What are the best Linux init systems?

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score 20 · Answer 1

OpenRC

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Top Pro

No feature creep

OpenRC follows the UNIX philosophy of 'do one thing and do it well', while it's true that it has more features than sysvinit, it does not stay away from its primary function with unnecessary added features. See More

Top Con

No socket activation

OpenRC does not have socket activation yet. It will be added in the future though. See More

Top Pro

Fast

OpenRC builds on top of sysvinit and adds some more useful features (like parallel booting) while still the simplicity that sysvinit is know for. Because of this it generally boots faster than other init systems, especially when parallel booting is enabled. See More

Top Pro

Extremely simple

All configuration is done via shell scripts and symlinks. Shell scripts can then use various specialized utilities to ease the development of init scripts. See More

Top Pro

A very balanced compromise

Basically OpenRC doesn't replace SysV init, but rather works with it, providing features that SysV is lacking while taking advantage of its benefits. It's also used by a fair amount of reasonably popular distros and is well supported and developed. See More

Top Pro

Less dependency creep

Using OpenRC does not lock in a distribution by providing specific NON-POSIX extra services which programs then would rely on. See More

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score 8 · Answer 2

runit

Top Pro

Small and Unix-like

One of the runit project's principles is to keep the code size small. As of version 1.0.0 of runit, the runit.c source contains 330 lines of code; the runsvdir.c source is 274 lines of code, the runsv.c source 509. This minimizes the possibility of bugs introduced by programmer's fault, and makes it more easy for security related people to proofread the source code. The runit core programs have a very small memory footprint and do not allocate memory dynamically. See More

Top Pro

Fast, parallel startup

After the system's one time tasks (stage 1) are done, the system services are started up in parallel. The operating system's process scheduler takes care of having the services available as soon as possible. See More

Top Pro

Easy to use

Simple scripts linked to the proper directory is all that's needed to bring a service up at boot, and everything is up and running quickly. See More

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score 10 · Answer 3

sysvinit

Top Pro

Simple to understand

Top Con

Can lead to slow boot

Since init starts tasks serially, it has to wait for a certain task to finish in order to start the next one. But when startup processes end up I/O blocked, this leads to considerable delays during boot. See More

Top Pro

Very stable

Since sysvinit does only one thing (initialize the system) and one thing only, it's very stable and it's impossible for it to fail for any problems unrelated to booting the system. See More

Top Con

Duplicated implementation for every service

Every init script needs to reinvent the wheel for every script: argument processing, start/stop/restart/reload/status/whatever processing, finding/clearing/creating PID files, sourcing defaults, building and setting configuration options, so on and so forth. See More

Top Pro

Better boot time and overall performance

Top Con

Launches a bunch of processes to launch a process

Every init script spawns at least sh/dash/bash, and probably also additional processes such as cat, echo, start-stop-daemon, etc, just to start a single daemon that may not even be needed at the time of boot. This massive overhead results in poor performance, and is a killer for embedded systems. See More

Top Con

Initscripts is not portable

It is virtually impossible to write portable sysvinit-scripts See More

Top Con

Hard to write sysv-initscripts

As one needs programming skills (opposed to a declarative style). See More

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score 22 · Answer 4

systemd

Top Con

Not UNIX-like

One of the main argument that people who are against using systemd is that it does not follow on of UNIX'S core philosophies. 'Do one thing and do it well', instead systemd represents a collection of dozens of tightly coupled libraries. With responsibilities that exceed those of a simple init system because it also tries to handle things like device management, power management, mount points, cron, encryption, syslog, network configuration etc... See More

Top Pro

Default for many popular distributions

Systemd is the default init system for many popular Linux distributions (Arch, Debian, Ubuntu, openSUSE, Fedora, etc..). It should also be noted that some of those distributions allow users to use a different init system if they want. See More

Top Con

Makes dependent products difficult to port

Software dependent on systemd. Becomes difficult to port to systems that lack systemd. See More

Top Pro

Login management out of the box

Systemd contains a daemon called logind which is used for managing user logins. See More

Top Con

Too monolithic

It tries to do too much. I don't think most people who use systemd are even aware of most of the features as they don't really use them. It makes it really complicated to deal with sometimes, and it's possible that in a few years this project will be a nightmare to maintain, and with that the users of it will start to feel the fallout. See More

Top Pro

Cgroups processes control

Systemd groups all processes by services using Linux's cgroups. Think about memory/cpu/tasks/IO/Net limits and accounting for any service. See More

Top Con

Un-trustworthy

Very Mac like developer that 'knows whats best for the user' See More

Top Pro

UNIX-Like

WTF? SYSTEMD UNIX-LIKE?????????? See More

Top Con

Lead developer shows near complete lack of care for standards of quality needed for developing a part of an OS as integral as the init system is

See All

score 4 · Answer 5

Upstart

Top Con

Ubuntu abandoned it

The original developers (Canonical) seem to have abandoned this project. At least they're no longer using it in Ubuntu. See More

Top Pro

Simple .conf file in /etc/init

Top Con

It was just sysvinit or systemd in disguise

It really just offered a barely more intuitive way to create init scripts for the actual init system running behind upstart. See More

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What are the best Linux init systems?

5 Options Considered

OpenRC

My Recommendation for OpenRC

My Recommendation for OpenRC

No feature creep

No socket activation

Fast

Extremely simple

A very balanced compromise

Less dependency creep

runit

My Recommendation for runit

My Recommendation for runit

Small and Unix-like

Fast, parallel startup

Easy to use

sysvinit

My Recommendation for sysvinit

My Recommendation for sysvinit

Simple to understand

Can lead to slow boot

Very stable

Duplicated implementation for every service

Better boot time and overall performance

Launches a bunch of processes to launch a process

Initscripts is not portable

Hard to write sysv-initscripts

systemd

My Recommendation for systemd

My Recommendation for systemd

Not UNIX-like

Default for many popular distributions

Makes dependent products difficult to port

Login management out of the box

Too monolithic

Cgroups processes control

Un-trustworthy

UNIX-Like

Lead developer shows near complete lack of care for standards of quality needed for developing a part of an OS as integral as the init system is

Upstart

My Recommendation for Upstart

My Recommendation for Upstart

Ubuntu abandoned it

Simple .conf file in /etc/init

It was just sysvinit or systemd in disguise

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