init/README.md

# About

This directory contains the source code for a tiny service supervision
framework devised for the Pygos system, consisting of an init daemon,
a small syslog daemon and various command line utilities.

The individual parts of the framework are designed to be independent of
each other (for instance, the tiny syslogd is intended to work with *any*
init system and other components of the framework don't depend on the presence
of this *specific* syslog implementation) and everything that is not strictly
part of the init system (such as the syslog daemon) can be disabled through
the configure script.


The programs of this package are developed first and foremost for GNU/Linux
systems, so there are some GNU and some Linux extensions used and some of the
code may unintentionally rely on Linux specific behavior.

Nevertheless, if sufficient interest exists, it should be possible to make it
run on BSDs or other Unix-like systems, but some effort may be required.


The init system tries to mimic the concept of unit files from systemd as those
were considered to be a good design choice.

In a typical setup, the parameterizeable service description files are stored
in `/usr/share/init` by default. Services are enabled by creating a symlink
in `/etc/init.d`. This can be done more conveniently using the `service`
command line tool.


A default setup is provided, as needed for the Pygos system, including helper
scripts for setting up mount points and for network configuration. If you want
to use the init daemon for another system, you may have to toss out or adapt
some of the default configuration and make your own.


Right now, the system is in a "basically works" proof of concept stage and
needs some more work to become usable.

There are plans for *maybe* *eventually* adding more fancy features like
support for Linux name spaces, seccomp filters and cgroups or network
back ends for the syslog daemon, but right now, features are added only
when the need arises.


See [docs/init.md](docs/init.md) for more information on the design,
implementation and caveats of the init daemon.

See [docs/cmdline.md](docs/cmdline.md) for an explanation on the available
command line tools.

See [docs/services.md](docs/services.md) for more information on service
description files.

See [docs/network.md](docs/network.md) for information on how the network
configuration works.

See [docs/defconfig.md](docs/defconfig.md) for an explanation on the default
services and configuration provided with this package.

See [docs/usyslogd.md](docs/usyslogd.md) for details on the tiny syslog
implementation.


## Why

There are already a bunch of similar projects out there that have been
considered for use in the Pygos system. The reason for starting a new
one was mainly dissatisfaction with the existing ones. Other Projects
that have been considered include:

- systemd

    Contains a lot of good ideas, but it is HUGE. It has tons of
    dependencies. It implements tons of things that it simply shouldn't.
    It has a horrid, "modern", python based, hipster build system.
    It's simply too damn large and complex.

- SystemV init

    A bad combination of unnecessary complexity where it isn't needed and a
    complete lack of abstraction where it would be needed. Shell script
    copy and paste madness. There are reasons people started developing
    alternatives (other than "hurr-durr-parallel-boots").

- upstart

    Seems nice overall, but needlessly big and complex for the intended
    use case in Pygos. Would have needlessly added D-Bus to the system.

- OpenRC

    Was already integrated into Pygos. Things turned out to be broken.
    Upstream developers did not accept fixes (after ignoring them for weeks
    and preferring typo fixes instead). Complaints from other people who
    tried to contribute fixes were observed on GitHub. Complaints from
    package maintainers about deteriorating code quality were observed
    on the official IRC channel. Documentation is non-existent.

- daemon tools and similar (runnit, s6, minit, ...)

    The sixties are over. And even code from that era is more readable. The
    source code for those projects should better be tossed out the window and
    rewritten from scratch. If you are a first semester CS student and you
    hand something like this in as a homework, the best you might get is a
    well deserved slap on the back of your head.

- busybox init

    Nice and simple. Probably the best fit if the rest of your user space is
    busybox as well.