[ops][nova] How to update from N to N+3 (and manage nova services that don't start because they find too old compute nodes...)

Dear all

When we upgraded our Cloud from Rocky to Train we followed the following procedure:

1) Shutdown of all services on the controller and compute nodes 2) Update from Rocky to Stein of controller (just to do the dbsyncs) 3) Update from Stein to Train of controller 4) Update from Rocky to Train of compute nodes

We are trying to do the same to update from Train to Xena, but now there is a problem because nova services on the controller node refuse to start since they find too old compute nodes (this is indeed a new feature, properly documented in the release notes). As a workaround we had to manually modify the "version" field of the compute nodes in the nova.services table.

Is it ok, or is there a cleaner way to manage the issue ?

Thanks, Massimo