Currently vTPM requires that the cluster admin set the default storage provider used for backing TPMs. Furthermore, vTPM mandates that the backing store support RWX. This unfortunately pevents Windows VMs in particular from ever booting at all on clusters that only have RWO storage available.

This story is about removing the requirement that vTPM must have RWX. Instead KubeVirt should impose a NotMigratable condition if RWO is used.

As part of this, admins setting the backing store should not be mandatory. KubeVirt should simply interrogate CDI to find out whether or not the default store is in fact RWX. If the cluster admin chooses to set the store manually, this should still be honored.