Comment 4 for bug 1924123

I will put my cent in this bug as I was impacted by it recently. I will add that this bug not only apply in case of reduction of the host hardware inventory (so hardware failure), but also in case of the reduction of the overallocation ratio, which can be much more common and allowed by the API.

Indeed, if a host is considered as full with a given allocation ratio (either for CPU/RAM or DISK), reducing it will put the host in this overallocated state, and we won't be able to live migrate, or even resize any VM on the host.

As an operator perspective, reducing the overallocation ratio then migrate some VM to match this new ratio can be a common use-case.