📖 Kubernetes CheatSheets In A4
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1 Kubernets CheatSheet


PRs Welcome

File me Issues or star this repo.

See more CheatSheets from Denny: #denny-cheatsheets

1.0.1 Common Commands

List everythingkubectl get all --all-namespaces
Validate yaml file with dry runkubectl create --dry-run --validate -f pod-dummy.yaml
Start a temporary pod for testingkubectl run --rm -i -t --image=alpine test-$RANDOM -- sh
Run wget test temporarilykubectl run --rm mytest --image=busybox -it
Run curl test temporarilykubectl run --rm mytest --image=yauritux/busybox-curl -it
Get system conf via configmapkubectl -n kube-system get cm kubeadm-config -o yaml
Explain resourcekubectl explain pods, kubectl explain svc
Get all serviceskubectl get service --all-namespaces
Get services sorted by namekubectl get services –sort-by=.metadata.name
Get pods sorted by restart countkubectl get pods –sort-by=’.status.containerStatuses[0].restartCount’
Query healthcheck endpointcurl -L
Open a bash terminal in a podkubectl exec -it storage sh
Check pod environment variableskubectl exec redis-master-ft9ex env
Enabling shell autocompletion for kubectlecho "source <(kubectl completion bash)" >> ~/.bashrc, then reconnect
In mac desktop, use minikube dockerdeval $(minikube docker-env), No need to docker push any more

1.1 Components & Services

  • Services on Master Nodes
kube-apiserverexposes the Kubernetes API from master nodes
etcdreliable data store for all k8s cluster data
kube-schedulerschedule pods to run on selected nodes
kube-controller-managernode controller, replication controller, endpoints controller, and service account & token controllers
  • Services on Worker Nodes
kubeletmakes sure that containers are running in a pod
kube-proxyperform connection forwarding
Container RuntimeKubernetes supported runtimes: Docker, rkt, runc and any OCI runtime-spec implementation.
  • Addons: pods and services that implement cluster features
DNSserves DNS records for Kubernetes services
Web UIa general purpose, web-based UI for Kubernetes clusters
Container Resource Monitoringcollect, store and serve container metrics
Cluster-level Loggingsave container logs to a central log store with search/browsing interface
  • Tools
kubectlthe command line util to talk to k8s cluster
kubeadmthe command to bootstrap the cluster
kubefedthe command line to control a Kubernetes Cluster Federation
Kubernetes Componentslink: Kubernetes Components

1.2 Check Performance

Get node resource usagekubectl top node
Get pod resource usagekubectl top pod
Get resource usage for a given podkubectl top <podname> --containers
List resource utilization for all containerskubectl top pod --all-namespaces --containers=true

1.3 Resources Deletion

Delete podkubectl delete pod hello-node-95913-n63qs -n $my-namespace
Delete pods by labelskubectl delete pod -l env=test
Delete deployments by labelskubectl delete deployment -l app=wordpress
Delete persist volumes by labelskubectl delete pvc -l app=wordpress
Delete statefulset only (not pods)kubectl delete sts <stateful_set_name> --cascade=false

1.4 Pod

List all podskubectl get pods
List pods for all namespacekubectl get pods -all-namespaces
List all critical podskubectl get -n kube-system pods -a
List pods with more infokubectl get pod -o wide, kubectl get pod -o yaml
Get pod infokubectl describe pod srv-mysql-server
List all pods with labelskubectl get pods --show-labels
Get Pod initContainer statuskubectl get pod --template '{{.status.initContainerStatuses}}' <pod-name>
kubectl run commandkubectl exec -it -n “$ns” “$podname” – sh -c “echo $msg >>/dev/err.log”
Get pod by selectorpodname=$(kubectl get pods -n $namespace –selector=”app=syslog” -o jsonpath=’{.items[*].metadata.name}’)
List pods with docker imageskubectl get pods -o=jsonpath=’{range .items[*]}{.metadata.name}:{.spec.containers[0].name}{“\t”}{.spec.containers[0].image}{“\n”}{end}’
Kubernetes Yaml Exampleslink: kubernetes yaml templates

1.5 Label & Annontation

Filter pods by labelkubectl get pods -l owner=denny
Manually add label to a podkubectl label pods dummy-input owner=denny
Remove labelkubectl label pods dummy-input owner-
Manually add annonation to a podkubectl annotate pods dummy-input my-url=https://www.dennyzhang.com

1.6 Deployment & Scale

link: Pausing and Resuming a Deployment

Scale outkubectl scale --replicas=3 deployment/nginx-app
online rolling upgradekubectl rollout app-v1 app-v2 --image=img:v2
Roll backupkubectl rollout app-v1 app-v2 --rollback
List rolloutkubectl get rs
Check update statuskubectl rollout status deployment/nginx-app
Check update historykubectl rollout history deployment/nginx-app
Pause/Resumekubectl rollout pause deployment/nginx-deployment, resume
Rollback to previous versionkubectl rollout undo deployment/nginx-deployment
Kubernetes Yaml Exampleslink: kubernetes yaml templates

1.7 Quota & Limits

List Resource Quotakubectl get resourcequota
List Limit Rangekubectl get limitrange
Kubernetes Yaml Exampleslink: kubernetes yaml templates

