I verified that * commenting out lxc.init.cmd and * putting lxc.mount.auto = cgroup:rw:force AT THE LAST LINE of /var/lib/lxc/autopkgtest-unstable-amd64/confiig
allowed successfull autopkgtest of systemd on a host both with unified and hybrid hierarchy, WITHOUT changing /var/lib/lxc/autopkgtest-unstable-amd64/confiig. A problem is that putting lxc.mount.auto = cgroup:rw:force in /etc/lxc/default.conf will not work, because the content of /etc/lxc/default.conf is overwritten by lxc.include = /usr/share/lxc/config/debian.conf loaded later in autopkgtest-unstable-amd64/confiig. On the other hand > lxc.mount.auto = cgroup:rw:force proc:mixed sys:mixed > in /usr/share/lxc/config/common.conf. should work. Ryutaroh