The Grumpy Editor's guide to surviving the systemd debate

The Grumpy Editor's guide to surviving the systemd debate

My preferences is generally towards having a simple engine

“Simple” is generally a good idea, but there is such a thing as “too simple”. The sysvinit “engine” is really too simple for what it needs to do, which is why it is not particularly good at what it is doing, so people need to tack on important functionality by way of shell scripts. Note: If your engine uses a hundred shell scripts which are all substantially the same, this might tell you that perhaps some functionality could be usefully added to your engine such that your configuration does not need to be quite that complex. Also for the longest time even the complex configuration of sysvinit needed considerable ad-hoc human expertise to manage; in the history of sysvinit over the last 30 years or so, the automatic management of dependencies between services hasn't been around all that long, and that is one area where a little more complexity in the engine would really have been quite helpful.

Also, if one considers not just sysvinit but the whole “basic plumbing” that systemd replaces (including such beauties as the distribution-specific boot scripts or inetd/xinetd), then any claim of simplicity goes right out the window. The individual components on their own may be pretty simple but their totality isn't (and distribution-specific design choices figure into it, too, so if you have figured out how distribution X does its thing, that may or may not apply to distribution Y), and in spite of all the complexity they don't really form a coherent system that works well together. Systemd is a lot more advanced in that respect.

Which is not to say that systemd is the epitome of internal simplicity – but the systemd developers do care about things like code reuse, and facts like that all the configuration files use the same format (and presumably share the same parser) do suggest that systemd isn't the most complex piece of software in existence, either. It is probably a lot simpler internally than, say, the Linux kernel, or for that matter the sum total of sysvinit and friends.