9.12.2011

ESXi Caches Old MAC address from UCS Service Profile

Per CSCte08176:

VMware's ESXi hypervisor caches the MAC address of it's physical NIC after it put's it in promiscuous mode.  If the administrator subsequently changes the mac-address value defined in the associated service profile for that blade, the NIC will have a new MAC address, while the older MAC is not removed or updated from the ESXi hypervisor.  This potentially leads to a MAC address conflict if the initial MAC address is re-assigned to a different blade (via service profile association).

One way to confirm this problem is by collecting "esxcfg-nics -l" and "esxcfg-vmknic -l", and comparing the mac-address output in both. The first one should correctly display the mac-address assigned in the service-profile while the second will display the cached mac-address.

VMware KB article: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1031111

As a workaround, administrators can do a "esxcfg-vmknic -d" to delete the virtual nic which is using the cached mac address. On recreation of that virtual nic it will have a VMW OUI MAC address.

1 comment:

  1. Great Post !
    Your link has provided me the much needed method to update my new MAC Address. Thanks for sharing.

    Regards
    Silvester Norman

    Change Mac Address

    ReplyDelete