VM disconnects from network after VMotion

[prime]

Has anyone seen this problem? I put a ESX 3.5 host into maintenance mode, let the VMs move to other hosts, and then two of the moved virtual machines had their virtual network adapter disconnected. I had to edit the VM settings, choose network adapter, and click the checkbox for Connected to reconnect them to the network. This morning I put a different host running ESX 4.0 into maintenance mode and had the same problem with another, different VM.

[dilpreet]

Do you have the same VM network on both hosts? Are both networks accessible?

vMotion will just verify if the VM network in question exists at the destination ESX host, it will not check that that host in fact has connectivity to that network. So if connectivity is down on a particular host we might still migrate to it, even though the network is not currently accessible.

[prime]

Yes, everything is identical between all hosts. Both networks are accessible. These VMs have vmotioned between these hosts in the past with no problem. I just had two more VMs disconnect after vmotioning yesterday afternoon.

[jbreto2]

I am having the problem.

All the hosts are ESX 4.0 Update 2 and for some reason that I can't explain 2 virtual machines network connection won't stay connected if located on on particular host. If I VMotion the virtual machine to another host in cluster the network connection becomes available. The 2 virtual machines have a flexible network adapter.

I will keep you posted if I find a solution

[Eelm]

Hello,

as anyone of you found a solution ? We are experiencing the same issue and I am unable to figure out what is wrong. For some reasons when I put a host in maintenance mode, some of the migrated vm get their network disconnected and I have to manually go and edit the settings of each vm to check back the connected box of each network adapter.

Thanks a lot for any answer or help you can provide.

Seb

[dgourlay]

Are the hosts connected to the same network switch? If they are connected to separate switches it is possible that the VLAN used for vMotion is on both switches but the VLAN you are attempting to use for the vNIC is not configured on one of the switches and thus it will not pass it on the trunk interface.

(most vendors switches require the VLANs to be manually configured via the switch CLI in orer to pass traffic from one 802.1q trunk to another...)

dg

[Rubeck]

It sounds like a vSwitch running out of available ports... and then disconnects the vNIC.

/Rubeck