I also experimented with adding additional NICs to LXC containers post deployment and that was not consistent either. I deployed 2 machines as described above with multiple NICs in the template before deployment and they consistently selected the first IP address from lxc-ls --fancy. But if I deployed the containers with only 1 NIC and then added additional NICs to the specific containers and rebooted them, they would obtain new IP addresses, but juju would sometimes report the previous address, i.e. it did not switch to a different address. However, some containers did switch to a different address on one particular host, and it also switched address to 2 different networks, meaning one physical machine had containers with the primary address reported by juju on the management network, data network and storage cluster network. The final deployment status output is shown here: http://pastebin.ubuntu.com/12887890/ Machine 1 and 2 had the template modified before deploying any containers. Machine 5 and 6 had the container configuration modified post deployment. 1/lxc/X and 2/lxc/X containers show addresses as 192.168.140.x 5/lxc/X containers show addresses as 192.168.140.x except 5/lxc/7 shows address as 192.168.160.90 6/lxc/X containers show addresses as 192.168.92.x which are correct. However, output from lxc-ls --fancy on each host always shows 192.168.140.x, then 192.168.160.x then 192.168.92.x. e.g.: juju ssh 5 sudo lxc-ls --fancy Warning: Permanently added '192.168.92.100' (ECDSA) to the list of known hosts. Warning: Permanently added '192.168.92.104' (ECDSA) to the list of known hosts. NAME STATE IPV4 IPV6 GROUPS AUTOSTART --------------------------------------------------------------------------------------------------------- juju-machine-5-lxc-0 RUNNING 192.168.140.24, 192.168.160.64, 192.168.92.72 - - YES juju-machine-5-lxc-1 RUNNING 192.168.140.27, 192.168.160.60, 192.168.92.75 - - YES juju-machine-5-lxc-10 RUNNING 192.168.140.87, 192.168.160.85, 192.168.92.93 - - YES juju-machine-5-lxc-11 RUNNING 192.168.140.23, 192.168.160.99, 192.168.92.94 - - YES juju-machine-5-lxc-2 RUNNING 192.168.140.88, 192.168.160.86, 192.168.92.76 - - YES juju-machine-5-lxc-3 RUNNING 192.168.140.90, 192.168.160.88, 192.168.92.78 - - YES juju-machine-5-lxc-4 RUNNING 192.168.140.84, 192.168.160.82, 192.168.92.81 - - YES juju-machine-5-lxc-5 RUNNING 192.168.140.85, 192.168.160.83, 192.168.92.82 - - YES juju-machine-5-lxc-6 RUNNING 192.168.140.89, 192.168.160.87, 192.168.92.84 - - YES juju-machine-5-lxc-7 RUNNING 192.168.140.21, 192.168.160.90, 192.168.92.86 - - YES juju-machine-5-lxc-8 RUNNING 192.168.140.86, 192.168.160.84, 192.168.92.88 - - YES juju-machine-5-lxc-9 RUNNING 192.168.140.60, 192.168.160.89, 192.168.92.90 - - YES juju-trusty-lxc-template STOPPED - - - NO Connection to 192.168.92.104 closed. Another possible issue, is that an extra IP address is also added to the output if a hacluster service is running and the virtual IP for the service is currently live on that container. For example: juju ssh 6 sudo lxc-ls --fancy Warning: Permanently added '192.168.92.100' (ECDSA) to the list of known hosts. Warning: Permanently added '192.168.92.105' (ECDSA) to the list of known hosts. NAME STATE IPV4 IPV6 GROUPS AUTOSTART ------------------------------------------------------------------------------------------------------------------------- juju-machine-6-lxc-0 RUNNING 192.168.140.97, 192.168.160.97, 192.168.92.73 - - YES juju-machine-6-lxc-1 RUNNING 192.168.140.98, 192.168.160.94, 192.168.92.74 - - YES juju-machine-6-lxc-10 RUNNING 192.168.140.25, 192.168.160.23, 192.168.92.92 - - YES juju-machine-6-lxc-11 RUNNING 192.168.140.99, 192.168.160.93, 192.168.92.95 - - YES juju-machine-6-lxc-2 RUNNING 192.168.140.94, 192.168.160.24, 192.168.92.77 - - YES juju-machine-6-lxc-3 RUNNING 192.168.140.93, 192.168.160.95, 192.168.92.79 - - YES juju-machine-6-lxc-4 RUNNING 192.168.140.96, 192.168.160.98, 192.168.92.80 - - YES juju-machine-6-lxc-5 RUNNING 192.168.140.91, 192.168.160.96, 192.168.92.83 - - YES juju-machine-6-lxc-6 RUNNING 192.168.140.26, 192.168.160.21, 192.168.92.85 - - YES juju-machine-6-lxc-7 RUNNING 192.168.140.92, 192.168.160.91, 192.168.92.246, 192.168.92.87 - - YES juju-machine-6-lxc-8 RUNNING 192.168.140.22, 192.168.160.22, 192.168.92.89 - - YES juju-machine-6-lxc-9 RUNNING 192.168.140.95, 192.168.160.92, 192.168.92.91 - - YES juju-trusty-lxc-template STOPPED - - - NO Connection to 192.168.92.105 closed. and: juju ssh 1 sudo lxc-ls --fancy Warning: Permanently added '192.168.92.100' (ECDSA) to the list of known hosts. Warning: Permanently added '192.168.92.101' (ECDSA) to the list of known hosts. NAME STATE IPV4 IPV6 GROUPS AUTOSTART ------------------------------------------------------------------------------------------------------------------------- juju-machine-1-lxc-1 RUNNING 192.168.140.66, 192.168.160.65, 192.168.92.243, 192.168.92.52 - - YES juju-machine-1-lxc-10 RUNNING 192.168.140.81, 192.168.160.79, 192.168.92.249, 192.168.92.69 - - YES juju-machine-1-lxc-11 RUNNING 192.168.140.82, 192.168.160.80, 192.168.92.250, 192.168.92.70 - - YES juju-machine-1-lxc-12 RUNNING 192.168.140.83, 192.168.160.81, 192.168.92.71 - - YES juju-machine-1-lxc-2 RUNNING 192.168.140.67, 192.168.160.66, 192.168.92.244, 192.168.92.56 - - YES juju-machine-1-lxc-3 RUNNING 192.168.140.68, 192.168.160.67, 192.168.92.242, 192.168.92.57 - - YES juju-machine-1-lxc-4 RUNNING 192.168.140.72, 192.168.160.70, 192.168.92.245, 192.168.92.60 - - YES juju-machine-1-lxc-5 RUNNING 192.168.140.73, 192.168.160.71, 192.168.92.61 - - YES juju-machine-1-lxc-6 RUNNING 192.168.140.75, 192.168.160.73, 192.168.92.248, 192.168.92.63 - - YES juju-machine-1-lxc-7 RUNNING 192.168.140.77, 192.168.160.75, 192.168.92.65 - - YES juju-machine-1-lxc-8 RUNNING 192.168.140.79, 192.168.160.77, 192.168.92.247, 192.168.92.67 - - YES juju-machine-1-lxc-9 RUNNING 192.168.140.80, 192.168.160.78, 192.168.92.68 - - YES juju-trusty-lxc-template STOPPED - - - NO Connection to 192.168.92.101 closed. However, of all these VIPs the only one that juju considers the primary IP is the one on container 6/lxc/7, which will break as soon as the VIP fails over to another container.