Does the rolling update with state full set replica 1 work

Question

If i have set the rolling update for a statefull replica=1. Will this work?

Answer 1

• No, because there is only 1 replica, any changes to state full set would result in an outage. 

• So rolling update of a StatefulSet would need to tear down one (or more) old pods before replacing them. 

• In case 2 replicas, a rolling update will create the second pod, which it will not be succeeded, the PD is locked by first (old) running pod, the rolling update is not deleting the first pod in time to release the lock on the PDisk in time for the second pod to use it. 

• If there's only one that rolling update goes 1 -> 0 -> 1.f the app can run with multiple identical instances concurrently, use a Deployment and roll 1 -> 2 -> 1 instead.