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I try to repair an broken Ubunu 14.04 with chroot. What I did, is to boot Ubuntu from USB mounted the original system that has to be repaired and changed to this system with chroot:

sudo mount /dev/sdXY /mnt 
sudo mount -o bind /dev /mnt/dev 
sudo mount -o bind /sys /mnt/sys 
sudo mount -t proc /proc /mnt/proc 
sudo cp /proc/mounts /mnt/etc/mtab 
sudo chroot /mnt /bin/bash

That worked fine, but in chroot environment I don't have access to the internet, so apt isn't able to resolve hostnames. What am I supposed to do? 

ping www.askubuntu.com

does not work either.

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3
  • I think my command should be for d in dev sys run proc; do sudo mount -o bind /$d /mnt/$d ; done
    – Avinash Raj
    May 19, 2014 at 16:24
  • try and get back to me soon :-)
    – Avinash Raj
    May 19, 2014 at 16:27
  • Seems to work, but I am not quite sure, because it my be an other reason making it work. Thank you anyway!
    – user5950
    May 19, 2014 at 16:54

1 Answer 1

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37

On newer Ubuntu systems, name resolution is handled by the resolvconf service, and /etc/resolv.conf is a symbolic link to /run/resolvconf/resolv.conf. You can either add a bind mount to the /run filesystem along with your other bind mounts before executing the chroot command

sudo mount -o bind /run /mnt/run

so that the chroot system picks up the host system's DNS settings or, once you're in the chrooted system, temporarily create a static /etc/resolv.conf with nameserver(s) of your choice e.g.

echo 'nameserver 8.8.4.4' | sudo tee -a /etc/resolv.conf
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  • 2
    What are "newer Ubuntu systems"; in other words since which version is name resolution handled by resolvconf?
    – Pro Backup
    Aug 11, 2014 at 16:04
  • @ProBackup at least from 12.04 I think, although it may have been backported - see DNS in Ubuntu 12.04
    – steeldriver
    Aug 11, 2014 at 16:12
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    doing sudo mount --bind /run /mnt/run worked for me chrooting into a botched 17.10 upgrade. Thanks for the answer!
    – labyrinth
    Nov 17, 2017 at 1:02
  • Is there a permanent solution?
    – birgersp
    Aug 28, 2018 at 15:58
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    It’s probably a bit defeating the purpose of chroot if you bind the whole /run directory with a lot of sockets, so probably binding only the needed sockets is a better idea (resolvconf, maybe nscd and syslog)
    – eckes
    Mar 19, 2019 at 9:23

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