Kubectl

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

Installation

• To install in MacOS execute: brew install kubernetes-cli
• Ubuntu Kubernetes installation: snap install kubectl --classic

Commands

• kubectl apply
• kubectl auth
• kubectl create
• kubectl config
• kubectl debug (since v1.18, March 2020)
• kubectl delete
• kubectl describe
• kubectl diff (since v1.18, March 2020)
• kubectl edit
• kubectl expose
• kubectl exec
• kubectl get nodes|pods|replicaset .../...
• kubectl label
• kubectl logs
• kubectl replace
• kubectl rolling-update
• kubectl rollout

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/

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
• Kubernetes: distributions, tools, CKA, CKS, Kubernetes interfaces: CSI, CNI, installation, workloads, networking, kubeadm, Kubernetes API, Kubernetes API Server, kubectl, kubeadm, kubelet, kube-proxy, Cloud services: EKS, GKE, TKE, DKS, Helm, Kubernetes RBAC, Kubernetes deployments, Minikube, Rancher, OpenShift, Charmed Kubernetes, Ingress, Kubernetes scheduler, Kubernetes Finalizers, logging, Kubernetes operator, Orka, kind:, Kubernetes namespaces, Kubernetes dashboard, Kubernetes Metrics Server, Field Selectors, CoreDNS, CRI, Kubernetes Topology Manager, Kubernetes governance: (SIG, KEP), Kustomize, controllers, ReadinessProbe, LivenessProbe, KOPS, K9s, Kui, k3s, ImagePullBackOff, PDB, EndPoints, Kots, metadata, Karpenter, Replicated.com, Kubernetes Authenticating, Kubernetes timeline, Changelog/Versions, service accounts, Kubernetes Pod Lifecycle, Kubernetes Conformance Certified, Kubernetes backup, Kubernetes Pod Security Admission, tEKS, Kubernetes events, Kubernetes ports, Kubernetes policies, Connect, addons, DoKC, Kubernetes control plane, Kubernetes Federation, Kubernetes info, Kubetest2, Sidecar (Kubernetes)

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