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    Kubectl

    🛠️ Kubectl Cheat-Sheet

    Kubectl is the command line tool to interact with a Kubernetes Cluster's control plane using the Kubernetes API.

    ⚙️ Installation

    📦 On Windows (PowerShell)

    Install kubectl using chocolatey:

    choco install kubernetes-cli

    📥 On Linux

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

    Download the Latest Release

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

    Install kubectl

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

    🍏 On macOS

    Install kubectl using homebrew:

    brew install kubernetes-cli

    ⚙️ Config Management

    📂 Multiple Config Files

    On Windows (PowerShell)

    $env:KUBECONFIG = "$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

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

    You can automate adding multiple kubeconfigs to the KUBECONFIG environment variable with the following script. Add it to your shell rc file (e.g., .bashrc or .zshrc):

    # If there's already a kubeconfig file in ~/.kube/config it will import that too and all the contexts
DEFAULT_KUBECONFIG_FILE="$HOME/.kube/config"
if test -f "${DEFAULT_KUBECONFIG_FILE}"
then
  export KUBECONFIG="$DEFAULT_KUBECONFIG_FILE"
fi

# Your additional kubeconfig files should be inside ~/.kube/config-files
ADD_KUBECONFIG_FILES="$HOME/.kube/config-files"
mkdir -p "${ADD_KUBECONFIG_FILES}"

OIFS="$IFS"
IFS=$'\n'
for kubeconfigFile in `find "${ADD_KUBECONFIG_FILES}" -type f -name "*.yml" -o -name "*.yaml"`
do
    export KUBECONFIG="$kubeconfigFile:$KUBECONFIG"
done
IFS="$OIFS"

    ⚠️ Warning: The above script conflicts with kubectx. If you want to use both, you should merge the configs:

    kubectl config view --merge --flatten > $HOME/.kube/merged-config
export KUBECONFIG="$HOME/.kube/merged-config"

    ⚡ Commands

    🌐 Networking

    • Connect Containers via Kubernetes DNS
      <service-name>.<namespace>.svc.cluster.local

    • Troubleshoot Networking
      Use the 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

    • Execute Commands on Pods:

      kubectl exec -it <PODNAME> -- <COMMAND>
kubectl exec -it generic-pod -- /bin/bash

    🛠️ Config and Cluster Management

    CommandDescription
    kubectl cluster-infoDisplay endpoint information about the master and services.
    kubectl config viewGet the configuration of the cluster.

    📦 Resource Management

    CommandDescription
    kubectl get all --all-namespacesList all resources in the entire cluster.
    kubectl delete <RESOURCE> <RESOURCENAME> --grace-period=0 --forceForce the deletion of the resource.

    🔢 Kubernetes Resource Short Names

    Short NameLong Name
    csrcertificatesigningrequests
    cscomponentstatuses
    cmconfigmaps
    dsdaemonsets
    deploydeployments
    ependpoints
    evevents
    hpahorizontalpodautoscalers
    ingingresses
    limitslimitranges
    nsnamespaces
    nonodes
    pvcpersistentvolumeclaims
    pvpersistentvolumes
    popods
    pdbpoddisruptionbudgets
    psppodsecuritypolicies
    rsreplicasets
    rcreplicationcontrollers
    quotaresourcequotas
    saserviceaccounts
    svcservices

    🧰 Logs and Troubleshooting

    🔍 Logs

    • Access MySQL Client Logs:

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

    • Troubleshoot Networking with Netshoot:

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

    🚨 Resources Stuck in Terminating State

    You can resolve stuck resources using the following method:

    (
NAMESPACE=longhorn-demo-1
kubectl proxy &
kubectl get namespace $NAMESPACE -o json | jq '.spec = {"finalizers":[]}' > temp.json
curl -k -H "Content-Type: application/json" -X PUT --data-binary @temp.json 127.0.0.1:8001/api/v1/namespaces/$NAMESPACE/finalize
)

    Tags 📚

    #kubectl #kubernetes #cli #cluster-management #resource-management

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