[rleigh]

daemontools, or respawn from inittab. There are a number of perfectly reasonable possibilities, of which these are just two.

But more generally, you didn't restart daemons if they crashed. Firstly, because they used to be written sufficiently well that they never crashed, because competent people wrote them. Secondly, because continually respawning and crashing does no one any good.

[astine]

Firstly, because they used to be written sufficiently well that they never crashed, because competent people wrote them.

If your deployment strategy depends on never having to run substandard software then you've already lost. Also, it just isn't true that older software was necessarily more reliable. It's just that when you found yourself maintaining poorly written software you just dealt with it through whatever means you had available. I remember having to use an IBM HSM implementation on AIX, something you would expect to just work because it was IBM software written for their own system on their own hardware, but in practice the filesystem kept invisibly crashing resulting in apparently corrupt files and I'd have to restart it every few minutes.

[rleigh]

The thing is, most Linux distributions ran services this way for well over two decades. The world did not end, and the number of problems we experienced in reality were negligible. If we wanted automatic service restart on failure, then there were facilities for doing so should we chose to avail ourselves of them.

If something is crashing and requires a restart, then doing it automatically is at best papering over a problem the admin should be investigating. It's a mitigation, rather than a solution, and might well cause more problems than it solves.

systemd isn't bringing anything particularly new or noteworthy to the table here.

[astine]

The thing is, most Linux distributions ran services this way for well over two decades.

So? That doesn't mean it was the best way to do things. Humanity existed for thousands of years without vaccines and still managed but that doesn't mean that disease wasn't a thing. Misbehaving services have always been a thing and they've always been a problem. I know because I've dealt with them. If you feel that other methods for dealing with misbehaving services are better, fair enough, but don't appeal to a mythical golden age where everybody wrote software without bugs.

[rleigh]

I'm not in any way appealing to a "mythical golden age". I'm simply pointing out that the whole Linux world ran this way for over two decades without this being a critical problem, or even a problem of particular note.

Not only that, but automated service restarting was configurable if desired, albeit not the default. If you wanted it, it was doable with ease. This is not a new feature which systemd brought to the table, it was already available.

[astine]

The sentence: Firstly, because they used to be written sufficiently well that they never crashed, because competent people wrote them. IS an appeal to a golden age. Because it's not true. People did write services that crashed and sysadmins had to work around them. I know this to be the case because I had to work with a particularly egregious example. Whether you think the older methods for managing them were better is one thing, but those problems existed and they caused lots of damage.