interval, and the number of available and allocated processors.
process Information about the currently running process, including PID, refresh interval, and mlockall, which specifies whether the process address space has been successfully locked in memory.
jvm Information about the JVM, including PID, version, memory information, garbage collector information, and arguments.
thread_pool Information about the thread pool.
transport Information about the transport address, including bound address, publish address, and profiles.
http Information about the HTTP address, including bound address, publish address, and maximum content length, in bytes.
plugins Information about the installed plugins, including name, version, OpenSearch version, Java version, description, class name, custom folder name, a list of extended plugins, and has_native_controller, which specifies whether the plugin has a native controller process.
modules Information about the modules, including name, version, OpenSearch version, Java version, description, class name, custom folder name, a list of extended plugins, and has_native_controller, which specifies whether the plugin has a native controller process. Modules are different from plugins because modules are loaded into OpenSearch automatically, while plugins have to be installed manually.
ingest Information about ingest pipelines and processors.
aggregations Information about the available aggregation types.

Required permissions

If you use the security plugin, make sure you have the appropriate permissions: cluster:monitor/nodes/info.