Using CheatSheets To Apply Best Practices

Kubectl Kubernetes CheatSheet

Kubectl Kubernetes CheatSheet

1.1 Common Commands

Name Command
Run curl test temporarily kubectl run --rm mytest --image=yauritux/busybox-curl -it
Run wget test temporarily kubectl run --rm mytest --image=busybox -it
Run nginx deployment with 2 replicas kubectl run my-nginx --image=nginx --replicas=2 --port=80
Set namespace preference kubectl config set-context $(kubectl config current-context) --namespace=<ns1>
List pods with nodes info kubectl get pod -o wide
List everything kubectl get all --all-namespaces
Get all services kubectl get service --all-namespaces
Show nodes with labels kubectl get nodes --show-labels
Validate yaml file with dry run kubectl create --dry-run --validate -f pod-dummy.yaml
Start a temporary pod for testing kubectl run --rm -i -t --image=alpine test-$RANDOM -- sh
kubectl run shell command kubectl exec -it mytest -- ls -l /etc/hosts
Get system conf via configmap kubectl -n kube-system get cm kubeadm-config -o yaml
Get deployment yaml kubectl -n denny-websites get deployment mysql -o yaml
Explain resource kubectl explain pods, kubectl explain svc
Watch pods kubectl get pods -n wordpress --watch
Query healthcheck endpoint curl -L http://127.0.0.1:10250/healthz
Open a bash terminal in a pod kubectl exec -it storage sh
Check pod environment variables kubectl exec redis-master-ft9ex env
Enable kubectl shell autocompletion echo "source <(kubectl completion bash)" >>~/.bashrc, and reload
Use minikube dockerd in your laptop eval $(minikube docker-env), No need to push docker hub any more
Kubectl apply a folder of yaml files kubectl apply -R -f .
Get services sorted by name kubectl get services –sort-by=.metadata.name
Get pods sorted by restart count kubectl get pods –sort-by=’.status.containerStatuses[0].restartCount’
List all container images list-all-images.sh
Reference GitHub: kubernetes releases
Reference minikube cheatsheet, docker cheatsheet, OpenShift CheatSheet

1.2 Check Performance

Name Command
Get node resource usage kubectl top node
Get pod resource usage kubectl top pod
Get resource usage for a given pod kubectl top <podname> --containers
List resource utilization for all containers kubectl top pod --all-namespaces --containers=true

1.3 Resources Deletion

Name Command
Delete pod kubectl delete pod/<pod-name> -n <my-namespace>
Delete pod by force kubectl delete pod/<pod-name> --grace-period=0 --force
Delete pods by labels kubectl delete pod -l env=test
Delete deployments by labels kubectl delete deployment -l app=wordpress
Delete all resources filtered by labels kubectl delete pods,services -l name=myLabel
Delete resources under a namespace kubectl -n my-ns delete po,svc --all
Delete persist volumes by labels kubectl delete pvc -l app=wordpress
Delete statefulset only (not pods) kubectl delete sts/<stateful_set_name> --cascade=false

1.4 Log & Conf Files

Name Comment
Config folder /etc/kubernetes/
Certificate files /etc/kubernetes/pki/
Credentials to API server /etc/kubernetes/kubelet.conf
Superuser credentials /etc/kubernetes/admin.conf
kubectl config file ~/.kube/config
Kubernets working dir /var/lib/kubelet/
Docker working dir /var/lib/docker/, /var/log/containers/
Etcd working dir /var/lib/etcd/
Network cni /etc/cni/net.d/
Log files /var/log/pods/
log in master node /var/log/kube-apiserver.log, kube-scheduler.log, kube-controller-manager.log
log in worker node /var/log/kubelet.log, kubelet-proxy.log
Env /etc/systemd/system/kubelet.service.d/10-kubeadm.conf
Env export KUBECONFIG=/etc/kubernetes/admin.conf

1.5 Pod

Name Command
List all pods kubectl get pods
List pods for all namespace kubectl get pods -all-namespaces
List all critical pods kubectl get -n kube-system pods -a
List pods with more info kubectl get pod -o wide, kubectl get pod/<pod-name> -o yaml
Get pod info kubectl describe pod/srv-mysql-server
List all pods with labels kubectl get pods --show-labels
List running pods kubectl get pods –field-selector=status.phase=Running
Get Pod initContainer status kubectl get pod --template '{{.status.initContainerStatuses}}' <pod-name>
kubectl run command kubectl exec -it -n “$ns” “$podname” – sh -c “echo $msg >>/dev/err.log”
Watch pods kubectl get pods -n wordpress --watch
Get pod by selector podname=$(kubectl get pods -n $namespace –selector=”app=syslog” -o jsonpath='{.items[*].metadata.name}’)
List pods and containers kubectl get pods -o=’custom-columns=PODS:.metadata.name,CONTAINERS:.spec.containers[*].name’
List pods, containers and images kubectl get pods -o=’custom-columns=PODS:.metadata.name,CONTAINERS:.spec.containers[*].name,Images:.spec.containers[*].image’
Kubernetes Yaml Examples Link: kubernetes yaml templates

1.6 Label & Annontation

Name Command
Filter pods by label kubectl get pods -l owner=denny
Manually add label to a pod kubectl label pods dummy-input owner=denny
Remove label kubectl label pods dummy-input owner-
Manually add annonation to a pod kubectl annotate pods dummy-input my-url=https://dennyzhang.com

