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ConsloeKit is the traditional mechanism for tracking user sessions on Linux. eLogind has similar functionality, but is based on systemd and "independentized".

What are the differences in their functionality/feature set? What are their pros and cons?

einpoklum
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2 Answers2

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Aside from the difference in maintainership pointed out by Ortomala Lokni (which I might add is only accurate for the original ConsoleKit, there is a fork called ConsoleKit2 which is actively maintained), there are a handful of mostly minor differences:

  • Configuration is handled differently. ConsoleKit has it's own configuration directory, while elogind uses the same configuration locations as systemd-logind.
  • Exact functionality is slightly different. I don't remember all of the specifics here, but it's mostly minor stuff that is not widely used.
  • The DBus API's are sufficiently different that most software needs to be built to use one or the other. I'm pretty sure most of this is just a change to the name of the DBus endpoints, but there might be a few other things too.
  • ConsoleKit either doesn't support cgroups, or only supports version one cgroups (if using ConsoleKit2), elogind only supports v2 cgroups.
  • Elogind actually needs cgroups, and in fact may have build problems on systems that do not have them configured the way it expects them to be.
einpoklum
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Austin Hemmelgarn
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  • Do you have to know systemd configuration generally to configure elogind, or is it just a different location? – einpoklum Apr 03 '18 at 19:31
  • The location is different, but the format is identical, but you don't have to understand systemd to configure it (it has it's own man page explaining all the settings for the config file). – Austin Hemmelgarn Apr 03 '18 at 19:36
  • So essentially I would prefer elogind if I wanted v2 cgroups? – einpoklum Apr 03 '18 at 19:40
  • @einpoklum Yes, though it may also be needed by some software (for example running GNOME without system). – Austin Hemmelgarn Apr 03 '18 at 20:10
  • What, GNOME _needs_ it to run? Why would a desktop environment have requirements regarding the daemon tracking users and groups? – einpoklum Apr 03 '18 at 20:35
  • I'm not quite sure, I just know that the GNOME display manager needs either elogind or systemd-logind. – Austin Hemmelgarn Apr 03 '18 at 21:50
  • Because it needs to know that a user is active or on the physical console to prevent/allow rebooting, suspend and other stuff like that which is the only reason why CK or logind exist – Bigon Apr 04 '18 at 06:44
  • @Bigon: That's not a reason to _need_ it, that's a reason to be able to use it if it's available. Also - if CK can do this like you suggest, why can't GNOME use it when it's installed rather than elogind? – einpoklum Apr 04 '18 at 10:29
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    @einpoklum Because the GNOME developers think CK is outdated (I mean it is unmaintained, right). GNOME used to use CK, and there was a very short period of time during which it could use CK or a logind interface, but they quickly got rid of CK support once the logind stuff worked. – Austin Hemmelgarn Apr 04 '18 at 11:17
  • Great answer, but there is one minor issue there: elogind supports cgroups v1, v2 and hybrid (aka /unified). cgroups support is mandatory, though. It won't have build problems (just tested on WSL), but won't run. – Yamakuzure Jun 20 '18 at 08:50
  • @Yamakuzure Based on my own experience with it, it fails to build correctly if you don't have the system configured as it expects (it will still build, it just won't run, which is still a build error IMO, and should be reported as such by the build system), and it doesn't work reliably with version 1 cgroups (I haven't tested with a hybrid configuration before though). – Austin Hemmelgarn Jun 20 '18 at 13:13
  • @AustinHemmelgarn Well, then we should discuss that on github.com/elogind/elogind/issues ; I am the elogind maintainer. ;-) And I have used elogind with legacy, hybrid and unified layout for months each. It just works, but the build system can not determine if your kernel has cgroup support enabled. If it has, and you have a cgroup controller like openrc, than elogind just detects which layout is used on startup. – Yamakuzure Jun 21 '18 at 14:59
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According to the official page of ConsoleKit:

ConsoleKit is currently not actively maintained.

and also:

The focus has shifted to the built-in seat/user/session management of Software/systemd called systemd-logind!

But if you want to use the features of systemd-logind without systemd, there is elogind for you. According to their official main page:

elogind is the systemd project's logind, extracted to a standalone package. It's designed for users who prefer a non-systemd init system, but still want to use popular software such as KDE/Wayland or GNOME that otherwise hard-depends on systemd.

Ortomala Lokni
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    Ok, not being maintained is a difference. But I was more interested in the differences in functionality. – einpoklum Apr 03 '18 at 17:32
  • ConsoleKit has been superseded by [ConsoleKit2](https://github.com/ConsoleKit2/ConsoleKit2) years ago. (Quote: "_ConsoleKit2 is a fork of ConsoleKit since it is no longer maintained._") – Yamakuzure Jun 21 '18 at 15:02