DevOps/Kubernetes/kubectl

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

To install in MacOS execute: brew install kubernetes-cli

kubectl info commands

• Verify running Pods:
  • kubectl get pods
  • kubectl get pod PODNAME
  • kubectl get pod PODNAME -n MY_NAMESPACE
  • kubectl get pod PODNAME -n MY_NAMESPACE --watch
• Fetch metrics for PODNAME pod kubectl top pod PODNAME

kubectl operation commands

• Connect to a Pod: kubectl exec -it YOUR_POD_NANE -- /bin/bash

kubectl delete/destroy commands

• kubectl delete namespace MY_NAMESPACE

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:
  • kubectl get apiservices
  • kubectl get nodes
  • kubectl get pods
  • kubectl get pod PODNAME -n NAMESPACE -o yaml | kubectl replace --force -f -

• 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.

See also

• EKS
• kubeadm tools for creating Kubernetes cluster.
• Certified Kubernetes Administrator