Kubernetes Cheatsheet

The kubectl commands you’ll actually type day to day, plus debugging workflows for when things go sideways.

Context & Namespace

# List all contexts
kubectl config get-contexts

# Switch context
kubectl config use-context staging
# or with krew ctx plugin
kubectl ctx staging

# Set default namespace
kubectl config set-context --current --namespace=my-app
# or with krew ns plugin
kubectl ns my-app

# See current context and namespace
kubectl config current-context

Getting Resources

# Pods
kubectl get pods                     # current namespace
kubectl get pods -A                  # all namespaces
kubectl get pods -o wide             # more detail (node, IP)
kubectl get pods -w                  # watch for changes
kubectl get pods -l app=api          # filter by label

# Common resources
kubectl get svc                      # services
kubectl get deploy                   # deployments
kubectl get ing                      # ingresses
kubectl get cm                       # configmaps
kubectl get secret                   # secrets
kubectl get pvc                      # persistent volume claims
kubectl get nodes                    # cluster nodes
kubectl get events --sort-by='.lastTimestamp'  # recent events

# All resources in a namespace
kubectl get all

# Custom output
kubectl get pods -o json             # full JSON
kubectl get pods -o yaml             # full YAML
kubectl get pods -o name             # just names
kubectl get pods -o jsonpath='{.items[*].metadata.name}'  # jsonpath

Describing & Inspecting

# Describe a resource (shows events, conditions, config)
kubectl describe pod my-pod
kubectl describe node my-node
kubectl describe svc my-service

# Get YAML definition
kubectl get pod my-pod -o yaml

# Clean YAML output (with krew neat plugin)
kubectl get pod my-pod -o yaml | kubectl neat

# Show resource tree (with krew tree plugin)
kubectl tree deployment my-app

Logs

# Pod logs
kubectl logs my-pod
kubectl logs my-pod -c my-container  # specific container
kubectl logs my-pod --previous       # previous crashed container
kubectl logs my-pod -f               # follow/stream
kubectl logs my-pod --tail=50        # last 50 lines
kubectl logs my-pod --since=1h       # last hour

# stern (multi-pod tailing)
stern api                            # all pods matching "api"
stern api -c nginx                   # specific container
stern api -t                         # with timestamps
stern api --tail 10                  # last 10 lines
stern api -A                         # all namespaces
stern api -s 5m                      # last 5 minutes
stern api -o json                    # JSON output
stern api -e 'health'               # exclude lines matching pattern

Exec & Debug

# Shell into a running container
kubectl exec -it my-pod -- /bin/sh
kubectl exec -it my-pod -c my-container -- /bin/bash

# Run a one-off command
kubectl exec my-pod -- cat /etc/config/app.yaml

# Debug pod (creates ephemeral debug container)
kubectl debug -it my-pod --image=busybox

# Run a debug pod in the cluster
kubectl run debug --rm -it --image=busybox -- /bin/sh
kubectl run debug --rm -it --image=nicolaka/netshoot -- /bin/bash

# Port forward
kubectl port-forward pod/my-pod 8080:80
kubectl port-forward svc/my-service 8080:80
kubectl port-forward deploy/my-app 8080:80

Creating & Applying

# Apply a manifest
kubectl apply -f manifest.yaml
kubectl apply -f manifests/          # whole directory
kubectl apply -k overlays/staging/   # kustomize

# Create from command line
kubectl create namespace my-app
kubectl create configmap my-config --from-file=config.yaml
kubectl create secret generic my-secret --from-literal=key=value

# Dry run (see what would be applied)
kubectl apply -f manifest.yaml --dry-run=client -o yaml
kubectl apply -f manifest.yaml --dry-run=server -o yaml  # server-side validation

Scaling & Updating

# Scale deployment
kubectl scale deploy my-app --replicas=3

# Restart pods (rolling restart)
kubectl rollout restart deploy my-app

# Rollout status
kubectl rollout status deploy my-app

# Rollback
kubectl rollout undo deploy my-app
kubectl rollout undo deploy my-app --to-revision=3

# Rollout history
kubectl rollout history deploy my-app

Deleting

# Delete a resource
kubectl delete pod my-pod
kubectl delete -f manifest.yaml

# Force delete a stuck pod
kubectl delete pod my-pod --grace-period=0 --force

# Delete all pods in a namespace
kubectl delete pods --all

# Delete a namespace (and everything in it)
kubectl delete namespace my-app

Debugging Workflows

Pod Won’t Start

# 1. Check pod status
kubectl get pod my-pod

# 2. Check events
kubectl describe pod my-pod

# 3. Common statuses:
#    Pending     - no node can schedule it (resource limits, node selectors)
#    ImagePullBackOff - can't pull the image (wrong name, no auth)
#    CrashLoopBackOff - starts then crashes (check logs)
#    Init:Error  - init container failed

CrashLoopBackOff

# 1. Check logs from the crashed container
kubectl logs my-pod --previous

# 2. Check if it's an OOM kill
kubectl describe pod my-pod | grep -A5 "Last State"

# 3. Debug with an ephemeral container
kubectl debug -it my-pod --image=busybox

Service Not Reachable

# 1. Check the service exists and has endpoints
kubectl get svc my-service
kubectl get endpoints my-service

# 2. If no endpoints, check label selector matches pods
kubectl get svc my-service -o yaml | grep -A5 selector
kubectl get pods -l app=my-app

# 3. Test from inside the cluster
kubectl run debug --rm -it --image=busybox -- wget -qO- http://my-service:8080/health

# 4. Check network policies
kubectl get networkpolicy

DNS Issues

# Test DNS resolution from inside the cluster
kubectl run debug --rm -it --image=busybox -- nslookup my-service
kubectl run debug --rm -it --image=busybox -- nslookup my-service.my-namespace.svc.cluster.local

Node Issues

# Check node status and conditions
kubectl get nodes
kubectl describe node my-node

# Check resource usage
kubectl top nodes
kubectl top pods

# Check which pods are on a node
kubectl get pods --field-selector spec.nodeName=my-node -A

k9s Quick Reference

k9s                        # launch
k9s --context staging      # specific context
k9s -n kube-system         # specific namespace

Key	Action
:pods	View pods
:svc	View services
:deploy	View deployments
:ns	View namespaces
l	View logs
s	Shell into container
d	Describe resource
e	Edit resource
ctrl+d	Delete resource
/	Filter/search
?	Help

Useful One-Liners

# Get all images running in a namespace
kubectl get pods -o jsonpath='{range .items[*]}{.spec.containers[*].image}{"\n"}{end}' | sort -u

# Get pods sorted by restart count
kubectl get pods --sort-by='.status.containerStatuses[0].restartCount'

# Get pods sorted by CPU usage
kubectl top pods --sort-by=cpu

# Get all pods not in Running state
kubectl get pods --field-selector=status.phase!=Running

# Copy file from pod
kubectl cp my-pod:/path/to/file ./local-file

# Copy file to pod
kubectl cp ./local-file my-pod:/path/to/file

# Watch events in real time
kubectl get events -w --sort-by='.lastTimestamp'