Core Commands — Managing the Restaurant

The manager has learned the vocabulary. Now it's time to give orders. kubectl is the manager's walkie-talkie — every command you type goes to the Kubernetes API server, which tells the cluster what to do.

0 · Setup — Connecting to the Restaurant

Check kubectl is installed

kubectl version --client

Client Version: v1.28.x

Check cluster connection

kubectl cluster-info

Kubernetes control plane is running at https://k8s-cluster:6443

Remember

kubectl talks to the API server. If kubectl cluster-info fails, check your kubeconfig (~/.kube/config).

1 · kubectl apply — Handing the Blueprint to the Manager

Apply a manifest file

kubectl apply -f deployment.yaml

deployment.apps/campus-library created

Apply everything in a folder

kubectl apply -f k8s/

Remember

apply is declarative — you describe what you want, and Kubernetes figures out how to get there. This is the recommended way to manage resources.

2 · kubectl get — What's Cooking?

See all Pods

kubectl get pods

NAME                            READY   STATUS    RESTARTS   AGE
campus-library-7d4b8c9f-x2k4m  1/1     Running   0          5m
campus-library-7d4b8c9f-a9n3p  1/1     Running   0          5m
campus-library-7d4b8c9f-q8w2r  1/1     Running   0          5m

See Deployments

kubectl get deployments

See Services

kubectl get services

See everything in a namespace

kubectl get all -n campus-dev

See all resources across all namespaces

kubectl get all --all-namespaces

Remember

kubectl get is your compass. Run it whenever you're lost — it always tells you what's running.

3 · kubectl describe — What's Wrong with This Chef?

When a Pod isn't healthy, describe gives you the details:

Describe a specific Pod

kubectl describe pod campus-library-7d4b8c9f-x2k4m

The output includes events at the bottom — this is where you'll find errors like image pull failures, crash loops, and resource issues.

Describe a Deployment

kubectl describe deployment campus-library

Remember

get shows the summary. describe shows the details. If get shows a problem, describe tells you why.

4 · kubectl logs — What Did the Chef Say?

See logs of a Pod

kubectl logs campus-library-7d4b8c9f-x2k4m

Library running on port 3000

Follow logs in real time

kubectl logs -f campus-library-7d4b8c9f-x2k4m

Logs from a previous container (if it crashed)

kubectl logs --previous campus-library-7d4b8c9f-x2k4m

Remember

kubectl logs is your debugging tool. If a Pod is in CrashLoopBackOff, check the logs first.

5 · kubectl exec — Opening a Chef's Lunch Box

Open a shell inside a running Pod

kubectl exec -it campus-library-7d4b8c9f-x2k4m -- bash

root@campus-library-7d4b8c9f-x2k4m:/#

Run a single command

kubectl exec campus-library-7d4b8c9f-x2k4m -- cat /app/server.js

Remember

kubectl exec is for debugging. If you find yourself using it often, something is wrong with the container's configuration.

6 · kubectl scale — Hiring More Chefs

Scale a Deployment

kubectl scale deployment campus-library --replicas=5

deployment.apps/campus-library scaled

Verify

kubectl get pods

NAME                            READY   STATUS    RESTARTS   AGE
campus-library-7d4b8c9f-x2k4m  1/1     Running   0          10m
campus-library-7d4b8c9f-a9n3p  1/1     Running   0          10m
campus-library-7d4b8c9f-q8w2r  1/1     Running   0          10m
campus-library-7d4b8c9f-m3j5n  1/1     Running   0          10s
campus-library-7d4b8c9f-k8p2w  1/1     Running   0          10s

Remember

Scaling is instant. Kubernetes starts new Pods immediately. Scale down to remove them.

7 · kubectl delete — Sending Chefs Home

Delete a resource

kubectl delete -f deployment.yaml

Delete by name

kubectl delete pod campus-library-7d4b8c9f-x2k4m

Common mistake

Deleting a Pod managed by a Deployment causes the Deployment to recreate it. To truly remove Pods, delete the Deployment.

8 · kubectl rollout — Watching the Kitchen Update

Check rollout status

kubectl rollout status deployment/campus-library

deployment "campus-library" successfully rolled out

See rollout history

kubectl rollout history deployment/campus-library

Rollback if something goes wrong

kubectl rollout undo deployment/campus-library

Remember

rollout undo is your emergency button. If a new image is broken, rollback is instant.

Cheat Sheet

Command	Restaurant meaning
kubectl apply -f	Hand the blueprint to the manager
kubectl get	What's cooking?
kubectl describe	What's wrong with this chef?
kubectl logs	What did the chef say?
kubectl exec	Open a chef's lunch box
kubectl scale	Hire more chefs
kubectl delete	Send chefs home
kubectl rollout	Watch the kitchen update
kubectl rollout undo	Emergency rollback