Centos 7, kvm, virtualmin says "This system cannot be a KVM host : No bridge interfaces like br0 were found". This is after the installer script was run on brand new formatted system using --bridge-interface enp1s0f0 option since this is needed now. In the installer script console display, it shows:
Creating network bridge .. Created bridge br0 connected to enp1s0f0 .. already active
After a reboot, you lose connectivity. Other reports have same issue in the forums. So, I went to looking into this.... I had previously patched a Centos 7 cloudmin server to make it work with bridging. However, was not sure which line(s) were required.
A systemctl -l status network shows Connection activation failed: Connection enp1s0f0 is not available on the device enp1s0f0 at this time.
The solution, is to add this line in /etc/sysconfig/ifcfg-enp1s0f0:
After a systemctl stop and start of network service, all works fine.