What is Kubectl?

The kubectl, pronounced “kube-cuddle”, is the command line tool to control your Kubernetes clusters. Be sure to study the official kubernetes.io documentation for kubectl here.

Be sure to bookmark this awesome cheat sheet: Kubernetes Kubectl Cheat Sheat.

First lets learn to read the manual:

kubectl
kubectl controls the Kubernetes cluster manager.

 Find more information at: https://kubernetes.io/docs/reference/kubectl/overview/

Basic Commands (Beginner):
  create        Create a resource from a file or from stdin.
  expose        Take a replication controller, service, deployment or pod and expose it as a new Kubernetes Service
  run           Run a particular image on the cluster
  set           Set specific features on objects

Basic Commands (Intermediate):
  explain       Documentation of resources
  get           Display one or many resources
  edit          Edit a resource on the server
  delete        Delete resources by filenames, stdin, resources and names, or by resources and label selector

Deploy Commands:
  rollout       Manage the rollout of a resource
  scale         Set a new size for a Deployment, ReplicaSet or Replication Controller
  autoscale     Auto-scale a Deployment, ReplicaSet, or ReplicationController

Cluster Management Commands:
  certificate   Modify certificate resources.
  cluster-info  Display cluster info
  top           Display Resource (CPU/Memory/Storage) usage.
  cordon        Mark node as unschedulable
  uncordon      Mark node as schedulable
  drain         Drain node in preparation for maintenance
  taint         Update the taints on one or more nodes

Troubleshooting and Debugging Commands:
  describe      Show details of a specific resource or group of resources
  logs          Print the logs for a container in a pod
  attach        Attach to a running container
  exec          Execute a command in a container
  port-forward  Forward one or more local ports to a pod
  proxy         Run a proxy to the Kubernetes API server
  cp            Copy files and directories to and from containers.
  auth          Inspect authorization

Advanced Commands:
  diff          Diff live version against would-be applied version
  apply         Apply a configuration to a resource by filename or stdin
  patch         Update field(s) of a resource using strategic merge patch
  replace       Replace a resource by filename or stdin
  wait          Experimental: Wait for a specific condition on one or many resources.
  convert       Convert config files between different API versions
  kustomize     Build a kustomization target from a directory or a remote url.

Settings Commands:
  label         Update the labels on a resource
  annotate      Update the annotations on a resource
  completion    Output shell completion code for the specified shell (bash or zsh)

Other Commands:
  alpha         Commands for features in alpha
  api-resources Print the supported API resources on the server
  api-versions  Print the supported API versions on the server, in the form of "group/version"
  config        Modify kubeconfig files
  plugin        Provides utilities for interacting with plugins.
  version       Print the client and server version information

Usage:
  kubectl [flags] [options]

Use "kubectl <command> --help" for more information about a given command.
Use "kubectl options" for a list of global command-line options (applies to all commands).

How Do I Use Kubectl?

I am working with kubectl as I learn more about kubernetes, k8ssandra, Astra Service Broker, and DataStax Kubernetes Operator for Apache Cassandra. Normally I keep a personal document of commands I can reference quickly, but now with this blog, I can use this page for those future references. Now so can you!

Check out some commands I have used recently:

kubectl version

kubectl cluster-info

kubectl describe pods operatorhubio-catalog-tzv5l -n olm

kubectl describe CassandraDataCenter dc1

kubectl get pods --all-namespaces

kubectl get pods --all-namespaces -o wide

kubectl -n <namespace> get pods

kubectl get nodes -o wide

kubectl get secrets -n cass-operator

kubectl get secrets devdb -o yaml

kubectl get service --all-namespaces

kubectl get serviceinstances

kubectl get serviceinstances devdb

kubectl get servicebindings

kubectl get svc

kubectl get events

kubectl -n cass-operator get events

kubectl get pvc

kubectl -n cass-operator get pvc

kubectl get storageclasses

kubectl get sc

kubectl get deployments --namespace=monitoring

kubectl get cassandradatacenters

kubectl get serviceinstances devdb

kubectl get configmap

kubectl get configmap <name> -o yaml

kubectl get crds

kubectl get crds | grep cassandra | cut -d ' ' -f 1 | xargs kubectl delete crd

kubectl -n cass-operator get pods --selector name=cass-operator -o yaml

kubectl -n cass-operator get pods

kubectl -n cass-operator exec cluster1-dc1-default-sts-2 -- keytool -list -keystore keystore.jks -storepass dc1

kubectl logs -n <namespace> <pod>

kubectl -n cass-operator logs cluster1-dc1-rack1-sts-0 server-system-logger

kubectl -n <namespace> logs <pod> server-system-logger

kubectl logs -n cass-operator cluster1-dc1-default-sts-0 -c server-config-init

kubectl logs -n cass-operator cluster1-dc1-default-sts-0 -c server-system-logger

kubectl logs -n cass-operator cluster1-dc1-default-sts-0 -c cassandra

kubectl logs -n olm -p operatorhubio-catalog-tzv5l

kubectl -n <namespace> exec <pod> -- keytool -list -keystore keystore.jks -storepass dc1

kubectl apply -f astra-service-binding.yaml

kubectl create -f astra-service-broker.yaml

kubectl delete -f astra-service-broker.yaml

kubectl delete servicebinding devdb-azure

kubectl delete serviceinstance devdb-azure

kubectl delete -n kube-system pod traefik-5dd496474-q7fzk

kubectl exec -n cass-operator -i -t -c cassandra cluster1-dc1-default-sts-0 -- cqlsh -u cluster1-superuser -p <password>

kubectl port-forward prometheus-deployment-54686956bd-nhz2s 8080:9090 -n monitoring

kubectl port-forward svc/monitoring-grafana 3000:80

kubectl -n cass-operator exec --stdin cluster1-dc1-default-sts-0 -- /bin/bash

How Do I Make Kubectl Colorful?

Today I found this very kewl github repo kubecolor which makes the output of your kubectl commands colorful. How Cool!!

Kubecolor is super easy to install and super easy to use! Thank you: dty1er and kubecolor contributors for your amazing efforts.

How Do You Change Kubectl Context?

I am often switching from k3ds to gke or iks for testing my command flow in these other environments. The other day I connected to a gke cluster and needed to get my local terminal’s kubectl back to my local k3ds environment. These are the commands I needed to switch my kubectl context:

kubectl config get-contexts
kubectl config use-context k3d-k3s-default

To learn more about kubectl context check out this cheatsheet.

What’s Next?

Have some commands I am missing? I would love to see what you got. Reach out and lets talk kubectl!

How can I help you with Kubernetes?

Find me over on the DataStax Community to ask me any questions about Cassandra and Kubernetes. Also let’s chat if you have something kewl you did with Cassandra and Kubernetes and you want me to feature it in my blog. Look below or to the right for more ways to find me.