rolling-update.md

Rolling update

• Canary a new release for live testing
• Roll out the new release using a replication controller rolling-update

Launch a new canary

Use kubectl to create a new replication controller, with a single pod that uses version 1.1.0 of the application.

kubectl create -f rc-canary.yml

Validate the replication controller

kubectl get rc

Apply rolling-update with the new release

Assuming the canary worked satisfactorily, now is the time to release this version (and new features) so it accessible by all end users. The rolling-update will create a new replication controller and scale up the replicas as it scales down the replicas in the 'old' replication controller (with version 1.0.0 pods).

kubectl rolling-update simple-cms --update-period=5s -f rc-new.yml

Watch the update live

If you like, watch the pods with kubectl.

kubectl get pods --watch

And also with a loop, curling the web page (remember, $IP refers to the service IP as before.

while true; do curl http://$IP; sleep 1; done

Next up: if time permits, deploy an Nginx proxy for SSL termination.