[rkrzr]

This is indeed an issue in practice:

I recently wanted to use the "systemd-journal-gatewayd" component in Ubuntu 16.04, which ships with systemd v229. Yet, the feature I needed was only available in v231.

Although I'm only interested in a newer version of "systemd-journal-gatewayd" there is no way to upgrade just this one component, it seems.

[traviscj]

I don't get this. How do you know that the v231 for that component will work with older versions of everything else? If you do, why not just compile it yourself? If you don't like that, why not upgrade everything to v231?

[Elhana]

That is the point - you often can't just recompile journald part, because it is tied to systemd interfaces and you might not be able to easily upgrade systemd, because it is a production system you can't simply reboot like your home server. The only way to do that is backporting specific patches to the older version.

If it were a separate component, it would have a bunch of ifdefs covering several versions of systemd, possibly with some features disabled if older version doesn't support it. However, that somewhat increases code complexity for developers and systemd devs refuse to do that.

That is the point of 'monolithic' criticism - despite being many binaries, you can't easily just build single one and make that work.

[ripdog]

There is systemctl reexec, so can't you upgrade systemd without a reboot using that?