9 imperative kubectl commands that save CKA exam time

Quick reference

Make objects in one line

# a pod, instantly
$kubectl run nginx --image=nginx
# a deployment with replicas
$kubectl create deploy web --image=nginx --replicas=3
# a service in front of it
$kubectl expose deploy web --port=80

Let kubectl write the YAML

# print the YAML instead of creating it
$kubectl run nginx --image=nginx --dry-run=client -o yaml
# save it, edit it, then apply
$kubectl create deploy web --image=nginx --dry-run=client -o yaml > web.yaml
# apply your edited version
$kubectl apply -f web.yaml

Scale, update, roll back

# change replica count live
$kubectl scale deploy web --replicas=5
# roll out a new image version
$kubectl set image deploy/web nginx=nginx:1.27
# back to the previous version
$kubectl rollout undo deploy/web

Explained

Make objects in one line

kubectl run nginx --image=nginx creates a pod instantly. kubectl create deploy web --image=nginx --replicas=3 creates a deployment with replicas, the normal way to run something. kubectl expose deploy web --port=80 puts a service in front of it, so other pods can reach it by name.

Let kubectl write the YAML

kubectl run nginx --image=nginx --dry-run=client -o yaml prints the YAML instead of creating anything. This is the single biggest time-saver: let kubectl generate a correct skeleton. Redirect it to a file, edit the few fields you need, and kubectl apply -f web.yaml. Far faster and less error-prone than typing apiVersion and kind by hand.

Change fast

kubectl scale deploy web --replicas=5 changes the replica count live. kubectl set image deploy/web nginx=nginx:1.27 rolls out a new image version, triggering a rolling update. kubectl rollout undo deploy/web returns to the previous version in seconds, the fastest fix for a bad deploy.

The exam tip that applies everywhere: do not write YAML from a blank file. Generate it with --dry-run=client -o yaml, then edit. Also set an alias (alias k=kubectl) and learn kubectl explain for field names, since the docs are allowed in the exam.

In one line

Try it

$kubectl run p --image=nginx --dry-run=client -o yaml