> For the complete documentation index, see [llms.txt](https://linux-tutorial-cli.gitbook.io/linux-cli-tutorial/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://linux-tutorial-cli.gitbook.io/linux-cli-tutorial/txt-files/file-systems-cocepts/lpic3-306/crm_node.md).

# crm\_node

`crm_node` is a command-line tool from the crmsh suite used to query and manage node information in Pacemaker-based clusters. It focuses on listing cluster nodes, displaying their status, and sometimes allowing for basic node-level operations or attribute adjustments. This tool helps administrators verify the cluster membership and diagnose node-related issues.

## Purpose

* **Node Querying:**\
  Retrieve and display a list of nodes that are part of the cluster, along with their status (e.g., online, standby, offline).
* **Cluster Health Monitoring:**\
  Quickly assess the overall health of cluster nodes, which is essential for troubleshooting and ensuring that the cluster maintains quorum.
* **Node Management:**\
  In some cases, it may allow for basic management operations such as setting a node into standby mode or querying node attributes.

## Basic Syntax

```bash
crm_node [options] [command] [arguments]
```

### Common Operations

* **Listing Nodes:**

  ```bash
  crm_node --list
  ```

  This command outputs a list of all nodes currently recognized in the cluster.
* **Querying Node Status:**

  ```bash
  crm_node --status <node_name>
  ```

  Replace `<node_name>` with the name or identifier of the node to display detailed status information, such as whether the node is online, its current role, and any relevant attributes.
* **Help and Documentation:**

  ```bash
  crm_node --help
  ```

  Displays available commands, options, and usage details for the tool.

## Example Usage

1. **List All Nodes in the Cluster:**

   ```bash
   crm_node --list
   ```

   This command shows a summary of each node's presence in the cluster, making it easier to identify nodes that may be offline or not responding.
2. **Display Detailed Status for a Specific Node:**

   ```bash
   crm_node --status node1
   ```

   Replace `node1` with the actual node name to see more detailed information such as the node's connectivity, roles, and any attributes set for that node.

## Conclusion

`crm_node` is an essential tool for cluster administrators working with Pacemaker-managed environments. It provides a straightforward way to monitor and verify the nodes within a cluster, ensuring that all members are operating correctly and contributing to cluster quorum. For further details or advanced usage, you can refer to the built-in help documentation by running:

```bash
crm_node --help
```

This tool, alongside other crmsh utilities, helps maintain the overall health and stability of high-availability clusters by giving administrators direct insight into node status and configuration.