hello Greg,
thanks for the answer, now I am not so alone ;-)
this Problem with the third NIC in a KVM Client is from Update to Update stronger. I mean on start the Installation "CentOS 7.0" we don't have this Problem!
without NetworkManager is run, on my system, I can't start the third Network- Card, I have always a LSB Error on the KVM-Clients ??
So now I found a workaround for my Problem :-(. (What are changed in the Network Configuration)
I set up the first and second NIC to "hostdev" (hardware) this is running also before the update and set “NM_CONTROLLED=no” to this NIC's.
The third is a Bridge controlled Interface now is running with NetworkManager as a static Interface with "PEERDNS=no" so I have my resolv.conf is not always change and NetworkManager don't create a new Interface with a DHCP config ??
To disable the fiddling of the tools with your /etc/resolv.conf, you can add this to disable it. Works for the init scripts and NetworkManager:
RESOLV_MODS="no"
Regards, Simon