Troubleshooting Quick Reference

Purpose: Quick reference for common troubleshooting commands and patterns.

Quick Command Reference

Pod Information

# List pods
kubectl get pods -A
kubectl get pods -n [namespace] -o wide

# Pod details
kubectl describe pod [pod-name] -n [namespace]

# Pod logs
kubectl logs [pod-name] -n [namespace]
kubectl logs [pod-name] -n [namespace] --previous
kubectl logs [pod-name] -n [namespace] --tail=100 -f

# Pod YAML
kubectl get pod [pod-name] -n [namespace] -o yaml

Service Information

# List services
kubectl get svc -A
kubectl get svc -n [namespace]

# Service details
kubectl describe svc [service-name] -n [namespace]

# Service endpoints
kubectl get endpoints [service-name] -n [namespace]

Resource Information

# Resource usage
kubectl top pods -n [namespace]
kubectl top nodes

# Resource quotas
kubectl get resourcequota -n [namespace]
kubectl describe resourcequota [quota-name] -n [namespace]

# Resource requests/limits
kubectl get pod [pod-name] -n [namespace] -o jsonpath='{.spec.containers[*].resources}'

Network Information

# Network policies
kubectl get networkpolicies -n [namespace]
kubectl describe networkpolicy [policy-name] -n [namespace]

# Test connectivity
kubectl exec [pod-name] -n [namespace] -- wget -O- http://[service]
kubectl exec [pod-name] -n [namespace] -- ping [host]

# DNS test
kubectl exec [pod-name] -n [namespace] -- nslookup [service]
kubectl exec [pod-name] -n [namespace] -- cat /etc/resolv.conf

RBAC Information

# Roles and bindings
kubectl get role,rolebinding -n [namespace]
kubectl describe role [role-name] -n [namespace]

# Service accounts
kubectl get serviceaccount -n [namespace]
kubectl describe serviceaccount [sa-name] -n [namespace]

# Test permissions
kubectl auth can-i [verb] [resource] --namespace=[namespace] --as=system:serviceaccount:[ns]:[sa]

Events and Logs

# Events
kubectl get events --sort-by='.lastTimestamp'
kubectl get events -n [namespace] --sort-by='.lastTimestamp'

# Recent events
kubectl get events -n [namespace] --field-selector involvedObject.name=[pod-name]

Configuration

# ConfigMaps
kubectl get configmap -n [namespace]
kubectl get configmap [name] -n [namespace] -o yaml

# Secrets
kubectl get secret -n [namespace]
kubectl get secret [name] -n [namespace] -o yaml

# Decode secret
kubectl get secret [name] -n [namespace] -o jsonpath='{.data.[key]}' | base64 -d

Common Issue Patterns

Pod Not Starting

Quick Checks:

kubectl get pods -n [namespace]
kubectl describe pod [pod-name] -n [namespace]
kubectl get events -n [namespace] --field-selector involvedObject.name=[pod-name]

Common Causes:

• Image pull failure
• Resource constraints
• Configuration errors
• Permission issues

Pod Crash Looping

Quick Checks:

kubectl logs [pod-name] -n [namespace] --previous
kubectl describe pod [pod-name] -n [namespace]
kubectl get events -n [namespace] --field-selector involvedObject.name=[pod-name]

Common Causes:

• Application errors
• Resource limits exceeded
• Configuration errors
• Missing dependencies

Service Unreachable

Quick Checks:

kubectl get endpoints [service-name] -n [namespace]
kubectl get networkpolicies -n [namespace]
kubectl exec [pod-name] -n [namespace] -- wget -O- http://[service]

Common Causes:

• No endpoints
• Network policy blocking
• DNS issues
• Service misconfiguration

High Resource Usage

Quick Checks:

kubectl top pods -n [namespace]
kubectl top nodes
kubectl get resourcequota -n [namespace]
kubectl describe pod [pod-name] -n [namespace] | grep -A 5 Limits

Common Causes:

• Resource limits too low
• Resource quota exhausted
• Memory leaks
• High load

Diagnostic Workflows

Network Issue Workflow

1. Check pod status
2. Check service endpoints
3. Test connectivity
4. Check network policies
5. Verify DNS

Resource Issue Workflow

1. Check pod status
2. Check resource usage
3. Check resource quotas
4. Check node capacity
5. Review resource requests/limits

Permission Issue Workflow

1. Check pod logs
2. Check service account
3. Check RBAC configuration
4. Test permissions
5. Verify role bindings

Image Pull Issue Workflow

1. Check pod events
2. Verify image name
3. Check image pull secrets
4. Test image pull
5. Verify registry access

Quick Fixes

Restart Pod

kubectl delete pod [pod-name] -n [namespace]
# Pod will be recreated if part of Deployment

Scale Deployment

kubectl scale deployment [name] --replicas=[count] -n [namespace]

Update Image

kubectl set image deployment/[name] [container]=[image]:[tag] -n [namespace]

Rollback Deployment

kubectl rollout undo deployment/[name] -n [namespace]

Delete Network Policy

kubectl delete networkpolicy [name] -n [namespace]

Increase Resource Quota

kubectl patch resourcequota [name] -n [namespace] --type merge -p '{"spec":{"hard":{"memory":"2Gi"}}}'

Emergency Commands

Get Everything

kubectl get all -n [namespace]

Describe Everything

kubectl describe all -n [namespace]

Export Everything

kubectl get all -n [namespace] -o yaml > backup.yaml

Delete Everything (Careful!)

kubectl delete all --all -n [namespace]

Related Documentation

• Systematic Debugging
• Common Patterns
• Escalation Guide

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Remember: This is a quick reference. For detailed procedures, see the scenario guides and systematic debugging methodology.