Hi Tom, Mason, Anybody else...

Beowulf lxc 1:3.1.0+really3.0.3-8 amd64 is broken.

Simple test I picked up from the internet:

~# lxc-usernsexec
Failed to find subuid or subgid allocation

On a host configured for unprivileged containers it should drop you into unprivileged 'root' mode:

~#./lxc-usernsexec
# id
uid=0(root) gid=0(root) groups=0(root)
#ls -ld /root
drwx------ 29 nobody nogroup 4096 Oct 5 16:43 /root

The current lxc git HEAD works fine (see above, confirmation my host is correctly configured).
./init.lxc --version
4.0.0-devel

Considering what steps to take next...