System initialization and service management

System initialization and service management Mark Heily mark@heily.com Jonathan de Boyne Pollard J.deBoynePollard-newsgroups@NTLWorld.COM Jordan Hubbard jkh@freebsd.org A comparison of init(8) and rc(8) replacements

There are three active projects to provide an alternative to the traditional init(8) and rc(8) subsystems that manage the boot process and system services. There are a number of reasons driving the desire to change, including:

faster boot times, made possible by launching services in parallel;
greater reliability, by ensuring that services are automatically restarted if they die;
simplified dependency management, using socket activation and similar techniques
the ability to launch services "on demand", and have them self-terminate when idle;
improved security by removing the need to start common daemons as the root user

Two of the projects, launchd and relaunchd, are based on the launchd(8) API introduced by Apple in Mac OS X. The NextBSD project has ported the original Apple source code by writing a Mach compatibility layer that allows it to run on FreeBSD. The relaunchd project started from scratch with the goal of creating a more modular, lightweight, and portable implementation of the launchd API. The third project, nosh, is a unique creation that also borrows concepts from launchd, systemd, and several other Unix operating systems.

While the FreeBSD project has not officially made a decision to replace the current init(8) and rc(8) subsystems, the existence and active development of alternatives will continue to drive innovation in this space.