[vezzy-fnord]

The problem with this straightforward thesis is twofold: firstly, distribution developers did not have any coherent position on the disadvantages of sysvinit or initscripts; secondly, the problem was mostly an iatrogenic one, as the very attempts to 'solve' or 'reform' it made things even less sustainable.

When it comes to Upstart, it was almost never used except as a wrapper around initscripts. Effectively you booted from Upstart which greedily synthesized all of its 'events' on startup that in turn triggered initscripts, which brought some degree of parallelism and that was about it. The reverse-dependency 'start/stop on' model was too esoteric, and Upstart's state machine brittle. Hilariously enough, the only system to actually use Upstart to its fullest (still does) is ChromeOS.

Prior to systemd and Upstart, as I discuss in chapter 1, distro developers either simply added various preprocessors for initscripts to introduce dependency headers, or they had these vague hunches of 'waiting for Godot' that we could either replace init entirely with D-Bus, put D-Bus interfaces in initscripts, or some other roundabout way that involved grafting D-Bus. Much of this was owing to the 'irrational exuberance' of Linux developers wanting to hotplug the world after 2003-4, but it always remains an on-and-off effort with the people behind it never certain what they want.

Indeed, besides grunt work of optimizing initscripts, I point out that as late as 2009 distros like Debian were still very concerned about LSB-compliance, and that even when they were willing to adopt a new fancy event-driven init like Upstart, it was conditional on reusing tools like insserv to parse LSB headers, and on incorporating initscripts for service management. Also the entire bizarre diversion that the Debian group had of using a Perl script to generate initscripts.

So far as I know, the daemontools approach was never influential. The available dichotomy was between putting lipstick on a pig, and utopian dreaming.

The paradox remains: how can we trust that the same people who did the Wrong Thing so persistently then suddenly turned out and did the Right Thing like they hit jackpot? If anything, 'jackpot' is the right analogy -- it was a fluke. And the same integration failures that were had with sysvinit have now been shifted into wrestling systemd's job model.

"Unification" was a folly, as the distro is still the place that gets its finger pointed at if upstream can't deliver, and upstream insists it's "just" offering a bunch of "modular tools," which ironically was supposed to be the problem to be addressed! Besides, there is still a whole world of Linux devices out there running Busybox, musl, OpenWrt, etc. that are outside the systemd bubble. Or think of all the container images running Alpine (which is also the basis of postmarketOS). Linux is still the same bazaar it always logically must be, but with a new class distinction added to the mix.

[cycloptic]

The distro has historically always been the place that gets pointed at because they are the ones who distribute to end users. No system-level component is going to change this, ever.

I am also confused why you're complaining about the job model and all its churn and conceptual problems when the whole point is that systemd was offering to handle that for the distros, which is exactly what they did and are continuing to do now. You can claim they are doing a bad job (which is probably true in some sense because of the impossibly large scope of the task) but the previous alternative was that nothing was being done about it at all. Which you did acknowledge, but then you went back to the same criticism as before. Why? It seems obvious to me that the gritty technical aspects and/or perceptions and fears about some kind of false dichotomy are not what could have ever influenced this kind of decision. Nobody else is invested enough in it for that to have happened.

The other reality I've seen is that there is no standard way to actually implement a daemon. Nobody does it in quite the same way and using things like daemon(3) don't help. So you can choose to A. patch all your daemons, or B. you can attempt to simplify the task by writing more tooling. Every single Linux distro I've seen, when given the choice, has chosen option B. So really, I don't see anything here that is surprising or farcical at all.

[vezzy-fnord]

The 'job model' is the wrong abstraction, as is the unit concept which tries to reduce things that have irreducible differences. I'm also rather amused how you're conceding that they're doing a "bad job," but still shrug it off as better than nothing. If you're offering a mediocre solution to an "impossibly large scope" of a task, then you ought to rethink things. Even then, a poorly implemented feature can be worse than none at all.

