This material was gathered during my preparation for the CKA certification exam. I created and curated this cheatsheet with useful commands and information that will be handy to review before taking the exam.

If you want to know how to prepare for the CKA exam, check my How to pass CKA post.

Core Concepts

View resources in namespace dev:

kubectl get pods -n dev

View all pods in all namespaces:

kubectl get pods -A

View all resources in all namespaces:

kubectl get all -A

Generate a pod yaml file with nginx image and label env=prod:

kubectl run nginx --image=nginx --labels=env=prod --dry-run=client -o yaml > nginx_pod.yaml

Delete a pod nginx fast:

kubectl delete pod nginx --grace-period 0 --force

Generate Deployment yaml file:

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

Access a service test-service in a different namespace dev:

Create a service for a pod valid-pod, which serves on port 444 with the name frontend:

kubectl expose pod valid-pod --port=444 --name=frontend

Recreate the contents of a yaml file:

kubectl replace --force -f nginx.yaml

Edit details of a deployment nginx:

kubectl edit deploy nginx

Set image of a deployment nginx:

kubectl set image deploy nginx nginx=nginx:1.18

Scale deployment nginx to 4 replicas and record the action:

kubectl scale deploy nginx --repliacs=4 --record

Get events in current namespace:

kubectl get events


Get pods with their labels:

kubectl get pods --show-labels

Get the pods that are labeled env=dev:

kubectl get pods -l env=dev

Get taints of node node01:

kubectl describe node node01 | grep -i Taints:

Label node node01 with label size=small:

kubectl label nodes node01 size=small

Default static pods path:


Check pod nginx logs:

kubectl logs nginx

Check pod logs with multiple containers:

kubectl logs <pod_name> -c <container_name>


Check node resources usage:

kubectl top node

Check pod and their containers resource usage:

kubectl top pod --containers=true

Application Lifecycle Management

Check rollout status of deployment app:

kubectl rollout status deployment/app

Check rollout history of deployment app:

kubectl rollout history deployment/app

Undo rollout:

kubectl rollout undo deployment/app

Create configmap app-config with env=dev:

kubectl create configmap app-config --from-literal=env=dev

Create secret app-secret with pass=123:

kubectl create secret generic app-secret --from-literal=pass=123

Cluster Maintenance

Drain node node01 of all workloads:

kubectl drain node01

Make the node schedulable again:

kubectl uncordon node01

Upgrade cluster to 1.18 with kubeadm:

kubeadm upgrade plan
apt-get upgrade -y kubeadm=1.18.0-00
kubeadm upgrade apply v1.18.0
apt-get upgrade -y kubelet=1.18.0-00
systemctl restart kubelet

Backup etcd:

export ETCDCTL_API=3
etcdctl \
--endpoints= \
--cacert=/etc/kubernetes/pki/etcd/ca.crt \
--cert=/etc/kubernetes/pki/etcd/server.crt \
--key=/etc/kubernetes/pki/etcd/server.key \
snapshot save /tmp/etcd-backup.db

Restore etcd:

ETCDCTL_API=3 etcdctl snapshot restore /tmp/etcd-backup.db --data-dir /var/lib/etcd-backup

After edit /etc/kubernetes/manifests/etcd.yaml and change /var/lib/etcd to /var/lib/etcd-backup.


Create service account sa_1

kubectl create serviceaccount sa_1

Check kube-apiserver certificate details:

openssl x509 -in /etc/kubernetes/pki/apiserver.crt -text -noout

Approve certificate singing request for user john:

kubectl certificate approve john

Check the current kubeconfig file:

kubectl config view

Check current context:

kubectl config current-context

Use context dev-user@dev:

kubectl config use-context prod-user@production

Validate if user john can create deployments:

kubectl auth can-i create deployments --as john

Create role dev to be able to create secrets:

kubectl create role dev --verb=create --resource=secret

Bind the role dev to user john:

kubectl create rolebinding dev-john --role dev --user john

Check namespaced resources:

kubectl api-resources --namespaced=true


View all the kube-system related pods:

kubectl get pods -n kube-system

Check if all nodes are in ready state:

kubectl get nodes

Check memory, cpu and disk usage on node:

df -h

Check status of kubelet service on node:

systemctl status kubelet

Check kubelet service logs:

sudo journalctl -u kubelet

View kubelet service details:

ps -aux | grep kubelet

Check cluster info:

kubectl cluster-info

Gather info

Find pod CIDR:

kubectl describe node | less -p PodCIDR

Get pods in all namespaces sorted by creation timestamp:

kubectl get pod -A --sort-by=.metadata.creationTimestamp

Find the service CIDR of node-master:

ssh node0master
cat /etc/kubernetes/manifests/kube-apiserver.yaml | grep range

Find which CNI plugin is used on node-master:

ls /etc/cni/net.d/

Find events ordered by creation timestamp:

kubectl get events -A --sort-by=.metadata.creationTimestamp

Find internal IP of all nodes:

kubectl get nodes -o jsonpath='{.items[*].status.addresses[?(@.type=="InternalIP")].address}'

General notes

  • To create a daemonset, use kubectl create deploy command to create a .yaml file and then change the kind and remove replicas & strategy.
  • To find the static pod manifest path, check the exec command of kubelet service or staticPodPath parameter of kubelet’s config file.
  • To create a static pod, place a yaml definition file in the staticPodPath directory.
  • To identify static pods look for the suffix -<node_name> on pods.
  • To add a new scheduler copy the existing one and add to the container’s command the flags--leader-elect=false and --scheduler-name=my-scheduler-name. To use the new scheduler under spec of a pod definition file specify the option schedulerName.
  • To add a default command to a pod use command that overrides the default ENTRYPOINT from Dockerfile. Use args to override the Dockerfile CMD command for the commmand’s extra parameters.