Rook (Ceph Operator) RBD mirroring fails due to configuration errors or network issues.

What is Rook (Ceph Operator) RBD mirroring fails due to configuration errors or network issues.

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 solution offering 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: RBD_MIRRORING_FAILED

When using Rook with Ceph, you might encounter the error code RBD_MIRRORING_FAILED. This error indicates that the RBD (RADOS Block Device) mirroring process has failed. RBD mirroring is used to asynchronously replicate block device images between Ceph clusters, providing disaster recovery capabilities.

Observed Behavior

Users may notice that RBD images are not being mirrored as expected. This could manifest as data not being available on the secondary cluster, or error logs indicating mirroring failures.

Exploring the Issue: RBD_MIRRORING_FAILED

The RBD_MIRRORING_FAILED error typically arises due to configuration errors or network issues. It is crucial to ensure that the mirroring configuration is correctly set up and that there is proper network connectivity between the primary and secondary clusters.

Common Causes

Incorrect mirroring configuration settings. Network connectivity issues between clusters. Authentication problems with Ceph clients. Outdated or incompatible Ceph versions.

Steps to Fix the RBD_MIRRORING_FAILED Issue

To resolve the RBD_MIRRORING_FAILED error, follow these steps:

1. Verify Mirroring Configuration

Ensure that the mirroring configuration is correctly set up. Check the following:

Verify that the RBD images are enabled for mirroring using the command: rbd mirror image status <pool-name>/<image-name> Ensure that the mirroring mode is set correctly. Use the command: rbd mirror image enable <pool-name>/<image-name> <mode>

2. Check Network Connectivity

Ensure that there is proper network connectivity between the primary and secondary clusters. You can test connectivity using tools like ping or telnet to verify that the clusters can communicate over the required ports.

3. Review Authentication Settings

Check that the Ceph clients have the necessary permissions and that the authentication keys are correctly configured. You can review the client capabilities using:

ceph auth get client.<client-name>

4. Update Ceph Versions

Ensure that both clusters are running compatible versions of Ceph. If there are version mismatches, consider upgrading to a compatible version. Refer to the Ceph release notes for guidance on version compatibility.

Additional Resources

For more detailed information, refer to the following resources:

Rook Ceph Block Storage Documentation Ceph RBD Mirroring Guide Kubernetes Storage Concepts