Category Archives: ucs manger

UCS Blade unable to ping or connect to vCenter

Hi All,

I came across a strange issue where 2 blades was unable to ping I could get 2 ping and then Request time outs

Problem : 2 Servers( in the same chassis server 3,4 ) unable to ping their gateway. Ping drops are after 1-2 packets. We cannot ping/ssh to them from outside and they cannot be added to vCenter. Other blades in the same chassis are working ( 1,2)

Steps Taken :

  1. Confirmed that we do not have any IP conflicts
  2. Made sure that we do not use the same subnet anywhere else in the network
  3. Also checked and confirmed that the Mgmt(CIMC) subnet is different

ucs1

  1. Started a ping from inside a Host ( Server-3 ) to check if you are able to get to the gateway
  2. Checked vobd logs  to find if you can find any  entrie for duplicate ip/mac
  3. Checked the Mgmt Interface : vmk0
  4. It is connected to Port Group : Management Network  on VLAN ID, Check if we are  using the right vlan
  5. Found that the MAC Address of the vmk0 is same as vnic (vmnic0) : This is a known issue VMware KB article here. This is the vnic mac address of the service profile which is attached to the esx blade.
  6. Deleted and re-created the vmk0 interface
  7. Confirmed that the MAC Address has changed
  8. Started a continuous ping which work fine now
  9. Host can now be added to the vCenter

 

 

So let me go through of the process of how we found the duplicate mac address.

The vnic mac address was taken by vmknic  as you might know vmknic mad starts with 00:50:56 but in my case it was same as the mac address of vnic from the service profile. Read the rest of this entry

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