Kubernetes Imperative Commands

k8s_cheatsheet.md

Create a pod

kubectl run NAME --image=image [--env="key=value"] [--port=port] [--dry-run=server|client] [--overrides=inline-json] [--command] -- [COMMAND] [args...] [options]

create nginx pod with env vars exposed on port 80

kubectl run nginx-pod --image=nginx --env="DNS_DOMAIN=cluster" --env="SOME_SECRET=secret" --port=80

create python pod and print the version number.

kubectl run py-command --image=python:3.11-buster --restart=Never --command -- 'python' '-V'

Create a service

Nodeport

kubectl create service nodeport my-ns --tcp=8085:80 --node-port=30800

expose a od on a nodeport

kubectl expose pod nginx-pod --port=8080 --type=NodePort --target-port=80

Deployments

Create deployments

Create actual deployment

kubectl create deployment nginx --image=nginx --port=80

create deployment manifest file

kubectl create deployment nginx --image=nginx --port=80 --dry-run=client -o yaml > deployment.yaml

Update deployment image

kubectl set image (-f FILENAME | TYPE NAME) CONTAINER_NAME_1=CONTAINER_IMAGE_1

update the deployment above from nginx:1.21.1 to 1.23.2

kubectl set image deployment/nginx nginx=nginx:1.23.2

Rollouts

Check rollout status

Get the deployemnt name

kubectl get deployments

NAME    READY   UP-TO-DATE   AVAILABLE   AGE
nginx   1/1     1            1           11m

Check the status

kubectl rollout status deployment/nginx

deployment "nginx" successfully rolled out

Rollback

Undo the latest rollout

kubectl rollout undo deployment/nginx

Rollback to a specific rollout

kubectl rollout history deployment/nginx

kubectl rollout history deployment/nginx
deployment.apps/nginx
REVISION  CHANGE-CAUSE
1         <none>
2         <none>

Rollback to revision 1

kubectl rollout undo deployment/nginx --to-revision=1
deployment.apps/nginx rolled back

monitoring.md

Metrics API

1. Install metrics server to provide data
2. Access metrics data using kubectl top command