help with virt-manager, I think I need to reset settings?
 

I am running CentOS 7.2.

The basic thing here is that I am trying to get bridged networking going for KVM VMs so that the VMs will be able to get their own IP addresses and otherwise be fully reachable online.

In virt-manager, under Edit -> Connection Details, I went to Network Interfaces and clicked the + to add.

I picked bridge

In the bottom area I checked the box for my NIC, which is em1.

Somehow this broke things ... I think it fully deleted em1 somehow. It was missing entirely, meaning /etc/sysconfig/network-scripts/ifcfg-em1 was just plain gone. (And my system was offline)

I recreated the ifcfg-em1 and am online again. However, in the Network Interfaces panel, em1 is just gone from the virt-manager config. (See image 1)

If I try to add a device, I do not have the option of adding em1 back to virt-manager. (See image 2)

Is there a centralized location of the preferences for this system that I can regenerate? (I tried removing and reinstalling the relevant RPMs, but this did not affect the configuration.)

fwiw I set up my bridge outside virt-manager by editing/creating the ifcfg* files, and also turned off NetworkManager before creating the bridge.

Supposedly NM can create bridges now but I haven't tried recently. I recall virt-manager and NetworkManager both failed to create a working bridge for me.

I think at the least I need Network Manager, as we have a VPN that I basically need to be on all the time, and it's configured through NM.

I may poke at it some more.... or I may just install VirtualBox, which has the bridge option (at least seems to) right out of the box.

(But I hate how it slows down kernel updates)