Rook is an open-source cloud-native storage orchestrator for Kubernetes, providing a platform, framework, and support for Ceph storage systems. It automates the deployment, configuration, and management of Ceph clusters, enabling users to easily integrate storage solutions into their Kubernetes environments.
When working with Rook, you might encounter the issue where a monitor pod is not running. This is typically indicated by the error code MON_POD_NOT_RUNNING. This symptom is observed when the Ceph monitor pods fail to start or remain in a pending state.
The primary cause of the MON_POD_NOT_RUNNING issue is related to startup problems or insufficient resources allocated to the monitor pods. This can happen due to various reasons such as misconfigurations, lack of CPU or memory resources, or network issues.
When monitor pods are not running, the Ceph cluster's health is compromised, affecting the overall storage operations and potentially leading to data unavailability or loss.
Start by examining the logs of the monitor pods to identify any errors or warnings that might indicate the root cause. Use the following command to view the logs:
kubectl logs -n rook-ceph
Look for specific error messages that can guide you towards the underlying issue.
Ensure that the monitor pods have sufficient resources allocated. Check the resource requests and limits in the CephCluster resource:
kubectl get cephcluster -n rook-ceph -o yaml
Adjust the resource requests and limits if necessary to provide adequate CPU and memory.
Verify that the nodes where the monitor pods are scheduled have enough resources and are in a healthy state. Use the following command to check node conditions:
kubectl describe nodes
Ensure there are no taints or conditions preventing the pods from running.
Ensure that the network configuration allows communication between the monitor pods and other components of the Ceph cluster. Check for any network policies or firewall rules that might be blocking traffic.
For more detailed information on troubleshooting Rook Ceph issues, refer to the official Rook Documentation. Additionally, the Ceph Documentation provides comprehensive guidance on managing Ceph clusters.
(Perfect for DevOps & SREs)
(Perfect for DevOps & SREs)
