Add a nesting.conf which can be included to support nesting containers (v2) Newer kernels have added a new restriction: if /proc or /sys on the host has files or non-empty directories which are over-mounted, and there is no /proc which fully visible, then it assumes there is a "security" reason for this. It prevents anyone in a non-initial user namespace from creating a new proc or sysfs mount. To work around this, this patch adds a new 'nesting.conf' which can be lxc.include'd from a container configuration file. It adds a non-overmounted mount of /proc and /sys under /dev/.lxc, so that the kernel can see that we're not trying to *hide* things like /proc/uptime. and /sys/devices/virtual/net. If the host adds this to the config file for container w1, then container w1 will support unprivileged child containers. The nesting.conf file also sets the apparmor profile to the with-nesting variant, since that is required anyway. This actually means that supporting nesting isn't really more work than it used to be, just different. Instead of adding lxc.aa_profile = lxc-container-default-with-nesting you now just need to lxc.include = /usr/share/lxc/config/nesting.conf (Look, fewer characters :) Finally, in order to maintain the current apparmor protections on proc and sys, we make /dev/.lxc/{proc,sys} non-read/writeable. We don't need to be able to use them, we're just showing the kernel what's what. Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com> Acked-by: Stéphane Graber <stgraber@ubuntu.com>