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See more CheatSheets from Denny: #denny-cheatsheets
| Name | Command |
|---|
| List everything | kubectl get all --all-namespaces |
| 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 |
| Run wget test temporarily | kubectl run --rm mytest --image=busybox -it |
| Run curl test temporarily | kubectl run --rm mytest --image=yauritux/busybox-curl -it |
| Get system conf via configmap | kubectl -n kube-system get cm kubeadm-config -o yaml |
| Explain resource | kubectl explain pods, kubectl explain svc |
| Get all services | kubectl get service --all-namespaces |
| 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’ |
| 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 |
| Enabling shell autocompletion for kubectl | echo "source <(kubectl completion bash)" >> ~/.bashrc, then reconnect |
| In mac desktop, use minikube dockerd | eval $(minikube docker-env), No need to docker push any more |
1.1 Components & Services
| 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 |
| 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. |
- 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 |
| 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 |
| Name | Command |
|---|
| Delete pod | kubectl delete pod hello-node-95913-n63qs -n $my-namespace |
| Delete pods by labels | kubectl delete pod -l env=test |
| Delete deployments by labels | kubectl delete deployment -l app=wordpress |
| Delete persist volumes by labels | kubectl delete pvc -l app=wordpress |
| Delete statefulset only (not pods) | kubectl delete sts <stateful_set_name> --cascade=false |
| Name | Command |
|---|
| List all pods | kubectl get pods |
| List pods for all namespace | kubectl get pods -all-namespaces |
| List all critical pods | kubectl get -n kube-system pods -a |
| List pods with more info | kubectl get pod -o wide, kubectl get pod -o yaml |
| Get pod info | kubectl describe pod srv-mysql-server |
| List all pods with labels | kubectl get pods --show-labels |
| Get Pod initContainer status | kubectl get pod --template '{{.status.initContainerStatuses}}' <pod-name> |
| kubectl run command | kubectl exec -it -n “$ns” “$podname” – sh -c “echo $msg >>/dev/err.log” |
| Get pod by selector | podname=$(kubectl get pods -n $namespace –selector=”app=syslog” -o jsonpath=’{.items[*].metadata.name}’) |
| List pods with docker images | kubectl get pods -o=jsonpath=’{range .items[*]}{.metadata.name}:{.spec.containers[0].name}{“\t”}{.spec.containers[0].image}{“\n”}{end}’ |
| Kubernetes Yaml Examples | link: kubernetes yaml templates |
| 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://www.dennyzhang.com |
link: Pausing and Resuming a Deployment
| 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 |
| 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}}’ |
| Kubernetes Yaml Examples | link: kubernetes yaml templates |
| Name | Command |
|---|
| List statefulset | kubectl get sts |
| Scale statefulset | kubectl scale sts <stateful_set_name> --replicas=5 |
| Delete statefulset only (not pods) | kubectl delete sts <stateful_set_name> --cascade=false |
| Kubernetes Yaml Examples | link: kubernetes yaml templates |
1.10 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 |
| Kubernetes Yaml Examples | link: kubernetes yaml templates |
| Name | Command |
|---|
| Customize resource definition | kubectl set resources deployment nginx -c=nginx --limits=cpu=200m,memory=512Mi |
| Name | Command |
|---|
| 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 |
| Name | Command |
|---|
| View all events | kubectl get events --all-namespaces |
1.13.3 Namespace & Security
| Name | Command |
|---|
| List authenticated contexts | kubectl config get-contexts |
| List contexts | kubectl config get-contexts |
| Switch context | kubectl config use-context <cluster-name> |
| List all namespaces defined | kubectl get namespaces |
| kubectl config file | ~/.kube/config |
| Kubernetes Yaml Examples | link: kubernetes yaml templates |
| 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 |
| Name | Summary |
|---|
| CNCF | Cloud Native Computing Foundation |
| CRI | Container Runtime Interface |
| CNI | Container Network Interface |
| CSI | Container Storage Interface |
1.14.2 Kubernets Critical 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 |
| 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/ |
| Env | export KUBECONFIG=/etc/kubernetes/admin.conf |
| Env | /etc/systemd/system/kubelet.service.d/10-kubeadm.conf |
| Name | Summary |
|---|
| List everything | kubectl get all --all-namespaces |
| Get cluster info | kubectl cluster-info |
| Get configuration | kubectl config view |
| Get kubectl version | kubectl version |
| Get component status | kubectl get componentstatus |
Similar to docker ps | kubectl get nodes |
Similar to docker inspect | kubectl describe pod nginx-app-413181-cn |
Similar to docker logs | kubectl logs |
Similar to docker exec | kubectl exec |
| Get services for current namespace | kubectl get svc |
| Get node status | kubectl describe node $node_name |
1.14.4 Kubernetes Developer Resources
| Name | Command |
|---|
| Get minikube version | minikube version, link: all minikube releases |
| Start minikube with a specific k8s version | minikube start --kubernetes-version v1.10.0 |
| Start minikube env with a bigger machine flavor | minikube start --memory 5120 --cpus=4 |
| Gets all available Kubernetes versions for minikube | minikube get-k8s-versions |
| Mount host OS’s folder to minikube VM | minikube 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-env | eval $(minikube docker-env) |
| Get minikube log | minikube logs |
| Get dashboard | minikube dashboard |
| SSH to minikube vm | minikube ssh |
| Get ip | minikube ip |
| Get cluster info | kubectl cluster-info |
| List addons | minikube addons list |
| Get service info | minikube service $srv_name |
namespace="mynamespace"
mylabel="app=mylabel"
kubectl get pod -l "$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
License: Code is licensed under MIT License.
https://kubernetes.io/docs/reference/kubectl/cheatsheet/
https://github.com/kubecamp/kubernetes_in_2_days
https://marc.xn–wckerlin-0za.ch/computer/kubernetes-on-ubuntu-16-04
https://codefresh.io/kubernetes-guides/kubernetes-cheat-sheet/
