Nexus 1000V: VEM UUID's are identical on four different ESXi hosts

[t.hombach]

Hi there,

I have an urgent problem with a new ESXi 5 installation including Nexus 1000V.

4x fresh installed and updated ESXi 5 Servers with Nexus 1000V, latests Version. 1000V install through OVF-Template, configured as Layer-3.

Both VSM's are up and runnig. In the show module I can see both VSM's and only one VEM. I discovered on every ESXi through 'vemcmd show card' that the card UUID is always the same. How can this happen?

The ESXi LUN's aren't cloned. Every ESXi has it's own Boot-LUN and was unique installed. I can change the card UUID manual with 'vemcmd card [new uuid]' and all VEM's are active in 'show module' and everything works fine. But this change isn't persistant. The UUID's changed back overnight.

Does anybody know how the card UUID's are generated and how I make the manual UUID change persistant?

Thank you

[t.hombach]

Hi there, me again.

I solved the problem by msyself. If you are interested in this condition here is my result:

The VEM UUID is equal to the ESXi UUID. If you start or restart the VEM 'vem start/restart' the function startDpa is called. startDpa calls a script in /opt/cisco/vXXX/nexus/vem-vXXX/shell/vssnet-functions and extracts the UUID from the ESXi host:

setBiosUuid()
{
         local UUID

        UUID=$(esxcfg-info -u | awk '{print tolower($1)}')

        if [ "${UUID}" != "" ] ; then
                 doCommand ${VEMCMD} card uuid vmware ${UUID}
         fi
}

As you can see the 'esxcfg-info -u' is used. Now can you set the UUID by manualy insert a UUID. Example:

setBiosUuid()
{
         local UUID

        UUID=$(esxcfg-info -u | awk '{print tolower($1)}')

        if [ "${UUID}" != "" ] ; then
                 doCommand ${VEMCMD} card uuid vmware 2d8a42e2-2d09-8737-b3ec-ca3f7cc2cf1d
         fi
}

This is not recommended!!! I still dont know why all four ESXi hosts have the same UUID... But thats not my problem ;-)

You can find the VEM files in /opt/cisco/vXXX/nexus/vem-vXXX/

If you change the UUID by using cmd 'vemcmd card [uuid]' or 'vemset card uuid [uuid]' it will work for a while... If the script above is called the UUID will be replaced by the ESXi UUID.

[mwronkow]

Hello,

Modifying the script is completely unsupported.  It would be best to determine why the 4 servers have the same UUID.  The UUID is generated from a burned in address.  In Cisco UCS, this number can be modified through service-profiles and is always unique withing the same UCS cluster. Other vendors sometimes allow this change through a utility or out-of-band management screen. What hardware vendor & model are the servers?

Matthew

[t.hombach]

Hi Matthew,

I know that modifying the script is not supported and I didn't recommend this to my client. The solution must be to determine why the UUID in ESXi are the same. My task was to install and configure only the 1000V and I had to prove that the duplicate UUID's aren't generated by the 1000V. Next steps must be done by the VMware guy...

And by the way the underlying server hardware is not a UCS... :-(

[Alex Knox]

Hi All,

I have a similar condition where 2 VEM's on separate clusters but managed by the same VCenter are duplicates.

The question is, what to do about so that it is a supported solution?

Kind regards,

Alex Knox

[mwronkow]

Hello Alex,

VEM UUID is same as found in esxinfo.  ESXi determines UUID from hardware.  What is the hardware?

[t.hombach]

Hi Alex,

my customer solved the problem by changing the UUID. All servers had the same UUID because they just created one service profile and copied it to multiple servers (not UCS but a simliar system with "service profiles"...).

Log into both ESXi host via SSH and check if "esxcfg-info -u" shows the same UUID.