When I launch a new instance, what is the likelyhood that I will be on a different host than the other instances I already have? I ask for fault tolerance reasons in cases where I want to launch two instances and load balance them.
The scheduler looks at available resources across all hypervisor hosts to determine where it places your instance. There is a chance two instances could be placed on the same hypervisor.
In my testing, I haven’t been had two instances placed on the same hypervisor when I launched at the same time. Though, like I said above, it’s still possible. There is a higher chance they will be on the same hypervisor if they are booted at separate times.