So to put it quite bluntly I am no vSphere master. Give me a network DMZ design and let me loose. Enterprise network edge? Ace. BGP? No worries. I am learning my doing (see breaking) my lab in Singapore at the moment.

The Situation

When you configure a Distributed Virtual Switch under vCenter there is configuration stored on vCenter and the vSphere host. Well I destroyed my vCenter and decided I would seize the vSphere host under a new vCenter. Problem was that the vNIC0 was still associated to an orphaned DVS.

vNIC0 was attached to Mgt_DVS_ which caused a few headaches. This wouldn’t normally be an issue as I have more than one NIC uplinked to a network but this environment is nested on OpenStack.

After enabling MAC learning on the OVS and removing the Neutron Security Group I jumped into the vSphere CLI.

The command esxcfg-vswitch -l 

[[email protected]:~] esxcfg-vswitch -l
Switch Name      Num Ports   Used Ports  Configured Ports  MTU     Uplinks
vSwitch0         1536        4           128               1500    vmnic2

  PortGroup Name        VLAN ID  Used Ports  Uplinks
  VM Network            0        0           vmnic2
  Management Network    0        1           vmnic2

DVS Name         Num Ports   Used Ports  Configured Ports  MTU     Uplinks
Mgt_DVS          1536        4           512               1500    vmnic0

  DVPort ID           In Use      Client
  8                   1           vmnic0

I need to free the vmNIC0 from the DVS. The command required for this:

esxcfg-vswitch -Q vmnic0 -V 8 Mgt_DVS

This command will identify vmnic0 with the DVPort ID of 8 on the Mgt_DVS and remove it. I will confirm this once more.

[[email protected]:~] esxcfg-vswitch -l
Switch Name      Num Ports   Used Ports  Configured Ports  MTU     Uplinks
vSwitch0         1536        4           128               1500    vmnic2

  PortGroup Name        VLAN ID  Used Ports  Uplinks
  VM Network            0        0           vmnic2
  Management Network    0        1           vmnic2

DVS Name         Num Ports   Used Ports  Configured Ports  MTU     Uplinks
Mgt_DVS          1536        1           512               1500

  DVPort ID           In Use      Client
  8                   0
  7                   0

Now that the vNIC is removed from the DVS I can reuse it where I desire.

Learning by doing

Whilst there is all the information out there you don’t learn as quickly or as efficiently as when you break something yourself. Troubleshooting is a great way of find out what went wrong, how to fix it, and to see what your actions impact.