My Google Load Balancers never move.. It is a single thing that points each node (physical machine) in the cluster, and distributes traffic between then.

Each node knows how to route traffic to each app. So when I deploy that app, the software load balancer at the node level will slowly move traffic over from old app to new app. Entire thing is MAGICAL. And 0 downtime, very very fast deploys.

Edit - But yes this explains iy. Changing the google load balancers is like a 5 minute ordeal. Total pain. Nice that with GKE you only need to touch them when your node count changes, which can be very rare (~monthly for me)