No DNS after upgrade Ubuntu 22.04 to 24.04

[vansens]

Hello support,
I am getting a DNS error after I upgraded Ubuntu from 22.04 to 24.04:

root@xxx:~# host releases.cloudron.io 127.0.0.1
;; communications error to 127.0.0.1#53: connection refused
;; communications error to 127.0.0.1#53: connection refused
;; no servers could be reached

This is a Hetzner VPS with netplan as follows:

root@xxx:~# cat /etc/netplan/50-cloud-init.yaml 
# This file is generated from information provided by the datasource.  Changes
# to it will not persist across an instance reboot.  To disable cloud-init's
# network configuration capabilities, write a file
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
# network: {config: disabled}
network:
    version: 2
    ethernets:
        eth0:
            addresses:
            - 2a01:xxx:xxxx:xxxx::1/64
            dhcp4: true
            gateway6: fe80::1
            match:
                macaddress: xx:00:00:xx:xx:xx
            set-name: eth0

resolvectl does not run:

root@xxx:~# resolvectl
Command 'resolvectl' not found, but can be installed with:
apt install systemd-resolved  # version 255.4-1ubuntu8.4, or
apt install systemd           # version 255.4-1ubuntu8.4

System info:

root@xxx:~# cloudron-support --troubleshoot
Vendor: Hetzner Product: vServer
Linux: 6.8.0-41-generic
Ubuntu: noble 24.04
Processor: Intel Xeon Processor (Skylake, IBRS)
BIOS NotSpecified  CPU @ 2.0GHz x 2
RAM: 3911724KB
Disk: /dev/sda1        15G
[OK]    node version is correct
[OK]    docker is running
[OK]    MySQL is running
[OK]    nginx is running
[OK]    dashboard cert is valid
[OK]    dashboard is reachable via loopback
[OK]    box v8.0.4 is running
[OK]    netplan is good
[WARN]  systemd-resolved is not in use. see 'systemctl status systemd-resolved'
grep: /etc/resolv.conf: No such file or directory
[WARN]  /etc/resolv.conf is not using systemd-resolved. it is missing the line 'nameserver 127.0.0.53'
[FAIL]  DNS is not resolving
;; communications error to ::1#53: connection refused
;; communications error to ::1#53: connection refused
;; communications error to 127.0.0.1#53: connection refused
;; no servers could be reached

root@xxx:~# systemctl status systemd-resolved
Unit systemd-resolved.service could not be found.
root@warkalla:~#

Kindly help

[vansens]

Fixed it myself. I had to

mv /etc/resolv.conf /etc/resolv.conf.orig

and then add a /etc/resolv.conf with content

nameserver 1.1.1.1
nameserver 8.8.8.8

[joseph]

@vansens in addition, if you want to use systemd-resolved (the ubuntu default), add the DNS in /etc/systemd/resolved.conf instead . The /etc/resolv.conf should be a symlink to /run/systemd/resolve/stub-resolv.conf (generated by resolved)

[lucifer1004]

@joseph I think it should be /etc/systemd/resolved.conf instead of /etc/systemd/resolve.conf.

[joseph]

@lucifer1004 thanks for the correction , will fix the original post!