Kubernetes Intro

Links

• Kubernetes Docs
• Kubernetes Cheat Sheet
• Certifications
  • CKAD
  • CKA
  • CKS

Aliases are your friend

When working with the command line you'll be typing a LOT of things repeatedly. You can easily create alias for common commands to speed up your typing. The most common is to alias k=kubectl to save yourself from typing kubectl over and over again.

In your .bashrc or .zshrc files add the following

alias k=kubectl

Common Commands

Here are some of the commands you will use most commonly when working with your cluster

# Context Management
kubectl config get-contexts # List all current contexts in ~/.kube/config
kubectl config set-context --current --namespace default # Set default namespace

# Apply Changes
kubectl apply -f <file path/url>
kubectl delete -f <file path/url>

# Gets
kubectl get ns # Get Namespaces
kubectl get pods # Get Pods
kubectl get rs # Get Replica Sets
kubectl get deploy # Get Deployments
kubectl get svc # Get Services
kubectl get ds # Get Daemonsets
kubectl get secrets # Get Secrets
kubectl get configmaps # Get Config Maps

# Deletes
kubectl delete ns # Delete Namespaces
kubectl delete pods # Delete Pods
kubectl delete rs # Delete Replica Sets
kubectl delete deploy # Delete Deployments
kubectl delete svc # Delete Services
kubectl delete ds # Delete Daemonsets
kubectl delete secrets # Delete Secrets
kubectl delete configmaps # Delete Config Maps

# Describe a resource
kubectl describe <pod,svc,etc>

# Deletes with force
kubectl delete <pod,ds,rs,etc> --grace-period=0 --force

# Check pod/container logs
kubectl logs <pod> # -f will 'follow'
# If the pod has more than one container
kubectl logs <pod> -c <container name>

In scripts it's often helpful to execute fully from within the script rather than referencing external files. The Linux "cat <<EOF" syntax is very helpful for this.

cat << EOF|kubectl apply -f -
apiVersion: v1
kind: Pod
metadata:
  labels:
    run: ubuntu
  name: ubuntu
spec:
  containers:
  - image: ubuntu
    name: ubuntu
    command: [ "/bin/bash", "-c", "--" ]
    args: [ "while true; do sleep 30; done;" ]
  restartPolicy: Never
EOF

Kubectl Extensions

You can easily extend kubectl to enable your own shortcuts and additional features. Details are here. Many people have created extensions you can leverage. Here are a few of my favorites.

• kubectx
• ssh-jump

Not technically a plugin, but still very useful for cluster navigation:

• k9s

And don't forget the kubernetes and docker extensions for vscode.

• Kubernetes
• Docker