Blue/Green

Here you can find a description and history of Blue/Green Deployment.

Make sure you are in the correct namespace

kubectl config set-context --current --namespace=myspace

Make sure nothing else is deployed:

kubectl get all

No resources found in myspace namespace.

Deploy V1 of myboot:

kubectl apply -f apps/kubefiles/myboot-deployment-resources-limits.yml

Scale to 2 replicas:

kubectl scale deployment/myboot --replicas=2

Watch and show-labels:

watch kubectl get pods --show-labels

Deploy the service:

kubectl apply -f apps/kubefiles/myboot-service.yml

Minikube
Hosted

IP=$(minikube ip -p devnation)
PORT=$(kubectl get service/myboot -o jsonpath="{.spec.ports[*].nodePort}")

If using a hosted Kubernetes cluster like OpenShift then use curl and the EXTERNAL-IP address with port 8080 or get it using kubectl:

IP=$(kubectl get service myboot -o jsonpath="{.status.loadBalancer.ingress[0].ip}")
PORT=$(kubectl get service myboot -o jsonpath="{.spec.ports[*].port}")

If you are in AWS, you need to get the hostname instead of ip.

IP=$(kubectl get service myboot -o jsonpath="{.status.loadBalancer.ingress[0].hostname}")

Curl the Service:

curl $IP:$PORT

And run loop script:

while true
do curl $IP:$PORT
sleep 0.8
done

Deploy V2 of myboot:

kubectl apply -f apps/kubefiles/myboot-deployment-resources-limits-v2.yml

Verify that the new pod/deployment carries the new code:

PODNAME=$(kubectl get pod -l app=myboot-next -o name)
kubectl exec -it $PODNAME -- curl localhost:8080

Bonjour from Spring Boot! 1 on myboot-next-66b68c6659-ftcjr

Now update the single Service to point to the new pod and go GREEN:

kubectl patch svc/myboot -p '{"spec":{"selector":{"app":"myboot-next"}}}'

Aloha from Spring Boot! 240 on myboot-d78fb6d58-929wn
Bonjour from Spring Boot! 2 on myboot-next-66b68c6659-ftcjr
Bonjour from Spring Boot! 3 on myboot-next-66b68c6659-ftcjr
Bonjour from Spring Boot! 4 on myboot-next-66b68c6659-ftcjr

Determine that you prefer Hawaiian (blue) to French (green) and fallback:

Now update the single Service to point to the new pod and go BLUE:

kubectl patch svc/myboot -p '{"spec":{"selector":{"app":"myboot"}}}'

Bonjour from Spring Boot! 17 on myboot-next-66b68c6659-ftcjr
Aloha from Spring Boot! 257 on myboot-d78fb6d58-vqvlb
Aloha from Spring Boot! 258 on myboot-d78fb6d58-vqvlb

Clean Up

kubectl delete service myboot
kubectl delete deployment myboot
kubectl delete deployment myboot-next