The Kubernetes command-line tool, kubectl, allows you to run commands against Kubernetes clusters. You can use kubectl to deploy applications, inspect and manage cluster resources, and view logs. For more information including a complete list of kubectl operations, see the kubectl reference documentation.
The kubectl command line tool lets you control Kubernetes clusters. For configuration, kubectl looks for a file named config in the $HOME/.kube directory. You can specify other kubeconfig files by setting the KUBECONFIG environment variable or by setting the --kubeconfig flag.
This overview covers kubectl syntax, describes the command operations, and provides common examples. For details about each command, including all the supported flags and subcommands, see the kubectl reference documentation. For installation instructions see installing kubectl.
Use the following syntax to run kubectl commands from your terminal window:
kubectl [command] [TYPE] [NAME] [flags]
-
command: Specifies the operation that you want to perform on one or more resources, for example create, get, describe, delete.
-
TYPE: Specifies the resource type. Resource types are case-insensitive and you can specify the singular, plural, or abbreviated forms. For example, the following commands produce the same output:
-
NAME: Specifies the name of the resource. Names are case-sensitive. If the name is omitted, details for all resources are displayed, for example kubectl get pods.
-
flags: Specifies optional flags. For example, you can use the -s or --server flags to specify the address and port of the Kubernetes API server.
kubectl completion bash > /etc/bash_completion.d/kubectlkubectl config current-context
kubectl config view
kubectl config set-context dev --namespace=development \
--cluster=lithe-cocoa-92103_kubernetes \
--user=lithe-cocoa-92103_kubernetes
kubectl config use-context dev
kubectl config view --kubeconfig my-kube-config
kubectl config --kubeconfig=/root/my-kube-config use-context researchkubectl proxykubectl get all --all-namespaceskubectl get node
kubectl edit node msater
kubectl get nodes --show-labels
kubectl drain <node name>
kubectl uncordon <node name>
kubectl drain node01 --ignore-daemonsets
kubectl describe node master
kubectl cordon node03kubectl taint nodes <node-name> key=value:taint-effect
kubectl taint nodes node1 app=blue:NoSchedulekubectl logs -f event-simulator-pod
kubectl logs -f <pod-name> <container-name>
kubectl logs -f even-simulator-pod event-simulatorkubectl get pods -n kube-system
kubectl get pods -o wide
kubectl get pods -l app=snowflake -n=development
kubectl run nginx --image=nginx --namespace=<insert-namespace-name-here>
kubectl get pods --namespace=<insert-namespace-name-here>
kubectl get pods --selector env=dev
kubectl get all --selector env=prod,bu=finance,tier=frontend
kubectl logs my-custom-scheduler -n kube-systemkubectl get services
kubectl describe servicekubectl create ns test
kubectl create namespace dev
kubectl get pods --namespace=test
kubectl run redis --image=redis --namespace=test
kubectl get pods --all-namespaces
kubectl create -f pod-definition.yaml --namespace=dev
kubectl get namespaceskubectl run httpd --image=httpd:alpine --port=80 --expose
kubectl run nginx-pod --image=nginx:alpine
kubectl run redis --image=redis:alpine -l tier=db
kubectl run custom-nginx --image=nginx --port=8080
kubectl run httpd --image=httpd:alpine --port=80 --expose
kubectl get pods --selector app=App1kubectl expose pod redis --port=6379 --name redis-servicekubectl get secrets
kubectl describe secret
kubectl create secret generic db-secret --from-literal=DB_Host=sql01 --from-literal=DB_User=root --from-literal=DB_Password=password123kubectl create deployment webapp --image=kodekloud/webapp-color
kubectl get deployment
kubectl get replicaset
kubectl get rs
kubectl describe deployment
kubectl create deployment httpd-frontend --image=httpd:2.4-alpine
kubectl scale deplyoment httpd-frontend --replicas=3
kubectl edit deployment.v1.apps/nginx-deployment
kubectl rollout status deployment/nginx-deployment
kubectl rollout undo deployment.v1.apps/nginx-deployment
kubectl scale deployment.v1.apps/nginx-deployment --replicas=10
kubectl set image deployment.v1.apps/nginx-deployment nginx=nginx:sometag
kubectl scale deployment blue --replicas=6
kubectl scale deployment.v1.apps/nginx-deployment --replicas=10
kubectl autoscale deployment.v1.apps/nginx-deployment --min=10 --max=15 --cpu-percent=80kubectl rollout status deployment/myapp-deployment
kubectl rollout history deployment/myapp-deployment
kubectl rollout undo deployment/myapp-deploymentkubectl get networkpolicy
kubectl describe networkpolicykubectl get daemonsets --all-namespaces
kubectl describe daemonset kube-proxy --namespace=kube-system
kubectl describe daemonset kube-flannel-ds-amd64 --namespace=kube-systemkubectl label node ubuntu owner=alpin # add label
kubectl label node ubuntu owner- # remove labelkubectl scale deployment/webapp --replicas=3
# You can also use kubectl scale deployment or kubectl edit deployment to change the number of replicas once the object has been created.
kubectl edit deployment redis-deploy
kubectl scale deployment/redis-deploy --replicas=2 --namespace=dev-nskubectl create configmap app-config --from-literal=APP_COLOR=blue --from-literal=APP_MODE=prod
kubectl create configmap app-config --from-file=app_config.properties (Another way)kubectl set image deployment/myapp-deployment nginx=nginx:1.9.1kubectl get clusterroles --no-headers | wc -l (or)
kubectl get clusterroles --no-headers -o json | jq '.items | length'
kubectl get clusterrolebindings --no-headers | wc -l (or)
kubectl get clusterrolebindings --no-headers -o json | jq '.items | length'
kubectl describe clusterrolebinding cluster-adminkubectl auth can-i create deployments
kubectl auth can-i delete nodes
kubectl auth can-i create deployments --as dev-user
kubectl auth can-i create pods --as dev-user
kubectl auth can-i create pods --as dev-user --namespace testkubectl get roles
kubectl get rolebindings
kubectl describe role developer
kubectl describe rolebinding devuser-developer-bindingkubectl run --restart=Never --image=busybox static-busybox --dry-run=client -o yaml --command -- sleep 1000 > /etc/kubernetes/manifests/static-busybox.yaml# Step 1: Create the deployment YAML file
kubectl create deployment redis-deploy --image redis --namespace=dev-ns --dry-run=client -o yaml > deploy.yaml
kubectl create -f deploy.yaml
# Step 2: Edit the YAML file and add update the replicas to 2.
#Step 3: Run kubectl apply -f deploy.yaml to create the deployment in the dev-ns namespace.
kubectl apply -f deploy.yaml
# check certificate commands
```bash
openssl x509 -in /etc/kubernetes/pki/ca.crt -text
openssl x509 -in /etc/kubernetes/pki/apiserver.crt -text
openssl x509 -in /etc/kubernetes/pki/etcd/server.crt -textkubectl label nodes <node-name> <label-key>=<label-value>Example
kubectl label nodes minikube foo=bar
kubectl get nodes -o jsonpath='{.items[*].status.addresses[?(@.type=="InternalIP")].address}' > /root/CKA/node_ips
kubectl get nodes -o=jsonpath='{.items[*].metadata.name}'
kubectl get nodes -o jsonpath='{.items[*].status.nodeInfo.osImage}'kubectl drain <NODE_NAME> --ignore-daemonsets --delete-local-data