[andydd]

Can you confirm that it's impossible to avoid downtime, even with HA, because of forced updates?

Surely that's what HA is? no downtime as you update each node one at a time?

If it's impossible then it's a dealbreaker.

[flamingcow]

[I'm the Cloud SQL TL] Confirmed. We know it's a problem that we need to fix. HA reduces downtime in unexpected failure cases (live migration for your primary only helps in planned shutdown cases, not if the physical machine fails), but doesn't currently help with maintenance-related downtime.