Troubleshooting Guide

Diagnostic Workflow

graph TD
    Issue[Issue Detected] --> Triage[Triage]
    Triage --> Diagnose[Diagnose]
    Diagnose --> Fix[Apply Fix]
    Fix --> Verify[Verify]
    Verify --> Document[Document]

Common Issues

1. Cluster Health Issues

Node Problems

graph TD
    Node[Node Issue] --> Check[Check Status]
    Check --> |Healthy| Resources[Resource Issue]
    Check --> |Unhealthy| System[System Issue]
    Resources --> Memory[Memory]
    Resources --> CPU[CPU]
    Resources --> Disk[Disk]
    System --> Logs[Check Logs]
    System --> Network[Network]

Diagnosis Steps:

# Check node status
kubectl get nodes
kubectl describe node <node-name>

# Check system resources
kubectl top nodes
kubectl top pods --all-namespaces

# Check system logs
kubectl logs -n kube-system <pod-name>

2. Storage Issues

Volume Problems

graph LR
    PV[PV Issue] --> Status[Check Status]
    Status --> |Bound| Access[Access Issue]
    Status --> |Pending| Provision[Provisioning Issue]
    Status --> |Failed| Storage[Storage System]

Resolution Steps:

# Check PV/PVC status
kubectl get pv,pvc --all-namespaces

# Check storage class
kubectl get sc

# Check provisioner pods
kubectl get pods -n storage

3. Network Issues

Connectivity Problems

graph TD
    Net[Network Issue] --> DNS[DNS Check]
    Net --> Ingress[Ingress Check]
    Net --> Policy[Network Policy]

    DNS --> CoreDNS[CoreDNS Pods]
    Ingress --> Traefik[Traefik Logs]
    Policy --> Rules[Policy Rules]

Diagnostic Commands:

# Check DNS
kubectl get pods -n kube-system -l k8s-app=kube-dns
kubectl logs -n kube-system -l k8s-app=kube-dns

# Check ingress
kubectl get ingress --all-namespaces
kubectl describe ingress <ingress-name> -n <namespace>

4. Application Issues

Pod Problems

graph TD
    Pod[Pod Issue] --> Status[Check Status]
    Status --> |Pending| Schedule[Scheduling]
    Status --> |CrashLoop| Crash[Container Crash]
    Status --> |Error| Logs[Check Logs]

Troubleshooting Steps:

# Check pod status
kubectl get pods -n <namespace>
kubectl describe pod <pod-name> -n <namespace>

# Check logs
kubectl logs <pod-name> -n <namespace>
kubectl logs <pod-name> -n <namespace> --previous

Flux Issues

GitOps Troubleshooting

graph TD
    Flux[Flux Issue] --> Source[Source Controller]
    Flux --> Kust[Kustomize Controller]
    Flux --> Helm[Helm Controller]

    Source --> Git[Git Repository]
    Kust --> Sync[Sync Status]
    Helm --> Release[Release Status]

Resolution Steps:

# Check Flux components
flux check

# Check sources
flux get sources git
flux get sources helm

# Check reconciliation
flux get kustomizations
flux get helmreleases

Performance Issues

Resource Constraints

graph LR
    Perf[Performance] --> CPU[CPU Usage]
    Perf --> Memory[Memory Usage]
    Perf --> IO[I/O Usage]

    CPU --> Limit[Resource Limits]
    Memory --> Constraint[Memory Constraints]
    IO --> Bottleneck[I/O Bottleneck]

Analysis Commands:

# Check resource usage
kubectl top pods -n <namespace>
kubectl top nodes

# Check resource quotas
kubectl get resourcequota -n <namespace>

Recovery Procedures

1. Node Recovery

  1. Drain node
  2. Perform maintenance
  3. Uncordon node
  4. Verify workloads

2. Storage Recovery

  1. Backup data
  2. Fix storage issues
  3. Restore data
  4. Verify access

3. Network Recovery

  1. Check connectivity
  2. Verify DNS
  3. Test ingress
  4. Update policies

Best Practices

1. Logging

  • Maintain detailed logs
  • Set appropriate retention
  • Use structured logging
  • Enable audit logging

2. Monitoring

  • Set up alerts
  • Monitor resources
  • Track metrics
  • Use dashboards

3. Documentation

  • Document issues
  • Record solutions
  • Update procedures
  • Share knowledge

Emergency Procedures

Critical Issues

  1. Assess impact
  2. Implement temporary fix
  3. Plan permanent solution
  4. Update documentation

Contact Information

  • Maintain escalation paths
  • Keep contact list updated
  • Document response times
  • Track incidents