Debian TC vote on init system coupling

Posted Feb 24, 2014 9:11 UTC (Mon) by peter-b (guest, #66996)
In reply to: Debian TC vote on init system coupling by jude-
Parent article: Debian TC vote on init system coupling

> Fortunately, the solution to achieving loose coupling without boxing ourselves into one init system is to stabilize the systemd APIs--namely, both the systemd-to-application and daemon-to-systemd-PID-1 APIs.

You will, I'm sure, be pleased to hear that both of the APIs you mention are covered by the systemd interface stability promise.

http://www.freedesktop.org/wiki/Software/systemd/Interfac...

Debian TC vote on init system coupling

Posted Feb 24, 2014 19:50 UTC (Mon) by jude- (guest, #95678) [Link] (4 responses)

I must have mis-spoken. When I said the "daemon-to-systemd-PID-1 API", I was referring to "the D-Bus interfaces of the main service daemon." This one is not covered by the stability promise, according to the article you provided. However, if it were stable, it would be possible to do things like make alternative implementations of logind or journald without dealing with a moving upstream target.

Debian TC vote on init system coupling

Posted Feb 24, 2014 20:07 UTC (Mon) by fandingo (guest, #67019) [Link] (3 responses)

I assume that you're talking about "Service bus API," although that is covered by the interface stability promise, so I'm not sure. Not that it matters though -- everything with type DBus is covered by the promise.

If you're instead referring to "reimplementable independently," I think you misunderstand what that is supposed to mean. Those interfaces are considered too specific to systemd and other systems should implement their own specific interfaces. Therefore, the systemd developers don't want to provide counsel for reimplementations. Nonetheless, the interfaces are stable, and the developers won't stop you.

Debian TC vote on init system coupling

Posted Feb 24, 2014 20:28 UTC (Mon) by jude- (guest, #95678) [Link] (2 responses)

No, not every D-Bus API is covered. The article you provided says as much--the D-Bus interfaces of the main service daemon are explicitly listed under the APIs that are NOT covered.

> Those interfaces are considered too specific to systemd and other systems should implement their own specific interfaces.

The same article says that these interfaces will eventually be stabilized. Presumably, so that development in the various systemd components can occur without breaking other components' functionality.

> Therefore, the systemd developers don't want to provide counsel for reimplementations.

I would never expect it from them.

Debian TC vote on init system coupling

Posted Feb 24, 2014 20:34 UTC (Mon) by fandingo (guest, #67019) [Link] (1 responses)

Are we looking at the same web page? I don't see anything with type DBus (column 2) and covered by interface stability promise "no" (column 3). Perhaps you can provide the examples I'm not seeing.

Even if we include non-DBus interfaces, every interface except "udev session switch ACL properties" is included in the interface stability promise.

Debian TC vote on init system coupling

Posted Feb 24, 2014 21:53 UTC (Mon) by jude- (guest, #95678) [Link]

Ah, I think we're looking at different articles (but on the same subject). You're looking at this one [1], right?

The one I was referring to was peter-b's article [2]. This one's the one that says that the D-Bus interfaces to the main daemon are not stable.

My apologies for the confusion.

[1] http://www.freedesktop.org/wiki/Software/systemd/Interfac...

[2] http://www.freedesktop.org/wiki/Software/systemd/Interfac...