Bug #23035: “DNS Settings” built-in technique doesn't work with systemd-resolved (notably Ubuntu 22.04 LTS) - Rudder - Issue Tracker

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Bug #23035

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“DNS Settings” built-in technique doesn't work with systemd-resolved (notably Ubuntu 22.04 LTS)

Added by Michel BOUISSOU 10 months ago. Updated 9 days ago.

Status:

New

Priority:

N/A

Assignee:

Category:

Techniques

Target version:

7.3.15

Pull Request:

Severity:

Major - prevents use of part of Rudder | no simple workaround

UX impact:

User visibility:

Getting started - demo | first install | Technique editor and level 1 Techniques

Effort required:

Priority:

Name check:

To do

Fix check:

To do

Regression:

Description

The “DNS Settings” built-in technique doesn't work for distros using systemd-resolved, which means a number of recent distros including Ubuntu 22.04 LTS.

root@lab_test_2_zgent7:/etc# lsb_release -d
Description: Ubuntu 22.04.2 LTS

When using systemd-resolved, resolv.conf is a symlink to a tmpfs file :

root@lab_test_2_zgent7:/etc# ll resolv.conf
lrwxrwxrwx 1 root root 39 Jun 16 02:07 resolv.conf -> ../run/systemd/resolve/stub-resolv.conf

This makes a directive based upon the “DNS Settings” built-in technique to fail.

With systemd-resolved, the DNS settings are supposed to be in
- /etc/systemd/resolved.conf
- /etc/systemd/resolved.conf.d/dns_servers.conf
etc.

It is also quite probable that the “DNS Settings” built-in technique wouldn't work properly along with other common DNS helper programs such as dsnmasq or resolvconf, that either manipulate the resolv.conf file or symlink it to virtual/temporary files under their own control.

The resolv.conf file is also frequently edited / modified by NetworkManager, common on RedHat like distros and default on many others.