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 ??
Why Network Manager do that with 7.6, I can't say but I am not happy witzh this update :-(.
Am Samstag, 15. Dezember 2018, 18:27:39 CET schrieb Gregory P. Ennis:
I have two units that are different users with desktop KVM hypervisors Centos 7 hosts. One had only one network card and it went through the migration from 7.5 to 7.6 without a problem. The other had three network cards and it became disabled with failed network connections. I had to rebuild the network and did so in the following manner.
#1. NetworkManager had been turned off. I turned NetworkManger from off to on so that it would create appropriate ifcfg-* files for three network cards after a reboot.
#2. I modified the appropriate ifcf-* files and created a new network bridge with one of the cards. After the update to 7.6 I was able to leave NetworkManager running as long as I had the appropriate ifcf-* file and the bridge set with “NM_CONTROLLED=no”. With Centos 7.5 I had to disable NetworkManager because it kept destroying the bridge even with the switch “NM_CONTROLLED=no”.
#3. Lastly I had to change the references to the new bridge in the KVM guests.
After this everything has worked like it did before the upgrade. My take on this is that kvm hypervisors that are set up with more than one nic card have the potential of having their network setup corrupted when the migration from 7.5 to 7.6 occurs. On a positive note NetworkManager now works with a network bridge with 7.6, but it did not work for me with 7.5.
Good Luck!!!
Greg