Finit v1.8

It’s been a long time coming, but here it finally is, Finit v1.8! The goodies we’ve been waiting for are:

  • Runlevels
  • Multiple TTYs
  • One-shot tasks

Let’s start off with tasks. Tasks are one-shot commands, with a syntax like service directives, but are not monitored and respawned like services. Tasks are started in parallel, just like services. For some cases, like the system bootstrap phase, some tasks may need to be executed in sequence, and for that purpose there also exists a run command. Run commands are executed in the order listed in finit.conf and will run until completion before continuing with the next task or service.

Multiple TTYs is another neat feature. Similar to services many TTYs can be started and automatically be respawned when a user logs out. For embedded targets wanting to save CPU cycles usually one TTY is the system console. Use the console command to point to a defined TTY to activate “Press any key to activate this console.”

Finally, runlevels! This is the key feature in this release of Finit. Adding the flexibility from SysV init, without the complexity. This is one of the key points of Finit – it should be simple!

finit.conf:
    service [2345] /usr/sbin/sshd -D -- OpenSSH Daemon

This command tells Finit that the OpenSSH daemon should only run in runlevel 2-5. Finit will also respawn sshd if it should crash, just like before.

Runlevels are needed in use-cases in many embedded devices. E.g., bootstrap, upgrading, and regular operation. It is completely up to the system administrator to setup the runlevels of the product or installation. At boot runlevel ’S’ runs, well before any networking is up. This is used to to one-time probing and setup of the system. When done the runlevel defined in finit.conf, or the default 2, is started.

See the README for more information, or the code for the full details.