What do you create duplicate VM uuids?

[tmilner]

I have a large customer that has 6 VMs with the same uuid... they are all powered off. How does he end up doing this? Is he cloning a powered-off VM over and over or are there other ways of creating VMs with duplicate ids? This is all from a single VC 2.5 (~70 esx servers). I'm assuming that when he powers up the VM will be assigned a new uuid... true?

Since UUIDs don't seem to be unique... is there something else I should be using (since the VMware managed object reference is not unique between VCs)?

TIA,

Tom

[tos2k · Accepted solution]

Correctly UUID is not unique. Cloning VMs keeps the existing UUID. When powering on the clone, you get asked if you want to have a new UUID or if you want to keep the existing. In some circumstances, f.e. backup, it is absolutely correct to keep the UUID. I think the MAC address of the virtual network card is also based on the UUID.

The UUID is contained by the vmx file, you can easily remove it from there to force a new one.

By the way:The vm-value that comes up via MOB is unique and so preferrable when needing i unique key.

Tos2k

[tmilner]

Thanks for the clarification "tos2k"... Unfortunately, my customers often have multiple VCs and I need to merge the data. Across multiple VCs the "vm-value" is not unique. I guess I need to come up with my own unique Unique-Id... maybe the UUID and VM managed object ref together Thanks again.

Tom

[tos2k]

Hi!

Assuming that there is no "uniqueness synchronization" mechanism between different virtual center instances, I think it could be worth (for you) to clearify what exactly you need the uniqueness for. If you want to detect "equal" VMs for example, you cant take vm.value or UUID. UUID is possibly a hint as it as a connection to the MAC address of the network adapter, but additionally I would advice to consider the VM spec and virtual disks spec.

Tos2k

[tmilner]

These large customers produce various performance & accounting reports on VMs, esx hosts, networks, etc. And this data may come from multiple VCs (take any company with multiple datacenters as an example). One customer raised the issue of VM's with the same UUID but different names and VMware-IDs.

Since powered-off VMs are included in the VMware inventory, it is unfortunate that VMware chose to provide "unique IDs" only when a VM is powered up, rather than when created (even if by cloning).

Tom