1.8 Service

List all serviceskubectl get services
List service endpointskubectl get endpoints
Get service detailkubectl get service nginx-service -o yaml
Get service cluster ipkubectl get service nginx-service -o go-template=’{{.spec.clusterIP}}’
Get service cluster portkubectl get service nginx-service -o go-template=’{{(index .spec.ports 0).port}}’
Kubernetes Yaml Exampleslink: kubernetes yaml templates

1.9 StatefulSet

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

1.10 Volumes & Volume Claims

Check the mounted volumeskubectl exec storage ls /data
Check persist volumekubectl describe pv pv0001
List storage classkubectl get storageclass
Kubernetes Yaml Exampleslink: kubernetes yaml templates

1.11 Security

List certificateskubectl get csr
Kubernetes Yaml Exampleslink: kubernetes yaml templates

1.12 Resources

Customize resource definitionkubectl set resources deployment nginx -c=nginx --limits=cpu=200m,memory=512Mi

1.13 Other Components

1.13.1 Log files

API Server.log= in master node/var.log=/kube-apiserver.log
Scheduler.log= in master node/var.log=/kube-scheduler.log
Controller.log= in master node/var.log=/kube-controller-manager.log
Kubelet.log= in worker node/var.log=/kubelet.log
Kube Proxy.log= in worker node/var.log=/kubelet-proxy.log

1.13.2 Events & Metrics

View all eventskubectl get events --all-namespaces

1.13.3 Namespace & Security

List authenticated contextskubectl config get-contexts
List contextskubectl config get-contexts
Switch contextkubectl config use-context <cluster-name>
List all namespaces definedkubectl get namespaces
kubectl config file~/.kube/config
Kubernetes Yaml Exampleslink: kubernetes yaml templates

1.13.4 Network

Temporarily add a port-forwardingkubectl port-forward redis-izl09 6379
Add port-forwaring for deploymentkubectl port-forward deployment/redis-master 6379:6379
Add port-forwaring for replicasetkubectl port-forward rs/redis-master 6379:6379
Add port-forwaring for servicekubectl port-forward svc/redis-master 6379:6379
Get network policykubectl get NetworkPolicy

1.14 Basic

1.14.1 Key Concepts

CNCFCloud Native Computing Foundation
CRIContainer Runtime Interface
CNIContainer Network Interface
CSIContainer Storage Interface

1.14.2 Kubernets Critical Files

Config folder/etc/kubernetes/
Certificate files/etc/kubernetes/pki/
Credentials to API server/etc/kubernetes/kubelet.conf
Superuser credentials/etc/kubernetes/admin.conf
Kubernets working dir/var/lib/kubelet/
Docker working dir/var/lib/docker/
Etcd working dir/var/lib/etcd/
Network cni/etc/cni/net.d/
Docker container log/var/log/containers/
Log files/var/log/pods/
Envexport KUBECONFIG=/etc/kubernetes/admin.conf

1.14.3 Check status

List everythingkubectl get all --all-namespaces
Get cluster infokubectl cluster-info
Get configurationkubectl config view
Get kubectl versionkubectl version
Get component statuskubectl get componentstatus
Similar to docker pskubectl get nodes
Similar to docker inspectkubectl describe pod nginx-app-413181-cn
Similar to docker logskubectl logs
Similar to docker execkubectl exec
Get services for current namespacekubectl get svc
Get node statuskubectl describe node $node_name

1.14.4 Kubernetes Developer Resources

API Conventionslink: API Conventions

1.15 Minikube

Get minikube versionminikube version, link: all minikube releases
Start minikube with a specific k8s versionminikube start --kubernetes-version v1.10.0
Start minikube env with a bigger machine flavorminikube start --memory 5120 --cpus=4
Gets all available Kubernetes versions for minikubeminikube get-k8s-versions
Mount host OS’s folder to minikube VMminikube mount /host-mount-path:/vm-mount-path
Check minikube config in your host OS desktop~/.minikube/machines/minikube/config.json
folder of k8s.io/minikube-hostpath provisioner/tmp/hostpath-provisioner, /tmp/hostpath_pv
Critical minikube folder/var/lib/localkube, /var/lib/docker, /data
minikube docker-enveval $(minikube docker-env)
Get minikube logminikube logs
Get dashboardminikube dashboard
SSH to minikube vmminikube ssh
Get ipminikube ip
Get cluster infokubectl cluster-info
List addonsminikube addons list
Get service infominikube service $srv_name

1.16 Misc scripts

  • Tail pod log by label
kubectl get pod -l "$mylabel" -n "$namespace" | tail -n1 \
    | awk -F' ' '{print $1}' | xargs -I{} \
      kubectl logs -n "$namespace" -f {}
  • Get node hardware resource utilization
kubectl get nodes --no-headers \
     | awk '{print $1}' | xargs -I {} \
     sh -c 'echo {}; kubectl describe node {} | grep Allocated -A 5'

kubectl get nodes --no-headers | awk '{print $1}' | xargs -I {} \
    sh -c 'echo {}; kubectl describe node {} | grep Allocated -A 5 \
     | grep -ve Event -ve Allocated -ve percent -ve -- ; echo'
  • Apply the configuration in manifest.yaml and delete all the other configmaps that are not in the file.
kaubectl apply --prune -f manifest.yaml --all --prune-whitelist=core/v1/ConfigMap

1.17 More Resources

License: Code is licensed under MIT License.