Kubernetes-Cheat-sheet.txt

Kubernetes Essentials - 2 Days

Lab 8: Kubernetes Operations on AWS
Task 2: Setting up a Kubernetes Cluster

wget https://kops-script.s3.amazonaws.com/kops-v1.25.sh
. ./kops-v1.25.sh
export KOPS_STATE_STORE=s3://< Your Cluster_Name >
kops validate cluster
sudo hostnamectl set-hostname kops

Lab 1: Services in Kubernetes
Task 1: Create a Pod using a YAML file

kubectl get nodes
kubectl get nodes -o wide

wget https://hpe-content.s3.ap-south-1.amazonaws.com/httpd-pod.yaml

kubectl create -f httpd-pod.yaml
kubectl get pods
kubectl get pods -o wide
kubectl get pod httpd-pod -o yaml
kubectl describe pod httpd-pod 
kubectl get pods --show-labels

Task 2: Setup ClusterIP service

wget https://hpe-content.s3.ap-south-1.amazonaws.com/httpd-svc.yaml

kubectl apply -f httpd-svc.yaml
kubectl get services
kubectl describe svc httpd-svc
kubectl get ep 
kubectl get svc httpd-svc

curl http://< replace Cluster_IP>:< replace Service_Port>

kubectl get nodes -owide | awk '{print $7}'

ssh -t admin@< replace Node_IP> curl < replace Cluster_IP>:< replace Service_Port>

Task 3: Setup NodePort service

vi httpd-svc.yaml

# Replace the content of httpd-svc.yaml with below content use ESc and :wq! to quit vi

apiVersion: v1
kind: Service
metadata:
  name: httpd-svc
spec:
  selector:
    env: prod 
    type: frontend
    app: httpd-ws
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80
  type: NodePort

# End of file

kubectl apply -f httpd-svc.yaml

kubectl get svc 
kubectl describe svc httpd-svc
kubectl get nodes -owide | grep node | awk '{print $7}'
curl http://<Your NODE_EXTERNAL_IP>:<Your NodePort>

Task 4: Setup LoadBalancer service

vi httpd-svc.yaml

# Replace the content of httpd-svc.yaml with below content use ESc and :wq! to quit vi

apiVersion: v1
kind: Service
metadata:
  name: httpd-svc
spec:
  selector:
    env: prod
    type: frontend
    app: httpd-ws
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80
  type: LoadBalancer


# End of file

kubectl apply -f httpd-svc.yaml
kubectl describe svc httpd-svc
curl http://<Your LoadBalancer_Ingress>:<Your Service_Port>

Task 5: Delete and recreate httpd Pod

kubectl get pod httpd-pod -o wide
kubectl describe svc httpd-svc
kubectl delete pod httpd-pod
kubectl describe svc httpd-svc
kubectl create -f httpd-pod.yaml
kubectl get pod httpd-pod -o wide
kubectl describe svc httpd-svc

Task 6: Clean-up

kubectl delete -f httpd-pod.yaml
kubectl delete -f httpd-svc.yaml


Lab 2: Deployment
Task 1: Write a Deployment YAML and Apply it

wget https://hpe-content.s3.ap-south-1.amazonaws.com/dep-nginx.yaml
kubectl apply -f dep-nginx.yaml
kubectl get deployments
kubectl get rs
kubectl get pods

kubectl exec -it <replace pod_name> -- /bin/bash
nginx -v
exit

Task 2: Update the Deployment with a newer image

kubectl set image deployment/nginx-dep nginx-ctr=nginx:1.11 --record
kubectl describe deployments
kubectl get pods

kubectl exec -it <replace pod_name> -- /bin/bash
nginx -v
exit

Task 3: Rollback of Deployment 

kubectl rollout history deployment/nginx-dep
kubectl rollout undo deployment/nginx-dep --to-revision=1
kubectl get pods

kubectl exec -it <replace pod_name> -- /bin/bash
nginx -v
exit

Task 4: Scaling of Deployments

kubectl get deployments
kubectl get pods

kubectl scale deployment nginx-dep --replicas=8
kubectl get deployments
kubectl get pods

kubectl scale deployment nginx-dep --replicas=2
kubectl get deployments
kubectl get pods

kubectl delete -f dep-nginx.yaml


Lab 3: DaemonSet in Kubernetes

wget https://hpe-content.s3.ap-south-1.amazonaws.com/ds-pod.yaml

kubectl apply -f ds-pod.yaml
kubectl get ds fluent-ds
kubectl get pods -o wide
kubectl delete -f ds-pod.yaml

