network-manager, bridge and vpn

Question

I have a shiny new system with Ubuntu 14.04 and I'm trying to get something configured which I think is reasonably simple:

• a bridge (br0) for KVM
• ability to use a VPN
• network-manager controlling it all

I've configured my br0 interface and the subinterface but no matter what I do, network-manager doesn't like it. It thinks br0 is unmanaged for some reason and never activates the connection.

I do like network-manager for the dnsmasq support when using a VPN - this is the only reason I haven't yet turfed it.

Things I've tried:

• enabling ifupdown and putting the configuration into /e/n/i
  • n-m almost works but assigns the /32 route to the default gateway to eth0 instead of br0
• putting everything in /e/n/i
  • n-m doesn't think there's a connection, so can't use VPN.
• getting rid of EVERYTHING except br0 and br0-eth0 (the subinterface) configurations
  • n-m still doesn't like - again it thinks br0 is unmanaged.
• adding/removing MAC addresses, changing names
  • no help

Has anyone yet got this working?

---

/etc/network/interfaces:

auto lo
iface lo inet loopback

.../system-connections/br0:

[connection]
id=br0
uuid=f2e53b47-234b-4d24-acf6-2c511ef0696c
type=bridge
timestamp=1409790457

[ipv6]
method=auto

[ipv4]
method=auto

[bridge]
interface-name=br0
stp=false

.../system-connections/br0-eth0:

[802-3-ethernet]
duplex=full

[connection]
id=br0-eth0
uuid=26a2a78b-296b-4dce-9e17-860c13956cb9
type=802-3-ethernet
timestamp=1409790457
master=f2e53b47-234b-4d24-acf6-2c511ef0696c
slave-type=bridge

---

Logs:

Sep  3 22:59:08 kronos NetworkManager[4321]: <info> Auto-activating connection 'br0-eth0'.
Sep  3 22:59:08 kronos NetworkManager[4321]: <debug> [1409799548.255597] [nm-manager.c:3026] nm_manager_activate_connection(): Activation of 'br0-eth0' requires master connection 'br0'
Sep  3 22:59:08 kronos NetworkManager[4321]: <info> Connection 'br0-eth0' auto-activation failed: (1) No compatible disconnected device found for master connection f2e53b47-234b-4d24-acf6-2c511ef0696c.
Sep  3 22:59:08 kronos NetworkManager[4321]: <debug> [1409799548.255610] [nm-agent-manager.c:698] next_generic(): (:1.56/org.freedesktop.nm-applet/1000) agent saving secrets for request 0x132b220/(null)
Sep  3 22:59:08 kronos NetworkManager[4321]: <debug> [1409799548.256800] [nm-agent-manager.c:1179] save_done_cb(): (:1.56/org.freedesktop.nm-applet/1000) agent saved secrets for request 0x132b220/(null)

○ → nmcli d
DEVICE     TYPE              STATE        
br0        bridge            unmanaged    
eth0       802-3-ethernet    disconnected 

○ → nmcli c
NAME                      UUID                                   TYPE              TIMESTAMP-REAL                    
br0                       f2e53b47-234b-4d24-acf6-2c511ef0696c   bridge            Wed 03 Sep 2014 08:27:37 PM EDT   
br0-eth0                  26a2a78b-296b-4dce-9e17-860c13956cb9   802-3-ethernet    Wed 03 Sep 2014 08:27:37 PM EDT