Do not use non-core systemd

Posted Sep 24, 2025 10:56 UTC (Wed) by nim-nim (subscriber, #34454)
In reply to: Do not use non-core systemd by paulj
Parent article: An unstable Debian stable update

All those legacy config systems are completely outmatched by networkd. Whatever faults networkd maintainers have their config system blows the alternatives out of the water.

Do not use non-core systemd

Posted Sep 24, 2025 13:20 UTC (Wed) by joib (subscriber, #8541) [Link] (4 responses)

NetworkManager supports .ini style configuration files under /{etc,run}/NetworkManager/system-connections that you can push with ansible or other configuration management tools.

The support for old-school Redhat ifcfg- files has AFAIU been removed.

Do not use non-core systemd

Posted Sep 24, 2025 13:22 UTC (Wed) by joib (subscriber, #8541) [Link] (3 responses)

And indeed, the link the parent provided even contains a link to the manual for the newer style configuration files at https://www.networkmanager.dev/docs/api/latest/nm-setting...

Per that document, the keyfiles should support the full featureset of NetworkManager.

Do not use non-core systemd

Posted Sep 24, 2025 14:11 UTC (Wed) by nim-nim (subscriber, #34454) [Link] (2 responses)

The new format is a bit better but still not up to par of what you get with networkd.

Instead of all uppercase ifcfg variables you get all lowercase variables (with is arguably nicer but short of the tasteful capitalization networkd-side that improves legibility).

The keyfiles are structured but the doc is still unstructured registry-style.

Some properties use - as separator, others _

Networkmanager still writes optional properties with default values instead of limiting itself to things where a specific value has been set (the meaningful part of the configuration).

It very unfortunately names all wired connexions “Wired connexion X” with X some non deterministic value (à la Windows) instead of using something reliable such as the interface name (when in fact each “Wired connexion X” is locked to a specific interface). Even worse the naming is not in fact “Wired connexion X” but a localized string that will wreak havoc with automation (reminds me of all the awful XDG variables that most everyone ignores to hardcode simple consistent .config/.cache/etc everywhere)

And so on, I won’t even get into the advanced wildcard tricks networkd configuration inherits from systemd

Nothing is completely awful but it falls very short of the syntaxic care and maturity exhibited networkd-side.

Do not use non-core systemd

Posted Sep 24, 2025 16:25 UTC (Wed) by anselm (subscriber, #2796) [Link] (1 responses)

Nothing is completely awful but it falls very short of the syntaxic care and maturity exhibited networkd-side.

This, plus configuration files work the same across all of systemd. That level of consistency alone is worth the price of admission, compared to the traditional setup where every single component had its own unique configuration file format.

Do not use non-core systemd

Posted Sep 25, 2025 11:12 UTC (Thu) by kpfleming (subscriber, #23250) [Link]

Yes, the systemd-networkd configuration system is fantastic, and as you say the fact that it uses the same configuration mechanisms as the rest of the systemd means you get drop-in support for free, and in my mind that's worth the price of admission. The ability for a tool like Ansible to manage an underlying network interface with VLANs on top of it in separate (but additive) configuration files is really powerful.