The question is basically in the title. usermod -v (--add-sub-uids) and usermod -w (--add-sub-gids) can be used to manipulate the subuid and subgid ranges for a user account, but there appears to be ...
Building unprivileged (userns) LXC container from scratch, by migrating a privileged container to be unprivileged
How can I build a privileged LXC (1.0.3) container (that part I know) and then migrate it successfully to be run unprivileged? That is, I'd like to debootstrap it myself or adjust the lxc-ubuntu ...