an init system that isn't smarter than you
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README.md

This project is abandoned. I've been thoroughly convinced that this is a problem being solved well by existing systems, notably the s6 process supervision suite of programs.

This repository will continue to stay up for archival purposes.

Beginning, an init system that isn't smarter than you

"Omnium rerum principia parva sunt." --Marcus Tullius Cicero

An ISC-licensed init system and service manager, designed to be deterministic and minimal, but not difficult to use.

Beginning is still a work-in-progress. Design choices may still change, and configurations may need to be updated often. You should keep an eye on the commit log and actually read the changes if you plan on installing this, until it is stable.

Requirements

  • bash
  • C compiler (for the executables in libexec/)
  • coreutils (busybox is known to be enough)
  • bash-completion (if usage of rc's completion script is desired)
    • pkg-config is needed to detect directory to install completion files to
  • (optional but highly recommended) beginning-scripts

Installation

  1. git clone https://github.com/somasis/beginning, or download a release

  2. make

    The makefile follows GNU Makefile standards, and can be influenced by variables such as DESTDIR, bindir, libdir, libexecdir,docdir, sysconfdir, and prefix. Variables for directories are changed in the source files.

    The top of the Makefile contains a full list of variables.

    If bash_completion should not be installed, set bash_completion to anything but 'true'.

  3. make install

Beginning only comes with two core daemons, hostname and randomseed which are considered to be important enough to be part of the default installation. All other daemon scripts written so far are located in beginning-scripts and are almost certainly needed if you wish to have a nice default system.

See beginning-scripts's README for usage.

Defaults

  • The PID 1 will be installed to $(PREFIX)$(bindir)/begin. To use it as the default init system, either add init=/bin/begin to your kernel's boot parameters, or make a symlink at /bin/init that points to begin.
  • A reboot/shutdown/poweroff/halt program is installed to $(PREFIX)$(bindir)/reboot. Run it as root to reboot, make a symlink to it named poweroff, halt, and shutdown in order to turn off the system.

Usage

After installation, /bin/begin will need to be linked to /bin/init. Or, you can just add init=/bin/begin to the kernel command line if you wish.

Rationale and Design choices

Prior art: OpenBSD init, systemd, Arch Linux initscripts, sinit

Beginning is my response to systemd and friends. I've used systemd, Upstart, OpenRC, Arch Linux's initscripts, and basically all of them leave a bit to be desired, are annoying to use, feel inconsistent, or do too much.

The philosophy behind it is very much akin to how BSD-style inits work.

Configuration is intended to be flexible, but not overbearing; in addition, I want it to be as deterministic as it can. The program should not have any functionality which decides for the user; things like providers for virtuals, order to run daemons in, and so on, should all be determined and executed the same way each time. While this does mean it requires some initial set up before you can safely reboot with Beginning as your init, it means that you can expect it to always run the same way, regardless of what changes on your system. (aside from obvious things such as removing daemons and stuff)

You could also consider this to be a demonstration of just how simple init systems really need to be; the most complex part of this is probably the daemon dependency resolution.

The actual init program is just 34 SLOC, because all init has to do is sleep forever, and handle shutdown and reboot signals. bash takes care of reparenting children processes for us.

Beginning can be ran with theoretically any sensible filesystem layout, but for intents of compatibility and forward-looking practices, it expects the filesystem to loosely adhere to systemd's own file-hierarchy(7) guidelines.

file-hierarchy(7) is used because it provides some compatibility with programs that expect the layout, distributions which have adopted it, as well as the author liking it.

What it does have

  • PID 1
    • Only handles shutdown, reboot, and starting the service manager
  • Service management
    • Daemon starting, with dependency resolution
    • Virtuals, with customizable providers for them (network/syslog/udev, etc.)
    • rc, the main way for interacting with Beginning
    • rc.conf, which allows for lots of configuration

What it does not have

  • No runlevels (telinit 1, systemctl start multi-user.target, etc.)
  • No network management (use a separate daemon for that)
  • No socket managing
    • Not enough possible benefits of using sockets for daemons. If you have to keep starting and stopping sshd instances when users come and go to conserve resources, you might have bigger problems on your hands.
  • No enable/disable functionality in rc
    • Keeping in line with having deterministic functionality, it seems to me that having the boot sequence be affected by a command line program, rather than explicit configuration editing would go against Beginning's philosophy.
    • OpenBSD apparently switched to using key=value format for their rc.conf; but we don't want to do that because having functions in rc.conf is nice.