Rook is an open-source cloud-native storage orchestrator for Kubernetes that leverages the Ceph storage system. It automates the deployment, configuration, and management of Ceph clusters, providing a seamless storage solution for Kubernetes applications. The Ceph Operator in Rook manages the lifecycle of Ceph clusters, ensuring high availability and scalability of storage resources.
When using Rook with Ceph, you might encounter an issue where the Ceph manager modules are not running. This is typically indicated by the error code MGR_MODULES_NOT_RUNNING. The Ceph manager is responsible for handling various management tasks and providing a dashboard for monitoring the cluster's health and performance.
The error MGR_MODULES_NOT_RUNNING suggests that the Ceph manager modules are not active. This can occur due to misconfigurations or insufficient resources allocated to the manager pods. Without these modules running, you might experience limited functionality in managing and monitoring your Ceph cluster.
To resolve this issue, follow these steps:
First, inspect the logs of the Ceph manager pods to identify any errors or warnings that might indicate the cause of the issue. Use the following command to view the logs:
kubectl logs -n rook-ceph -l app=rook-ceph-mgr
Look for any error messages or indications of misconfiguration.
Ensure that the manager modules are correctly configured in your Ceph cluster. Check the Ceph configuration files or use the Ceph CLI to verify the module settings:
ceph mgr module ls
Ensure that all necessary modules are enabled and properly configured.
Verify that the manager pods have adequate resources allocated. Check the resource requests and limits in the CephCluster custom resource definition (CRD):
kubectl describe cephcluster -n rook-ceph
Adjust the resource allocations if necessary to ensure the manager pods have enough CPU and memory.
Ensure that there are no network issues preventing the manager modules from communicating with other Ceph components. Verify the network policies and firewall settings in your Kubernetes cluster.
For more information on managing Ceph clusters with Rook, refer to the following resources:
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