nodeId | String | A comma-separated list of nodeIds used to filter results. Supports [node filters]({{site.url}}{{site.baseurl}}/opensearch/rest-api/nodes-apis/index/#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.
settings | A node's settings. This is a combination of the default settings, custom settings from the [configuration file]({{site.url}}{{site.baseurl}}/opensearch/configuration/#configuration-file), and dynamically [updated settings]({{site.url}}{{site.baseurl}}/opensearch/configuration/#update-cluster-settings-using-the-api).
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]({{site.url}}{{site.baseurl}}/opensearch/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`.
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.
