After deleting VMs in the UNKNOWN state, more checks of the host machine may be required. VMs may be put into the UNKNOWN state if there is an issue with a connection to the hypervisor. These VMs are marked as UNKNOWN.
If a user deletes a VM in this state, then it could remain in the hypervisor but it would not be registered on the platform. So the information in Abiquo may not be consistent with the state of the hypervisor and problems could occur. For example, if the user then redeploys their virtual appliance, this would create another VM on the hypervisor. So there would be two different virtual machines with the same name using the same external disk(s).
Therefore, the delete should only be performed by an authorized user who can check the hypervisor to ensure that the VM has been fully destroyed.
The "Delete unknown virtual machine" privilege controls whether users can delete virtual machines in an UNKNOWN state. This privilege is displayed in the virtual appliance privileges section. In addition, if the user is in a different enterprise, they will require the privilege to administer all enterprises.
This feature enables customers to ensure that information in Abiquo is consistent with the state of the hypervisor. It improves platform stability by enabling greater control over situations such as minor communication failures between the hypervisor and Abiquo.