So far as prior art is concerned, see my old post: https://blog.darknedgy.net/technology/2015/09/05/0/

I would also point out OpenWrt's procd as an example of how to have hotplug-capable service management at a fraction of the complexity: https://openwrt.org/docs/techref/procd

Now, this rethinking did indeed come with HAL, when the idea of a master daemon and ad-hoc service manager reacting to hardware state changes was unanimously rejected by the Linux patriciate as wrong. Perhaps with systemd they will one day reach the same epiphany for system and user services. Either way, I'm not terribly personally invested in this anymore -- I just figured I'd wrap my thoughts up on an issue that occupied a good deal of my time years ago.

EDIT: As to B, the problem of process supervision and having an idiomatic way of daemonizing has been solved for a long time: https://jdebp.eu/FGA/unix-daemon-design-mistakes-to-avoid.ht...

[cycloptic]

The entire purpose of designing models is to reduce things that have irreducible differences and then tell people to shut up and deal with it. There is nothing else there. What is it exactly that you think IT gets paid to do other than this? We have finite time on this planet.

Also, things are constantly being rethought. That is quite literally what the churn encompasses. You can't complain about this while asking for it at the same time. I have seen all these lists of other init systems and while they are interesting, they are completely missing where the actual discussions are happening and what is actually being discussed. The core problem has already moved to a different area and that's why it really doesn't matter if they are doing a bad job. I can see you hinting at this in your article but it's not good to dwell so much on things that happened in the past and are already history. I am very grateful that you actually quoted all your sources though, so thank you for that.

The comparison of init to HAL seems not relevant to me; if anything that has made it obvious that they had the right idea but it was in the wrong place, and that init was the right place to put this type of logic after all. Adding to that it also seems very unlikely that the kernel developers will change their position on the responsibilities of an init any time soon.

And about the idiomatic way to daemonize, nobody follows those guides. Nobody. Seriously. It's a complete clusterfuck and writing more guides doesn't help either. There are an absurd number of programs out there that still use pidfiles. Go and do a search on github for "pidfile" and be horrified.

[vezzy-fnord]

All models are wrong, some are useful, others not so much. There's no need to treat me with these banalities. The job model ought to have died with Upstart. It did not. Oh well.

> The core problem has already moved to a different area and that's why it really doesn't matter if they are doing a bad job.

Yes, I agree.

Still, the losers of history deserve their voice, too.

"Nobody" is a significant overstatement. A lot of (certainly not all) daemons that used to only support double-forking and PID files were fixed in the wake of daemontools. systemd and other init systems benefited from this work when they appeared. Still, PID files are subject to TOCTTOU regardless of what you use, so that's a given.

[cycloptic]

Sorry for the glibness I am just really bored with these complaints, it really feels like the same old bikeshedding. As far as I know there is no way to make a transactional state machine without having the concept of a single, reordable work unit. Daemontools did not solve this or present a different model that was more workable. For every developer that rewrote their daemon to get rid of forking, we got more new developers with outdated learning material coming over who expected services to work like they did on some other crazy environment like Microsoft Windows.

I don't particularly care about who was a "winner" or a "loser" either. In general you cannot get away from TOCTOU on Unix without taking extreme care and avoiding things that would seem reasonable, like storing filenames in other files or using the "kill" command. In practical use I have seen no inits that make any concerned effort to solve these issues at all. That is a situation in which we all lose.

[vezzy-fnord]

> As far as I know there is no way to make a transactional state machine without having the concept of a single, reordable work unit.

You're basically taking systemd's architecture as an axiomatic premise, so no surprise your conclusion is obvious. I reject the premise, and the fruits of it I go into detail in chapter 3.

For the record I am mostly a Unix-hater, so your complaints about Unix are things I agree with. systemd, however, is simply more New Jersey design with unwarranted pretensions.

systemd, in a way, is exactly the init system that a community as infantile and disordered as Linux rightfully deserves. May they enjoy it.

I'll leave things at that.