Migration from 4.1 to 4.2: VM starts but no network



I had to migrate UCS 4.1 to 4.2
I did stop the windows 2003 VM before upgrading. Still I was warned that migration from 4.1 to 4.2 updates QEMU and may generate problems with VM.
However, as I had to migrate, I did force update42/qemu to yes and completed upgrade.
After the upgrade, I restarted my VM. So far so good but server was not accessing the LAN :frowning:

checking UCS network settings, I noticed that eth0 was set to start = true and was designed as default interface instead of br0

I changed settings according to this link:
but server still can’t get any IP from (external) DHCP server thus can’t access the LAN.

Odd point: DHCP server receives requeste from the right MAC address (the one defined at VM level).
It offers IP but it looks like IP is not accepted.
Even if setting, on Win server, manual IP, it doesn’t work.

One additional point: network interface is defined as “VirtIO”

Do you have any idea? Where shall I investigate? :thinking:


Bringing some additional inputs: if I add realtek network interface to my VM, it works, with this interface.
I can get IP from DHCP then access the LAN.
So problem is with VirtIO…
I’ll try to update this driver and post the result here.



if I get your problem right, you used the paravirtualized network interface for Windows? Did you try updating the KVM drivers for Windows using the shipped KVM driver ISO file?

Timo Denissen


Yes, your understanding is correct.
I’ve built VM with virtIO for both storage and network. So far it worked well while running UCS 4.1
I can’t update driver right now but will do it asap and post the result here.

Regarding driver version, I installed it using driver from RedHat. quite old version, from 2012 as far as I remember.
I’ll crosscheck this too.