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
List everything kubectl get all --all-namespaces
List pods with nodes info kubectl get pod -o wide
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
kubectl run instance with replicas kubectl run my-nginx --image=nginx --replicas=2 --port=80
Explain resource kubectl explain pods, kubectl explain svc
Get all services kubectl get service --all-namespaces
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
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’
Reference minikube cheatsheet, docker 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 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

1.11 Volumes & Volume Claims

Name Command
Check the mounted volumes kubectl exec storage ls /data
Check persist volume kubectl describe pv/pv0001
List storage class kubectl get storageclass
Copy files kubectl cp /tmp/foo <namespace1>/<pod1>:/tmp/bar
Kubernetes Yaml Examples Link: kubernetes yaml templates

1.12 Events & Metrics

Name Command
View all events kubectl get events --all-namespaces

1.13 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

1.14 Namespace & Security

Name Command
List authenticated contexts kubectl config get-contexts
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
List certificates kubectl get csr
Kubernetes Yaml Examples Link: kubernetes yaml templates

1.15 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

1.16 Extenstions

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

1.17 Components & Services

1.17.1 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

1.17.2 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.

1.17.3 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

1.17.4 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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