Lab 4: Persistent Volume in Kubernetes

Task 1: Get Node Label and Create Custom Index.html on Node

kubectl get nodes --show-labels | grep role=node
kubectl get nodes -o wide | grep node
ssh admin@< replace selected node_public_IP>
sudo su
mkdir /pvdir
echo Hello World! > /pvdir/index.html
exit
exit

Task 2: Create a Local Persistent Volume

wget https://hpe-content.s3.ap-south-1.amazonaws.com/pv-volume.yaml
kubectl apply -f pv-volume.yaml
kubectl get pv 

Task 3: Create a PersistentVolumeClaim

wget https://hpe-content.s3.ap-south-1.amazonaws.com/pv-claim.yaml
kubectl apply -f pv-claim.yaml
kubectl get pvc 
kubectl get pv

Task 4: Create nginx Pod with NodeSelector

wget https://hpe-content.s3.ap-south-1.amazonaws.com/pv-pod.yaml

vi pv-pod.yaml
# Replace the <Your Node Hostname> with the nodename in which you created index.html. Press ESc and :wq! to save and exit vi

kubectl apply -f pv-pod.yaml
kubectl get pods -o wide
kubectl exec -it pv-pod -- /bin/bash 
apt-get update
apt-get install curl -y
curl localhost

kubectl delete -f pv-pod.yaml
kubectl delete -f pv-claim.yaml
kubectl delete -f pv-volume.yaml

Lab 5: StatefulSet Implementation
Task 1:  Creating a StatefulSet

wget files.cloudthat.training/devops/kubernetes-essentials/nginx-sts.yaml

kubectl apply -f nginx-sts.yaml

kubectl get service nginx-svc 
kubectl get statefulset nginx-sts
kubectl get pods -w -l app=nginx-sts

for i in 0 1; do kubectl exec "nginx-sts-$i" -- sh -c 'hostname'; done

kubectl run -i --tty --image busybox:1.28 dns-test --restart=Never --rm

nslookup nginx-sts-0.nginx-svc
nslookup nginx-sts-1.nginx-svc

exit

kubectl delete pod -l app=nginx-sts
kubectl get pod -w -l app=nginx-sts

for i in 0 1; do kubectl exec "nginx-sts-$i" -- sh -c 'hostname'; done

Task 2: Writing to a Scalable Storage

kubectl get pvc -l app=nginx-sts

for i in 0 1; do kubectl exec "nginx-sts-$i" -- sh -c 'echo "$(hostname)" > /usr/share/nginx/html/index.html'; done

for i in 0 1; do kubectl exec -i -t "nginx-sts-$i" -- curl http://localhost/; done

Task 3: Scaling StatefulSet

kubectl scale sts nginx-sts --replicas=5
kubectl get pods -w -l app=nginx-sts

kubectl get pods -l app=nginx-sts
kubectl get pvc -l app=nginx-sts

kubectl edit sts nginx-sts

# Set spec: replicas to 3, Press Esc and :wq! to exit vi

kubectl get pods -w -l app=nginx-sts
kubectl get pvc -l app=nginx-sts

Task 4: Rolling Update

kubectl edit sts nginx-sts

# Change the spec: conatiners: image value to nginx:latest, Press Esc and :wq! to exit vi

kubectl get pod -l app=nginx-sts -w
kubectl get pods
kubectl describe pod nginx-sts-0 | grep Image
kubectl delete -f nginx-sts.yaml

Task 5: Clean-up Resources

kubectl delete -f nginx-sts.yaml 

Lab 6: Namespaces and Resource Quotas in Kubernetes

Task 1: Creating a Namespace
kubectl create namespace quotas
kubectl get namespaces 

Task 2: Creating a resourcequota
wget https://hpe-content.s3.ap-south-1.amazonaws.com/rq-quotas.yaml

Task 3: Verify resourcequota Functionality
wget https://hpe-content.s3.ap-south-1.amazonaws.com/rq-pod.yaml


Additional Topic: Installing Helm 3 in Ubuntu Linux and installing wordpress through Helm.

wget files.cloudthat.training/devops/kubernetes-essentials/helm.sh
cat helm.sh
bash helm.sh
helm version
helm repo add bitnami https://charts.bitnami.com/bitnami
helm repo update
helm repo list
helm search repo wordpress
helm install wordpress-chart bitnami/wordpress
helm uninstall wordpress-chart


####### IMPORTANT - DELETE THE CLUSTER FROM AWS #######

kops delete cluster <Your Cluster_Name> --yes

#if the command shows error, try

export KOPS_STATE_STORE=s3://< Your Cluster_Name >
kops validate cluster
kops delete cluster <Your Cluster_Name> --yes

# Verify all the AWS resources are deleted from AWS Console, in case of any confusions, feel free to reach us.