Converting a bare-metal Debian instance to run in LXC

rsync -avz is enough to copy everything correctly. If converting the same host, you can run:

mkdir -p /var/lib/lxc/guestname/rootfs/
rsync --exclude=/var/lib/lxc -avz / /var/lib/lxc/guestname/rootfs/

Need to create an LXC configuration file at /var/lib/lxc/guestname/config, you can take it from some other container or template and modify accordingly.

WIP

The easiest way to do that is to move away the content of /etc/init.d

cd /var/lib/lxc/guestname/rootfs/etc/init.d/
mkdir _off
mv * _off/

Move back the stuff you are sure you actually need to run inside the container, plus some of the system stuff.

What can be moved back right away is:

cd _off/
mv halt procps rc rcS reboot ssh ../

WIP

The “physical” /etc/inittab is different, for instance it might not handle the poweroff signal from the host correctly (with errors such as described here).

Replace it with inittab taken from a native LXC template, which has been modified accordingly. For Debian 9 (Stretch) the working LXC /etc/inittab would be:

id:3:initdefault:
si::sysinit:/etc/init.d/rcS
l0:0:wait:/etc/init.d/rc 0
l1:1:wait:/etc/init.d/rc 1
l2:2:wait:/etc/init.d/rc 2
l3:3:wait:/etc/init.d/rc 3
l4:4:wait:/etc/init.d/rc 4
l5:5:wait:/etc/init.d/rc 5
l6:6:wait:/etc/init.d/rc 6
# Normally not reached, but fallthrough in case of emergency.
z6:6:respawn:/sbin/sulogin
1:2345:respawn:/sbin/getty 38400 console
#c1:12345:respawn:/sbin/getty 38400 tty1 linux
#c2:12345:respawn:/sbin/getty 38400 tty2 linux
#c3:12345:respawn:/sbin/getty 38400 tty3 linux
#c4:12345:respawn:/sbin/getty 38400 tty4 linux
p6::ctrlaltdel:/sbin/init 6
p0::powerfail:/sbin/init 0

WIP