How Not to Diff Config Files
While cleaning up some new config files under
/etc I accidentally deleted my
/etc/shadow file (aka password file). Oh shit. Note that I typed
meld as intended. Oh snap. Quick! Try to recover if
sudo will let me back in without a password:
$ sudo rm /etc/shadow /etc/shadow.pacnew $ sudo su - su: Authentication service cannot retrieve authentication info
Fail. Of course I can’t ssh back in as root because that’s locked down.
I prepared for a reboot and an adventure into single user mode. When suddenly my annoyance with Docker security returned to the rescue!
Docker and Backups to the Rescue
Why don’t I just mount my root file system and run a container as the root user with a volume mount of my broke file system?
$ docker run -v /:/wtf --rm -it ubuntu cp /wtf/mnt/backup/core/etc/shadow /wtf/etc/shadow
Done. What did I learn?
docker >> sudo
If I didn’t have a back-up I could just use the Docker container to write a new
Case for Backups
Who doesn’t keep back-ups these days? Back-ups primarily protect me from sketchy btrfs incidents with the second biggest offender being myself when armed with a keyboard. Somewhere at the end of the spectrum is hardware failure and physical loss.