1.7 Deployment & Scale

Name Command
Scale out kubectl scale --replicas=3 deployment/nginx-app
online rolling upgrade kubectl rollout app-v1 app-v2 --image=img:v2
Roll backup kubectl rollout app-v1 app-v2 --rollback
List rollout kubectl get rs
Check update status kubectl rollout status deployment/nginx-app
Check update history kubectl rollout history deployment/nginx-app
Pause/Resume kubectl rollout pause deployment/nginx-deployment, resume
Rollback to previous version kubectl rollout undo deployment/nginx-deployment
Kubernetes Yaml Examples Link: kubernetes yaml templates, Link: Pausing and Resuming a Deployment

1.8 Quota & Limits & Resource

Name Command
Customize resource definition kubectl set resources deployment nginx -c=nginx --limits=cpu=200m,memory=512Mi
List Resource Quota kubectl get resourcequota
List Limit Range kubectl get limitrange
Customize resource definition kubectl set resources deployment nginx -c=nginx --limits=cpu=200m,memory=512Mi
Kubernetes Yaml Examples Link: kubernetes yaml templates

1.9 Service

Name Command
List all services kubectl get services
List service endpoints kubectl get endpoints
Get service detail kubectl get service nginx-service -o yaml
Get service cluster ip kubectl get service nginx-service -o go-template='{{.spec.clusterIP}}’
Get service cluster port kubectl get service nginx-service -o go-template='{{(index .spec.ports 0).port}}’
Expose deployment as lb service kubectl expose deployment/my-app --type=LoadBalancer --name=my-service
Expose service as lb service kubectl expose service/wordpress-1-svc --type=LoadBalancer --name=wordpress-lb
Kubernetes Yaml Examples Link: kubernetes yaml templates

1.10 Secrets

Name Command
List secrets kubectl get secrets --all-namespaces
Create secret from cfg file kubectl create secret generic db-user-pass --from-file./username.txt=
Generate secret echo -n 'mypasswd', then redirect to base64 -decode
Kubernetes Yaml Examples Link: kubernetes yaml templates

1.11 StatefulSet

Name Command
List statefulset kubectl get sts
Delete statefulset only (not pods) kubectl delete sts/<stateful_set_name> --cascade=false
Scale statefulset kubectl scale sts/<stateful_set_name> --replicas=5
Kubernetes Yaml Examples Link: kubernetes yaml templates

1.12 Volumes & Volume Claims

Name Command
List storage class kubectl get storageclass
Check the mounted volumes kubectl exec storage ls /data
Check persist volume kubectl describe pv/pv0001
Copy local file to pod kubectl cp /tmp/my <some-namespace>/<some-pod>:/tmp/server
Copy pod file to local kubectl cp <some-namespace>/<some-pod>:/tmp/server /tmp/my
Kubernetes Yaml Examples Link: kubernetes yaml templates

1.13 Events & Metrics

Name Command
View all events kubectl get events --all-namespaces
List Events sorted by timestamp kubectl get events –sort-by=.metadata.creationTimestamp

1.14 Node Maintenance

Name Command
Mark node as unschedulable kubectl cordon $NDOE_NAME
Mark node as schedulable kubectl uncordon $NDOE_NAME
Drain node in preparation for maintenance kubectl drain $NODE_NAME

1.15 Namespace & Security

Name Command
List authenticated contexts kubectl config get-contexts, ~/.kube/config
Load context from config file kubectl get cs --kubeconfig kube_config.yml
Switch context kubectl config use-context <cluster-name>
Delete the specified context kubectl config delete-context <cluster-name>
List all namespaces defined kubectl get namespaces
Set namespace preference kubectl config set-context $(kubectl config current-context) --namespace=<ns1>
List certificates kubectl get csr
Kubernetes Yaml Examples Link: kubernetes yaml templates

1.16 Network

Name Command
Temporarily add a port-forwarding kubectl port-forward redis-izl09 6379
Add port-forwaring for deployment kubectl port-forward deployment/redis-master 6379:6379
Add port-forwaring for replicaset kubectl port-forward rs/redis-master 6379:6379
Add port-forwaring for service kubectl port-forward svc/redis-master 6379:6379
Get network policy kubectl get NetworkPolicy

1.17 Patch

Name Summary
Patch service to loadbalancer kubectl patch svc "$APP_INSTANCE_NAME-grafana" -p '{"spec": {"type": "LoadBalancer"}}'

1.18 Extenstions

Name Summary
List api group kubectl api-versions
List all CRD kubectl get crd
List storageclass kubectl get storageclass
List all supported resources kubectl api-resources

1.19 Components & Services

1.19.1 Services on Master Nodes

Name Summary
kube-apiserver exposes the Kubernetes API from master nodes
etcd reliable data store for all k8s cluster data
kube-scheduler schedule pods to run on selected nodes
kube-controller-manager node controller, replication controller, endpoints controller, and service account & token controllers

1.19.2 Services on Worker Nodes

Name Summary
kubelet makes sure that containers are running in a pod
kube-proxy perform connection forwarding
Container Runtime Kubernetes supported runtimes: Docker, rkt, runc and any OCI runtime-spec implementation.

1.19.3 Addons: pods and services that implement cluster features

Name Summary
DNS serves DNS records for Kubernetes services
Web UI a general purpose, web-based UI for Kubernetes clusters
Container Resource Monitoring collect, store and serve container metrics
Cluster-level Logging save container logs to a central log store with search/browsing interface

1.19.4 Tools

Name Summary
kubectl the command line util to talk to k8s cluster
kubeadm the command to bootstrap the cluster
kubefed the command line to control a Kubernetes Cluster Federation
Kubernetes Components Link: Kubernetes Components


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