HOWTO Break into LXC

Oops, you locked yourself out of your LXC box! Now what?

Step 1: Have root on WOPR

You need root or sudo on the host, ie WOPR.

Step 2: Know your LXC ID

All LXC boxes have a numeric ID starting at 100.

Go find yours.

Step 3: lxc-attach

LXCs aren't VMs, they're containers. lxc-attach will let you run a command:

$ sudo lxc-attach -n 142 -- ls
bin  boot  dev	etc  home  lib	lib32  lib64  libx32  media  mnt  opt  proc  root  run	sbin  srv  sys	tmp  usr  var

Step 4: pwck

pwck syntax checks /etc/passwd and /etc/shadow.

If you edited them and broke them, this will save you.

# lxc-attach -n 142 -- pwck
user 'lp': directory '/var/spool/lpd' does not exist
user 'news': directory '/var/spool/news' does not exist
user 'uucp': directory '/var/spool/uucp' does not exist
user 'www-data': directory '/var/www' does not exist
user 'list': directory '/var/list' does not exist
user 'irc': directory '/run/ircd' does not exist
pwck: no changes

Step 5: passwd

passwd will reset your password.

# lxc-attach -n 103 -- passwd
New password: 
Retype new password: 
passwd: password updated successfully