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Comment by davexunit | Hacker News Reader

Shepherd is a wonderful little service manager. The project has been integrating the good features of systemd (socket activation, timers, etc.) while retaining the hackability of using a fully featured programming language for configuration. Been happily using it with Guix for over a decade!

NLnet has funded a really cool project to turn Shepherd into a distributed system that enables a fleet of Shepherds to cooperate. https://nlnet.nl/project/DistributedShepherd/

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Also a note since there are a number of comments on here about this being a rival for Systemd: Shepherd precedes Systemd by quite a bit! Shepherd was previously known as "dmd", the "daemon for managing daemons", which was made in 2003! So in that sense, if anything was imitating anything (and not claiming anything was), it would be the reverse :)

You've been using Guix for over a decade? Is there somewhere I can read more about your experience? I think Guix is a cooler version of nix but I've been put off by the lack of packages and smaller community.

Not OP, but I've been daily driving Guix for about 5 years now quite happily. The biggest paint point with vanilla Guix is probably a lack of non-libre packages, especially the linux-libre kernel which strips out blobs. However, the nonguix [1] channel handily fills that hole, and there is first-class support for running a Nix daemon service [0] to cover anything not in nonguix.

Guix documentation is top notch, and it's really nice having all that available locally as texinfo pages. For writing packages yourself, I've found the Guix source to be eminently more greppable than Nix, which eases the dev onramp.

Nix's daemon is definitely more performant than Guix's, so equivalent operations will usually be quite a bit slower in Guix, but on the whole I'd say that Guix's more cohesive design makes the system more pleasant to work with.

Happy to help if you have any specific questions!

[0] https://guix.gnu.org/manual/en/guix.html#Nix-service

[1] https://gitlab.com/nonguix/nonguix/

(I know I could just RTFM but since you offered!) Does it do something like NixOS for declaring modules as functions and resolving the configuration as a fixed point of all module function applications (roughly, I don't think I'm describing it well)? This is a beautifully elegant way of defining configuration-with-options using lazy evaluation but it often leads to headaches like infinite recursion. Since Guile is not a lazy language I wonder how it achieves this.

I don’t know how Guile does this, but note that finding a fixed point does not generally require a lazy language; you just can’t do it naively — you can still take a bunch of functions that act on a config and ‘while (changing) keep applying’ — equivalently, the Y combinator can’t be evaluated strictly to get your fixed points, but the Z combinator can.

In all honesty, I don't know what that means, but the way Guix does configuration is with the Lisp equivalent of a builder pattern, which ends up looking quite like a key-value store.

(foo-configuration (bar-property baz-value) ...)

> Shepherd is a wonderful little service manager

I believe you

But what practical use is it?

I cannot tell.

> practical use

service manager.

Where by you can create a service of your own application in userland without needing to be PID 1 to execute the service. With all the bells and whistles of monitoring and trigger.

Eh, I'd say systemd still has far better dmcrypt support. The bad (I used to think it was terrible, but I tried installing Debian today, which lowered the bar even further) support for full-disk encryption is what keeps me off Guix, as a matter of fact.

okay

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