Kubectl

wikipedia:kubectl is a command line interface for running commands against Kubernetes clusters.

Installation

• To install in macOS execute: brew install kubernetes-cli
• Kubectl in Amazon Linux
• Ubuntu Kubernetes installation:
  • snap install kubectl --classic
  • curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
  • chmod +x kubectl; mv kubectl /bin/
• ~/.kube/config
• scoop install kubectl

Commands

• kubectl --help
• kubectl api-versions
• kubectl apply
• kubectl auth
• kubectl create
• kubectl completion
• kubectl config: config-use-context
• kubectl cp
• kubectl debug (since v1.18, March 2020)
• kubectl delete
• kubectl describe
• kubectl diff (since v1.18, March 2020)
• kubectl edit
• kubectl explain
• kubectl expose
• kubectl exec
• kubectl get all | nodes | pvc | pods | replicaset .../...
• kubectl label
• kubectl logs
• kubectl patch
• kubectl port-forward
• kubectl proxy
• kubectl plugin
• kubectl replace
• kubectl rolling-update
• kubectl rollout
• kubectl set
• kubectl top
• kubectl virt

Kubectl information commands

• kubectl cluster-info: dump
• kubectl config view
• kubectl get pods: kubectl get pods -n kube-system
• kubectl top pod PODNAME
• kubectl describe
• kubectl get namespaces
• kubectl get nodes
• kubectl get services
• kubectl get configmaps
• kubectl logs
• kubectl version

kubectl operation commands

• kubectl create
• kubectl delete pod
• kubectl delete namespace MY_NAMESPACE
• Connect to a Pod: kubectl exec -it YOUR_POD_NANE -- /bin/bash

kubectl command reference

The following table includes short descriptions and the general syntax for all of the kubectl operations:

• Apply kubectl apply -f FILENAME [flags]. Apply a configuration change to a resource from a file or stdin. Allows to create a Pod.

• Attach kubectl attach POD -c CONTAINER [-i] [-t] [flags]:Attach to a running container either to view the output stream or interact with the container (stdin)

• Auto Scale kubectl autoscale (-f FILENAME \| TYPE NAME \| TYPE/NAME) [--min=MINPODS] --max=MAXPODS [--cpu-percent=CPU] [flags]: Automatically scale the set of pods that are managed by a replication controller

• Cluster Info kubectl cluster-info [flags] :Display endpoint information about the master and services in the cluster

• Create kubectl create -f FILENAME [flags]: Create one or more resources from a file or stdin
  • kubectl create namespace myexamplenamespace
  • kubectl create sa my_new_user (Create service account for your my_new_user)
  • kubectl create -f mypod.yaml

• Config: kubectl config .../...
  • kubectl config view

• Delete kubectl delete (-f FILENAME \| TYPE [NAME \| /NAME \| -l label \| --all]) [flags] :Delete resources
  • kubectl delete --all namespaces

• Describe kubectl describe (-f FILENAME \| TYPE [NAME_PREFIX \| /NAME \| -l label]) [flags] : Detailed state of one or more resources.
  • kubectl describe pod MyPodName
  • kubectl describe pods
  • kubectl describe replicaset MyReplicaName

• Edit kubectl edit (-f FILENAME \| TYPE NAME \| TYPE/NAME) [flags] : Edit and update the definition of one or more resources on the server by using the default editor.

• Execute kubectl exec POD [-c CONTAINER] [-i] [-t] [flags] [-- COMMAND [args...]]: Execute a command against a container in a pod

• Logs kubectl logs POD [-c CONTAINER] [--follow] [flags]: Print the logs for a container in a pod.
  • kubectl logs -l app=elasticsearch (using labels: -l)

• Get:

• Replace: kubectl replace --force -f yml_file_describing_pod.yml

• Proxy: kubectl proxy --port=8080

• Rolling-update: kubectl rolling-update

• Run kubectl run NAME --image=image [--env="key=value"] [--port=port] [--replicas=replicas] [--dry-run=bool] [--overrides=inline-json] [flags]: Run a specified image on the cluster.

• Scale: kubectl scale deployment YOUR_DEPLOYMENT_NAME

• Stop kubectl stop

• Version kubectl version [--client] [flags]: Display the Kubernetes version running on the client and server.

Activities

• Create and configure a basic Pod (kubectl apply)
• Read official kubectl cheat sheet: https://kubernetes.io/docs/reference/kubectl/cheatsheet/
• Check examples: https://www.codegrepper.com/code-examples/shell/kubectl+describe+ingress+output+yaml
• https://stackoverflow.com/questions/tagged/kubectl?tab=Votes
• Kubernetes quiz
• Merge multiple kubeconfigs: ~/.kube/configs into one using kubectl konfig merge

Related

• Krew
• kops
• Kots kubectl plugin
• K9s
• aws eks --region $(terraform output -raw region) update-kubeconfig --name $(terraform output -raw cluster_name)
• kubectl-convert
• kubeadm
• Error: flags cannot be place before plugin name
• kubectl.kubernetes.io
• kubectl (alias)

See also

• Kubernetes Components, kube-proxy, kube-scheduler, kube-apiserver, kubelet, kubectl, kubeadm, Kubernetes controller manager, Kubernetes controllers, Kubernetes Addons, Kubernetes Topology Manager
• kubectl: [ cp | config | create | delete | edit | explain | apply | exec | get | set | drain | uncordon | rolling-update | rollout | logs | run | auth | label | annotate | version | top | diff | debug | replace | describe | port-forward | proxy | scale | rollout | api-resources | expose deployment | expose | patch | attach | get endpoints | ~/.kube/config | kubectl logs --help | kubectl --help, kubectl-convert, kubectl autoscale, kubectl.kubernetes.io

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Source: https://en.wikiversity.org/wiki/DevOps/Kubernetes/kubectl