Assumed DNS resolver bug under AlmaLinux 8

[rosasurfer]

See

installimage/functions.sh

Line 3000 in e15b5ea

echo -e "### ${COMPANY} installimage" > "$DNSRESOLVERFILE"

On a RHEL compatible OS /etc/resolv.conf is a file, not a symlink. On these OS installimage writes the DNS entries only to /etc/resolv.conf, not to the NetworkManager. If the NetworkManager reloads its profile it rewrites /etc/resolv.conf with the content of either /run/NetworkManager/resolv.conf or /run/NetworkManager/no-stub-resolv.conf.

Because installimage doesn't update those files the resulting /etc/resolv.conf is empty.
Effect: After first reload of the network profile DNS fails due to missing settings.

Observed on AlmaLinux 8.10 with provided OS images and installimage. From the code I conclude that other RHEL-compatible OS may be affected, too.

How to reproduce:

• run a standard install of AlmaLinux 8
• boot the system
• change host settings and reload the network, e.g. by hostnamectl set-hostname my.domain.tld
• now /etc/resolv.conf is wiped out and DNS fails

Snippet from /installimage.debug:

...
[14:33:48] # Setting up miscellaneous files
[14:33:48] :   --- /dev/null	2025-09-26 14:32:26.656481972 +0200
[14:33:48] :   +++ /installimage.Eps6S/hdd/etc/resolv.conf	2025-09-26 14:33:48.439918089 +0200
[14:33:48] :   @@ -0,0 +1,6 @@
[14:33:48] :   +### Hetzner Online GmbH installimage
[14:33:48] :   +# nameserver config
[14:33:48] :   +nameserver 185.12.64.1
[14:33:48] :   +nameserver 2a01:4ff:ff00::add:2
[14:33:48] :   +nameserver 185.12.64.2
[14:33:48] :   +nameserver 2a01:4ff:ff00::add:1
...

[asciiprod]

Thank you for your report. This currently affects Alma/Rocky 8 and 10 images which now also use NetworkManager, while the required DNSx entries are only generated for 9:
https://github.com/hetzneronline/installimage/blob/master/network_config.functions.sh#L315