Perform a rolling-action start-update

Set maxSurge to 0

Set maxUnavailable to 1

Perform a rolling-action start-update

Set maxSurge to 1

Set maxUnavailable to 0

Create a new managed instance group with an updated instance template

Add the group to the backend service for the load balancer

Once all instances in the new managed instance group are healthy, delete the old managed instance group

Create a new instance template with a new version of the application

Update the existing managed instance group with the new instance template

Recreate the instance using the new instance template by deleting the instances in the managed instance group