Kubectl Cheatsheet

Kubectl

Kubectl is a command line tool for communicating with a Kubernetes ([[kubernetes]]) cluster's control pane, using the Kubernetes API.

Documentation: Kubectl Reference

Installation

On Windows (PowerShell)

Install Kubectl with Chocolatey ([[chocolatey]]):

choco install kubernetes-cli

On Linux

[!INFO] Installing on WSL2 On WSL2 it's recommended to install Docker Desktop [[docker-desktop]], which automatically comes with kubectl.

Download the latest release

1curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"

Install Kubectl

1sudo install -o root -g root -m 0755 kubectl /usr/local/bin/kubectl

On mac OS

Install Kubectl with Homebrew ([[homebrew]]):

1brew install kubernetes-cli

Config Management

Multiple Config Files

On Windows (PowerShell

1$env:KUBECONFIG = "$HOME/.kube/prod-k8s-clcreative-kubeconfig.yaml;$HOME/.kube/infra-home-kube-prod-1.yml;$HOME/.kube/infra-home-kube-demo-1.yml;$HOME/.kube/infra-cloud-kube-prod-1.yml"

On Linux

1export KUBECONFIG=~/.kube/kube-config-1.yml:~/.kube/ube-config-2.yml

Commands

Networking

Connect containers using Kubernetes internal DNS system: <service-name>.<namespace>.svc.cluster.local

Troubleshoot Networking with a netshoot toolkit Container: kubectl run tmp-shell --rm -i --tty --image nicolaka/netshoot -- /bin/bash

Containers

Restart Deployments (Stops and Restarts all Pods): kubectl scale deploy <deployment> --replicas=0 kubectl scale deploy <deployment> --replicas=1

Executing Commands on Pods: kubectl exec -it <PODNAME> -- <COMMAND> kubectl exec -it generic-pod -- /bin/bash

Config and Cluster Management

COMMAND	DESCRIPTION
`kubectl cluster-info`	Display endpoint information about the master and services in the cluster
`kubectl config view`	Get the configuration of the cluster

Resource Management

COMMAND	DESCRIPTION
`kubectl get all --all-namespaces`	List all resources in the entire Cluster
`kubectl delete <RESOURCE> <RESOURCENAME> --grace-period=0 --force`	Try to force the deletion of the resource

List of Kubernetes Resources "Short Names"

Short Name	Long Name
`csr`	`certificatesigningrequests`
`cs`	`componentstatuses`
`cm`	`configmaps`
`ds`	`daemonsets`
`deploy`	`deployments`
`ep`	`endpoints`
`ev`	`events`
`hpa`	`horizontalpodautoscalers`
`ing`	`ingresses`
`limits`	`limitranges`
`ns`	`namespaces`
`no`	`nodes`
`pvc`	`persistentvolumeclaims`
`pv`	`persistentvolumes`
`po`	`pods`
`pdb`	`poddisruptionbudgets`
`psp`	`podsecuritypolicies`
`rs`	`replicasets`
`rc`	`replicationcontrollers`
`quota`	`resourcequotas`
`sa`	`serviceaccounts`
`svc`	`services`

陼 Logs and Troubleshooting

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Logs

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MySQL

kubectl run -it --rm --image=mysql:5.7 --restart=Never mysql-client -- mysql -u USERNAME -h HOSTNAME -p

Networking

kubectl run -it --rm --image=nicolaka/netshoot netshoot -- /bin/bash

Resources stuck in Terminating state

...

Namespaces

Save the namespace in a YOUR-NAMESPACE.json file.

kubectl get ns YOUR-NAMESPACE -o json > YOUR-NAMESPACE.json

Edit the YOUR-NAMESPACE.json and remove the section in Finalizers.
Update the NAMESPACE.

kubectl replace --raw "/api/v1/namespaces/YOUR-NAMESPACE/finalize" -f .\YOUR-NAMESACE.json