corosync-quorumtool

corosync-quorumtool is a command-line utility used to query and manage the quorum state in a Corosync-based cluster. It allows you to check the quorum status, identify the cluster's quorum members, and display the current voting status. This tool is especially useful for diagnosing quorum-related issues and ensuring that your cluster has an active majority of nodes required for proper operation.

Purpose

• Monitor Quorum Status: Provides real-time information about the quorum status in a Corosync cluster, including the number of nodes in the quorum and the current leader.

• Diagnose Quorum Failures: Helps identify quorum issues by displaying which nodes are currently in or out of quorum, making it easier to troubleshoot cluster communication problems.

• Display Cluster Members: Lists the nodes participating in the cluster and their status with respect to quorum.

Basic Syntax

corosync-quorumtool [OPTIONS]

• No Arguments: Running the tool without any options shows the current quorum status.

  Example:

  corosync-quorumtool

• Display Quorum Information: To get the quorum information, including the number of nodes in quorum, the tool outputs a status message.

  Example output:

  Quorum information:
  -------------------
  Last updated:     Thu Mar 10 13:17:31 2025
  Last change:      Thu Mar 10 13:17:30 2025
  Cluster name:     corosync
  Membership information:
   Member ID: 0 (node1)
     Status: in quorum
   Member ID: 1 (node2)
     Status: in quorum
   Member ID: 2 (node3)
     Status: in quorum

Common Options

• -v, --verbose Display detailed quorum information, including the status of all nodes.

  Example:

  corosync-quorumtool -v

• -h, --help Show help information about the command.

  Example:

  corosync-quorumtool --help

Example Usage

1. Check Quorum Status

   corosync-quorumtool

   This command provides the current quorum status of the cluster, listing all nodes and whether they are in quorum or not.

2. Verbose Quorum Information

   corosync-quorumtool -v

   This command provides a more detailed view, including the cluster's voting members and their states.

3. Check Quorum after a Node Failure

   If a node fails and the cluster may have lost quorum, running this command helps identify which nodes are still part of the quorum and which are out of it.

Best Practices

• Monitor Quorum Regularly: Regularly check the quorum status to ensure your cluster remains healthy, especially in larger clusters or in environments with frequent node additions or failures.

• Use During Troubleshooting: In case of a failure or issues with cluster communication, corosync-quorumtool can be used to quickly determine whether quorum has been lost and which nodes are still part of the quorum.

• Ensure Proper Node Configuration: Properly configure your nodes to avoid split-brain scenarios and ensure that a majority of nodes are always in quorum.

Conclusion

corosync-quorumtool is an essential tool for maintaining the health and stability of a Corosync-based cluster. It enables administrators to check quorum status, view membership details, and diagnose quorum-related issues, ensuring that the cluster remains in a consistent and highly available state.