> This argument, he said, seems to be predicated on the notion that systemd is a single, monolithic binary.
Can we please stop misrepresenting the complaints against systemd? The only time I ever hear this "monolithic binary" argument is from systemd advocates. The actual complaint is about tightly coupling important features together. Not only does this make it difficult (often impossible) to replace individual components, when tight coupling happens at the (internal) protocol level, any replacement component ne4cessarily hast to implement a bunch of (sometimes unwanted) systemd baggage.
Busybox implements all of its features in single monolithic binary, but it isn't a monolithic design that tightly couples those specific components together. Replacing one of busybox's components is often as simple as removing busybox's symlink and installing the replacement. This isn't even a "Unix philosophy" issue. Even inexperienced designers shouldn't have as hard time Understanding why systemd is a monolithic design but busybox isn't.
https://suckless.org/sucks/systemd/ has items like "pid 1 does DNS". It's an incorrect complaint that exists in the wild, though it certainly isn't the basis of all accusations that it violates the Unix philosophy.
It runs its own logging system with non-standard interfaces and formats. It runs its own DNS resolver with non-standard behaviour. It maintains compatibility only with a narrow range of udev versions, which in turn maintain compatibility only with a narrow range of kernel versions. And all the d-bus interfaces between these pieces may change at any point without notice. So you can't replace any piece of it, because even if you provide your own component that implements one of the systemd d-bus interfaces, you've got no forward compatibility.
Can we please stop misrepresenting the complaints against systemd? The only time I ever hear this "monolithic binary" argument is from systemd advocates. The actual complaint is about tightly coupling important features together. Not only does this make it difficult (often impossible) to replace individual components, when tight coupling happens at the (internal) protocol level, any replacement component ne4cessarily hast to implement a bunch of (sometimes unwanted) systemd baggage.
Busybox implements all of its features in single monolithic binary, but it isn't a monolithic design that tightly couples those specific components together. Replacing one of busybox's components is often as simple as removing busybox's symlink and installing the replacement. This isn't even a "Unix philosophy" issue. Even inexperienced designers shouldn't have as hard time Understanding why systemd is a monolithic design but busybox isn't.