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.

Tools for Troubleshooting

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.

Summary

  • Troubleshooting is a core skill for any Kubernetes admin.
  • Use kubectl commands, logs, and monitoring tools to diagnose issues.
  • Document common issues and solutions for your team.

Tip

Build a troubleshooting playbook and share it with your team. Review and update it after every incident.