Rook is an open-source cloud-native storage orchestrator for Kubernetes, providing a framework to run Ceph storage systems. The Rook operator automates the deployment, configuration, and management of Ceph clusters, making it easier to manage storage in a Kubernetes environment. Ceph is a highly scalable distributed storage system that provides object, block, and file storage in a unified system.
When working with Rook (Ceph Operator), you might encounter the error MGR_DAEMON_NOT_RUNNING. This indicates that the Ceph Manager (MGR) daemon is not running, which can lead to issues with monitoring and managing the Ceph cluster.
The Ceph Manager daemon is responsible for monitoring the cluster's state and providing an interface for management tools. It collects and exposes metrics, manages the dashboard, and handles other administrative tasks.
The MGR_DAEMON_NOT_RUNNING error can occur due to several reasons, including configuration errors, insufficient resources, or issues with the Kubernetes environment.
First, inspect the logs of the manager pod to identify any errors or warnings. Use the following command to view the logs:
kubectl logs -n rook-ceph -l app=rook-ceph-mgr
Look for any error messages that might indicate the root cause of the issue.
Ensure that the Ceph cluster configuration is correct. Check the CephCluster custom resource definition (CRD) for any misconfigurations. You can view the current configuration with:
kubectl get cephcluster -n rook-ceph -o yaml
Verify that all necessary fields are correctly set and that there are no typos or missing values.
Check if the manager pod has sufficient resources to run. You can describe the pod to see its resource requests and limits:
kubectl describe pod -n rook-ceph -l app=rook-ceph-mgr
If the pod is resource-constrained, consider increasing the CPU and memory limits in the CephCluster CRD.
For more detailed information on troubleshooting Rook (Ceph Operator), consider visiting the following resources:
By following these steps and utilizing the resources provided, you should be able to resolve the MGR_DAEMON_NOT_RUNNING issue and ensure your Ceph cluster is functioning correctly.
(Perfect for DevOps & SREs)
(Perfect for DevOps & SREs)
