I attempted to install FusionPBX on a lxd container running jessie. I found that somewhere in the process dpkg or apt-get would hang forever. Rebooting didn't clear it up. I found a post on a Debian site that suggested it was a systemd problem. I ran the following command (on the host) and rebooted.
lxc config set guest 'security.privileged' true
It seems to have fixed the problem.
lxc config set guest 'security.privileged' true
It seems to have fixed the problem.