Macaddress duplicated on two different vCenter

[blackmscloud]

HI,

I'm experimeting a problem, I have two vCenter Server on different networks, that has the same macaddress in every network card (3).

The vCenter Server isn't implements an algoritm to avoid this case? Generating the MAC starting with the UUID?

Any of you has every experimented this?

There is a way to avoid this thing? I have any vCenter Servers and if this happens on the same L2 network should be a big problem.

Thanks for your time,

Alessio

[Rubeck]

Make sure that your vCenter servers run with different vCenter server Unique ID's (set in vCenter server settings/ Runtime Settings). This ID is used in calculating MAC addresses for VMs..

/Rubeck

[schepp]

The UUIDs of the VMs are generated by using your vCenters Unique ID. So as long as your Unique IDs are different there won't be any duplicate MACs or UUIDs.

in vCenter: Administration -> vCenter Server settings -> runtime settings -> look at unique ID

Regards

Edit: Rubeck was faster

[blackmscloud]

Guys, thanks for your reply, but the problem is that the UUID is different! It's strange I know... How could it be possible?

[peetz · Accepted solution]

What do you mean? Do the two vCenter servers themselves have conflicting MAC addresses, or are there VMs managed by each of the vCenter servers with same MAC addresses?

In the first case: If the vCenter servers are virtual, are they managed by the same vCenter server (a third one or one of the both)?

If it's the second case: This really should not happen if the UUIDs are really different. See http://kb.vmware.com/kb/1024025 for a resolution.

- Andreas

[blackmscloud]

The two vcenter are virtual, and they are on a Hyper-V host.They are on two separated networks but still the UUID are different, is it normal?

[peetz]

Okay, the UUID of a vCenter server determines what MAC addresses it assign to VMs that are managed by this vCenter server.

It has nothing to do with its own MAC addresses. In your case these are determined by the HyperV-host that is running the vCenter VM.

So, if you have two virtual vCenter servers with same MAC addresses and both are running on the same Hyper-V machine, then there is something wrong with the configuration of the Hyper-V host. This is not the right forum to ask for help then, but maybe here is a solution for you:

http://www.thedailyadmin.com/2011/07/duplicate-mac-addresses-in-scvmm-and.html

- Andreas