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I've just read that it uses a lot of Linux-specific things, but are there features that inherently can't be ported to BSD? And are those features absolutely cri

by avar 11y ago

I've just read that it uses a lot of Linux-specific things, but are there features that inherently can't be ported to BSD? And are those features absolutely critical to running it at all? What I've read sounds more like "we're focusing on Linux, and won't be porting it" rather than "this software is inherently Linux-only, and can't be ported". I daresay coming up with a shimmy layer to port it to BSD is probably less effort than completely rewriting it.

JoshTriplett 11y ago
I like systemd, but I do think it'd be far easier to write a compatible system for FreeBSD (or enhance the FreeBSD kernel to provide the necessary features) than to port it. For instance, systemd fundamentally depends on cgroups; without an equivalent mechanism, it won't work at all. The same goes for dozens of other features. The necessary functionality doesn't exist in POSIX; rather than attempting to write a half-functional "portable" implementation, it would make more sense to embrace the FreeBSD kernel, use its features as appropriate, and build a full-featured init system specifically for FreeBSD. In an ideal world, that system would provide all the features of systemd. (Note, for instance, that I said "FreeBSD", not "BSD"; portability is not worth trying to enhance 3-4 kernels to support the features you need, or sinking to the lowest common denominator.)
Touche 11y ago
The systemd developers do no care about BSD, full stop. In fact they believe that portability is a negative attribute that leads to compromises and that by coupling everything together systemd can make Linux a better user experience and more like the popular proprietary OSes.
JdeBP 11y ago
> I daresay coming up with a shimmy layer to port [systemd] to BSD is probably less effort than completely rewriting it. The self-styled "uselessd guy" is right here on this very page. Xe attempted making systemd portable. The project is now dead. The experiences of the "uselessd guy" and of Ian Sutton, who is the bloke who did the work trying to make a systemd-logind for OpenBSD, are worth hearing. * https://news.ycombinator.com/item?id=10176275 https://news.ycombinator.com/item?id=10176275 * http://homepage.ntlworld.com./jonathan.deboynepollard/FGA/debian-systemd-packaging-hoo-hah.html#systemBSD http://homepage.ntlworld.com./jonathan.deboynepollard/FGA/de...
Sanddancer 11y ago
They've expressly said that they won't accept any patches that will make it portable -- "We do not consider it feasible to port systemd to other Unixes (let alone non-Unix operating systems) and will not accept patches for systemd implementing any such portability" [1]. A lot of the issues come down to how Linux does namespacing, and how there's a lot of code that's hard-wired to require it. So any port would be a fork by near definition. [1] http://www.freedesktop.org/wiki/Software/systemd/InterfacePortabilityAndStabilityChart/ http://www.freedesktop.org/wiki/Software/systemd/InterfacePo...

by avar 11y ago

JoshTriplett 11y ago

I like systemd, but I do think it'd be far easier to write a compatible system for FreeBSD (or enhance the FreeBSD kernel to provide the necessary features) than to port it. For instance, systemd fundamentally depends on cgroups; without an equivalent mechanism, it won't work at all. The same goes for dozens of other features. The necessary functionality doesn't exist in POSIX; rather than attempting to write a half-functional "portable" implementation, it would make more sense to embrace the FreeBSD kernel, use its features as appropriate, and build a full-featured init system specifically for FreeBSD. In an ideal world, that system would provide all the features of systemd. (Note, for instance, that I said "FreeBSD", not "BSD"; portability is not worth trying to enhance 3-4 kernels to support the features you need, or sinking to the lowest common denominator.)

Touche 11y ago

The systemd developers do no care about BSD, full stop. In fact they believe that portability is a negative attribute that leads to compromises and that by coupling everything together systemd can make Linux a better user experience and more like the popular proprietary OSes.

JdeBP 11y ago

> I daresay coming up with a shimmy layer to port [systemd] to BSD is probably less effort than completely rewriting it. The self-styled "uselessd guy" is right here on this very page. Xe attempted making systemd portable. The project is now dead. The experiences of the "uselessd guy" and of Ian Sutton, who is the bloke who did the work trying to make a systemd-logind for OpenBSD, are worth hearing. * https://news.ycombinator.com/item?id=10176275 https://news.ycombinator.com/item?id=10176275 * http://homepage.ntlworld.com./jonathan.deboynepollard/FGA/debian-systemd-packaging-hoo-hah.html#systemBSD http://homepage.ntlworld.com./jonathan.deboynepollard/FGA/de...

Sanddancer 11y ago

They've expressly said that they won't accept any patches that will make it portable -- "We do not consider it feasible to port systemd to other Unixes (let alone non-Unix operating systems) and will not accept patches for systemd implementing any such portability" [1]. A lot of the issues come down to how Linux does namespacing, and how there's a lot of code that's hard-wired to require it. So any port would be a fork by near definition. [1] http://www.freedesktop.org/wiki/Software/systemd/InterfacePortabilityAndStabilityChart/ http://www.freedesktop.org/wiki/Software/systemd/InterfacePo...