Rook (Ceph Operator) CephFS mount fails during operation.

What is Rook (Ceph Operator) CephFS mount fails during operation.

Understanding Rook (Ceph Operator)

Rook is an open-source cloud-native storage orchestrator for Kubernetes, providing a framework to run Ceph storage systems on Kubernetes clusters. Ceph is a highly scalable distributed storage system that provides object, block, and file storage in a unified system. Rook automates the deployment, configuration, and management of Ceph clusters, making it easier to integrate storage solutions into Kubernetes environments.

Identifying the Symptom: CephFS Mount Failure

One common issue encountered when using Rook with Ceph is the failure to mount CephFS, the Ceph file system. Users may observe error messages indicating that the mount operation has failed, which can disrupt access to the file system and affect applications relying on it.

Common Error Messages

mount error: could not resolve address for ceph-mon: Name or service not known mount error: connection timed out

Exploring the Issue: CEPHFS_MOUNT_FAILURE

The CEPHFS_MOUNT_FAILURE error typically arises due to network connectivity issues or incorrect mount options. This can occur if the Ceph monitors are unreachable or if there are misconfigurations in the mount command.

Potential Causes

Network connectivity problems between the client and Ceph monitors. Incorrect or missing mount options in the command. Firewall rules blocking necessary ports for Ceph communication.

Steps to Resolve the CephFS Mount Failure

To address the CEPHFS_MOUNT_FAILURE, follow these steps:

1. Verify Network Connectivity

Ensure that the client can reach the Ceph monitors. Use the following command to test connectivity:

ping <ceph-mon-ip>

If the ping fails, check your network configuration and ensure that there are no firewalls blocking the connection.

2. Check Mount Options

Review the mount command options. A typical mount command looks like this:

mount -t ceph <mon-ip>:/ /mnt/cephfs -o name=<username>,secret=<secret>

Ensure that the monitor IPs, username, and secret are correctly specified. Refer to the Ceph documentation for more details on mount options.

3. Review Firewall Settings

Ensure that the necessary ports for Ceph communication are open. Ceph typically uses ports 6789 and 3300 for monitor communication. Use the following command to check open ports:

sudo iptables -L -n

Adjust your firewall settings if necessary to allow traffic on these ports.

Conclusion

By following these steps, you should be able to resolve the CEPHFS_MOUNT_FAILURE and successfully mount CephFS. For further assistance, consider consulting the Rook documentation or the Ceph community resources.