[CentOS-virt] Network Problem KVM

Sat Jul 21 13:18:44 UTC 2018
Günther J. Niederwimmer <gjn at gjn.priv.at>

Hello List,

CentOS 7.5

I have a question about a KVM problem (??) with my Servers, I hope any have a 
answer. ;-)

My situation is, I have three server two identical motherboards and one 19" 

The problem is the configuration with the Bridge Interface!
On my motherboards I have configured a NIC for bridge, on the 19" Server I 
have the virbr0 from KVM configured.

All Server (motherboards) have a Intel I350 Ethernet Controller on Board, I 
configured this NIC's with the "igb" driver and in the KVM clients with with 
the "hostdev" option this two Interfaces are starting always correct.

But the "BRIGED" interfaces is the third Interface on all "servers", is 
starting only sometimes :-(.

I have to check all clients after a kernel update for correct networking?

The only way to have again correct working clients is to reboot or stop and 
start the clients sometimes three or four times and again.....

I have on all "Servers" 4-6 KVM Clients and this is a BIG problem for me!

Why is this possible (?), is my configuration broken or is a driver broken 

thanks for a answer and help is possible,

mit freundlichen Grüssen / best regards,

  Günther J. Niederwimmer