Comment 7 for bug 1574844

I did manage to reproduce the issue on 2.0 (master tip) on lxd w/ xenial, as suggested in #4, twice.

Unfortunately, I'm still looking for the root cause of this, and thus far it seems more related to lxd-bridge and/or cloud-init, rather than juju.

I can see a dhclient process appearing stuck in some of the containers (and only the init process is there, but otherwise the lxd container appears accessible and able to resolve DNS queries and reach the internet via the lxdbr0 nat settings).

For those containers (in both tests it was always 1 of 15 - and it was #12 in the first and #13 in the second test that had that issue). No observable differences otherwise in system config, logs, etc. between the container with the ipv6 address and all others).

It's interesting that with add-unit ubuntu -n 30 (after the deploy with -n 15) most of the new containers get stuck in pending with virtually only that dhclient process hanging, e.g. http://paste.ubuntu.com/16318617/

A possible workaround will be to restart the jujud process on the container appearing with an ipv6 address (NOTE: lxc list actually shows all containers RUNNING and having *both* IPv4 and IPv6 addresses). Will dig in some more..