Re-provisioning a failed server to solve the problem and taking a deep dive to find the root cause are not mutually exclusive. Essentially all VM software will allow you to snapshot/backup/clone the VM for later analysis, while also fixing your production environment _now_.

When you have a service which is acting weirdly, ideally I'd like to snapshot the VM, then do whatever I need to do to repair the service urgently.

That might involve making a new VM from scratch, but it also might twiddling some settings, or other emergency changes.

Afterwards, I want to be able to restore the VM state, probably in a firewalled off environment, so I can debug exactly what was wrong.

Sometimes I'd like to do it to a set of VM's - for example, if there is some DNS wierdness, I might want to snapshot an application server and a DNS server.

So far, no cloud provider seems to offer functionality to make that easy, which is a bit disappointing.