s6-linux-init
What is it?
s6-linux-init is a set of minimalistic tools used to create a s6-based init system, including a /sbin/init binary, on a Linux kernel. It is a part of the s6 ecosystem.
The resulting architecture follows the Unix philosophy (one job → one tool) as closely as possible, and is fully dedicated to the s6 way of managing a system:
- s6-svscan runs as process 1 for the whole machine lifetime.
- Every daemon is supervised.
- No logs are ever lost.
- Policy is entirely left to the user. Typically, any service manager can be run on top of s6-linux-init.
Nevertheless, the architecture is fully compliant with various empirical and historical specifications. For instance, it provides:
- utmp management compatible with sysvinit
- runlevel management, with a configurable default, overridable from the kernel command line
- sysvinit-like commands to shut the system down, including a shutdown command that follows the LSB specification
- Why s6-linux-init?
- An overview of s6-linux-init
- A quickstart guide for the impatient, along with a FAQ
Installation
Requirements
- A Linux-based system with a standard C development environment
- GNU make, version 3.81 or later
- skalibs version 2.15.0.0 or later. It's a build-time requirement. It's also a run-time requirement (for s6-linux-init-maker) as well as a boot-time requirement (i.e. a run-time requirement for the programs used when you boot a system created with s6-linux-init-maker) if you link against the shared version of the skalibs library.
- execline version 2.9.9.0 or later. It is a build-time and boot-time requirement.
- s6 version 2.15.0.0 or later. It is a build-time and boot-time requirement.
The following optional dependencies are also supported:
- If you're using musl and want nsswitch-like functionality: nsss version 0.2.1.2 or later (build-time and boot-time)
- If you want secure utmp functionality: utmps version 0.1.3.3 or later (build-time and boot-time)
Licensing
s6-linux-init is free software. It is available under the ISC license.
Download
- The current released version of s6-linux-init is 1.2.0.1. You can access its checksum here.
- Alternatively, you can checkout a copy of the
s6-linux-init
git repository:
git clone git://git.skarnet.org/s6-linux-init
- There's also a Codeberg mirror, or a GitHub mirror, or a SourceHut mirror of the s6-linux-init git repository.
Compilation
- See the enclosed INSTALL file for installation details.
Upgrade notes
- This page lists the differences to be aware of between the previous versions of s6-linux-init and the current one.
Reference
General
- A rationale for this package
- An overview of s6-linux-init
- A quickstart page
Commands
Unless more details are provided in an Exit codes section of a specific page, all these commands exit 0 on success, 111 if they encounter a temporary error (such as a system call failure) and 100 if they encounter a permanent error (such as a misuse).
- The s6-linux-init-maker program
- The s6-linux-init program
- The s6-linux-init-hpr program
- The s6-linux-init-shutdown program
- The s6-linux-init-shutdownd program
- The s6-linux-init-telinit program
- The s6-linux-init-logouthookd program
- The s6-linux-init-echo program
- The s6-linux-init-nuke program
- The s6-linux-init-umountall program
Related resources
- s6-linux-init is discussed on the skaware and supervision mailing-lists.
- There is a #s6 IRC channel on OFTC. Sometimes people are there and even answer questions.
s6-linux-init manual pages
- Lennart Jablonka is providing the s6-linux-init documentation as a set of man pages.