What would you like to be added:

Currently if you have a PDB spec like minAvailable: 1, and a HPA defining minReplicas=1 and maxReplicas=N, you may end up in a scenario where disruptions get "stuck" if the HPA has scaled to 1. At any point an increase in load could cause the HPA to scale up to 2+, allowing the PDB to be satisfied, which leads to a weird scenario where a disruption can only occur if there is high load.

Ideally, the PDB would be able to trigger the HPA to scale up to meet constraints. For example, if I have 1 replica and a disruption is triggered, scale up a new replica first, then terminate the old one. Given an HPA is in place, I have already clearly specified I am OK with my pod being scaled up, so this shouldn't have negative impact on stateful workloads.

Some more context: istio/istio#12602