No DNS resolution in chroot + qemu

Support Network
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#1

Hi, I’m trying to chroot into a Raspbian image, but there’s not domain name resolution inside the chroot.

  • I’m 100% sure to have the correct bind mounts
  • the correct /etc/resolv.conf (i tried several)
  • ping an IP works (ipv4, ipv6)
  • I tried adding a domain in /etc/hosts, and resolution works for this domain only.
  • I tried using systemd-nspawn instead of chroot as it’s supposed to be more solid.

Still, I get :

root@latitude5400:~# ping google.com
ping: google.com: Temporary failure in name resolution

Do you have any idea ?
Thanks !

#2

Hi and welcome to the forum :+1:

Check:

  • systemctl status systemd-resolved
  • resolvectl status
#3

Thanks :smiley:

Here are the status :

~ ❯❯❯ resolvectl status
Failed to get global data: Unit dbus-org.freedesktop.resolve1.service not found.
~ ❯❯❯ systemctl status systemd-resolved
● systemd-resolved.service - Network Name Resolution
     Loaded: loaded (/usr/lib/systemd/system/systemd-resolved.service; disabled; vendor preset: enabled)
     Active: inactive (dead)
       Docs: man:systemd-resolved.service(8)
             man:org.freedesktop.resolve1(5)
             https://www.freedesktop.org/wiki/Software/systemd/writing-network-configuration-managers
             https://www.freedesktop.org/wiki/Software/systemd/writing-resolver-clients

Looks like none are used. That’s weird, I never customized the DNS config and I installed Manjaro less than 2 months ago.

#4

Yea commands like ping need that service enabled (and started)…
But the service needs manual intervention for it’s correct operation maybe that’s why they didn’t enable it by default.
See: systemd-resolved.service

In short you just need to symbolic link /etc/resolv.conf -> /run/systemd/resolve/stub-resolv.conf before starting it :wink:

#5

Just to be sure : ping and such WORK in the host. They just don’t work in the chroot/systemd-nspawn “guest”.
I tried symlinking the resolv.conf and starting systemd-resolved, that did not help :frowning:

#6

I have the exact same issue as @Salamandar: network and DNS work on host, only network works in chroot (DNS do not work).

I think the issue is that Manjaro uses NetworkManager and not resolvctl to handle DNS by default, whereas Raspian/Ubuntu uses resolvctl. I assume the incompatibility is causing the issue, but I haven’t found a solution yet.

#7

Hi,

I had the same issue and found a solution.

To have dns resolving to work inside the chroot you need to mount /run into your chroot.
And start the systemd-resolved.service service.

On your host system mount the required filesystems

# mount -t proc none /mnt/chroot/proc
# mount -t sysfs none /mnt/chroot/sys
# mount -o bind /dev /mnt/chroot/dev
# mount -o bind /dev/pts /mnt/chroot/dev/pts
# mount -o bind /run /mnt/chroot/run/

Start the systemd-resolved.service

# systemctl start systemd-resolved.service

Go into the chroot

LANG=C chroot /mnt/chroot/

Test it

# LANG=C chroot /mnt/chroot/
[root@vicky /]# uname -a
Linux vicky 5.12.19-hardened1-1-hardened #1 SMP PREEMPT Tue, 20 Jul 2021 17:48:41 +0000 aarch64 GNU/Linux
[root@vicky /]# ping manjaro.org
PING manjaro.org (116.203.91.91) 56(84) bytes of data.
64 bytes from mail.manjaro.org (116.203.91.91): icmp_seq=1 ttl=53 time=30.2 ms

Hope this helps…

–
staf

1 Like
#8

try running systemd-nspawn with --resolv-conf=copy-host.
That works in our ARM tools.

#9