Attached are some logs of a reproducer:

- juju deploy ubuntu (using MAAS as the provider and a node that has two NICs)
- juju deploy cs:trusty/ubuntu ubuntu-in-lxc --to lxc:N

ifconfig shows two interfaces up with Ip addresses


juju status:
environment: beretstack
machines:
  "0":
    agent-state: started
    agent-version: 1.20.12
    dns-name: maxwell.beretstack
    instance-id: /MAAS/api/1.0/nodes/node-2db80c2e-4b4a-11e4-ad24-a0b3cce4ecca/
    series: trusty
    hardware: arch=amd64 cpu-cores=4 mem=16384M
    state-server-member-status: has-vote
  "2":
    agent-state: started
    agent-version: 1.20.12
    dns-name: hawking.beretstack
    instance-id: /MAAS/api/1.0/nodes/node-1f0ed478-4b4a-11e4-a091-a0b3cce4ecca/
    series: trusty
    containers:
      2/lxc/0:
        agent-state: started
        agent-version: 1.20.12
        dns-name: 10.1.43.73
        instance-id: juju-machine-2-lxc-0
        series: trusty
        hardware: arch=amd64
    hardware: arch=amd64 cpu-cores=4 mem=16384M
services:
  ubuntu:
    charm: cs:trusty/ubuntu-0
    exposed: false
    units:
      ubuntu/0:
        agent-state: started
        agent-version: 1.20.12
        machine: "2"
        public-address: hawking.beretstack
  ubuntu-in-lxc:
    charm: cs:trusty/ubuntu-0
    exposed: false
    units:
      ubuntu-in-lxc/0:
        agent-state: started
        agent-version: 1.20.12
        machine: 2/lxc/0
        public-address: 10.1.43.73
networks:
  maas-br0:
    provider-id: maas-br0
    cidr: 10.1.0.0/16

ifconfig on ubuntu/0:
eth0      Link encap:Ethernet  HWaddr ec:a8:6b:fe:13:1b  
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:166826 errors:0 dropped:0 overruns:0 frame:0
          TX packets:76522 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:248259255 (248.2 MB)  TX bytes:6503166 (6.5 MB)
          Interrupt:20 Memory:f7d00000-f7d20000 

eth1      Link encap:Ethernet  HWaddr 00:23:55:2c:53:73  
          inet addr:10.1.35.93  Bcast:10.1.255.255  Mask:255.255.0.0
          inet6 addr: fe80::223:55ff:fe2c:5373/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:355 errors:0 dropped:0 overruns:0 frame:0
          TX packets:11 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:22459 (22.4 KB)  TX bytes:1762 (1.7 KB)

juju-br0  Link encap:Ethernet  HWaddr ec:a8:6b:fe:13:1b  
          inet addr:10.1.4.1  Bcast:10.1.255.255  Mask:255.255.0.0
          inet6 addr: fe80::eea8:6bff:fefe:131b/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:136290 errors:0 dropped:0 overruns:0 frame:0
          TX packets:70909 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:207406336 (207.4 MB)  TX bytes:5733540 (5.7 MB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:16 errors:0 dropped:0 overruns:0 frame:0
          TX packets:16 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:1360 (1.3 KB)  TX bytes:1360 (1.3 KB)

lxcbr0    Link encap:Ethernet  HWaddr de:89:89:11:a2:a5  
          inet addr:10.0.3.1  Bcast:10.0.3.255  Mask:255.255.255.0
          inet6 addr: fe80::dc89:89ff:fe11:a2a5/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:0 (0.0 B)  TX bytes:648 (648.0 B)

vethQ9C2XC Link encap:Ethernet  HWaddr fe:8c:ee:8d:f1:e9  
          inet6 addr: fe80::fc8c:eeff:fe8d:f1e9/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:3433 errors:0 dropped:0 overruns:0 frame:0
          TX packets:5992 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:277435 (277.4 KB)  TX bytes:8597263 (8.5 MB)


Logs attached.