Binsfeldius Cluster, Live Migration & VLAN tag pitfalls

As I only have three physical NIC’s in each node, which are all spoken for (see network design), I’m using a VLAN on the existing TTG DMZ network for the internal TTG LAN where my VM’s reside.

You can set a VLAN ID if you open the Hyper-V Manager and look under settings at the network adapter. Put a tickmark in the Enable virtual LAN identification and provide an ID number.

In my case I’m using the VLAN ID of #601 (Can be any number as long as it’s the same on all nodes).

I found that after a Live Migration of one of the VM’s I could not communicate with it and when I checked the VM has lost the VLAN ID !

When I tried a Live Migration of other VM’s some retained their VLAN ID and some lost the VLAN ID. As far as I could tell the only difference in configuring the VM’s is that for the ones that worked I’ve used Failover Cluster Manager and for the ones the didn’t work anymore I’ve used Hyper-V Manager to change the settings.

It’s good to emphasize is that Hyper-V manager is not cluster-aware and that all VM settings, for VM’s running on the cluster, need to be set either through Failover Cluster Manager or be refreshed on Failover Cluster Manager.

How to fix it

You can either A) make all the changes through Failover Cluster Manager or B) use Hyper-V Manager and let Failover Cluster Manager know that there has been a change on a VM or C) use SCVMM 2008R2 SP1 which is cluster-aware.

In this case the addition of a VLAN ID to the virtual NIC has been made through Hyper-V Manager so I need to open Failover Cluster Manager.

• Under Services and applications, double-click the VM
• In the middle-section of the window, right-click the VM and select More actions -> Refresh virtual machine configuration

Failover Cluster Manager will now incorporate all (external) changes. When it’s done you can choose to view a report.

That’s it. If you Live Migrate the VM now, the VLAN ID will go with it .