While trying to create a Gentoo container from stage 3, I ran into a error regarding permissions, when OpenRC tries start.
LXC error: lxc_drop_groups: 1475 Operation not permitted - Failed to drop supplimentary groups
OpenRC error: /etc/init.d/cgroups: line 92: /sys/fs/cgroup/cgroup.subtree_control: Permission denied
Solved issue by changing uid/gid, container was created from stage3, therefore the uid/gid of rootfs was 1000:1000 since i extracted it as 1000:1000, I added 0 1000 1 and 1 100000 65536. Still don’t know why it doesn’t work, but by changing rootfs ownership to 100000:100000, and removing 0 1000 1 and adding 0 100000 65536, the issue was solved.