Troubleshooting Kubernetes
Troubleshooting is a crucial skill for managing Kubernetes clusters. This section provides strategies and tools for diagnosing and resolving common issues.
Common Issues and Solutions
| Issue |
Description |
Solution |
| CrashLoopBackOff |
Pod repeatedly crashing. |
Check logs with kubectl logs <pod-name>. |
| ImagePullBackOff |
Kubernetes cannot pull the container image. |
Verify the image name and credentials. |
| Node Not Ready |
Node is not functioning correctly. |
Check node status with kubectl get nodes and review the kubelet logs. |
| Disk Pressure |
Node runs low on disk space. |
Free up space or add more storage. |
| Service Not Accessible |
Service configuration or endpoints issue. |
Check service configuration with kubectl get svc and kubectl describe svc <service-name>. |
| DNS Resolution Failures |
DNS pod status or configuration issue. |
Verify DNS pod status and configuration with kubectl get pods -n kube-system. |
| Pod Eviction |
Pods are evicted due to resource constraints. |
Check node resource usage and adjust limits or requests. |
| High CPU Usage |
Pods or nodes experiencing high CPU usage. |
Analyze CPU usage with kubectl top and optimize application resource requests. |
| Network Latency |
High latency in network communication between Pods. |
Check network policies and configurations, and ensure sufficient bandwidth. |
| Command |
Description |
Example Usage |
describe |
Provides detailed information about resources. |
kubectl describe pod <pod-name> |
logs |
Retrieves logs from containers. |
kubectl logs <pod-name> |
exec |
Executes commands in a container. |
kubectl exec -it <pod-name> -- /bin/sh |
Monitoring and Logging
- Prometheus: Collects metrics and provides alerts. It's highly customizable and integrates well with Kubernetes. Learn more
- Grafana: Visualizes metrics collected by Prometheus and other sources. It offers a rich set of dashboards and visualization tools. Learn more
- Elasticsearch, Fluentd, Kibana (EFK) Stack: Centralizes logging and provides search capabilities. Elasticsearch stores logs, Fluentd collects and forwards them, and Kibana visualizes the data. Learn more about Elasticsearch, Fluentd, Kibana
Best Practices
- Regular Monitoring: Continuously monitor cluster health and performance.
- Automated Alerts: Set up alerts for critical issues to ensure timely response.
- Documentation: Keep detailed records of issues and solutions for future reference.