Runlevel Support

Basic support for runlevels is included in Finit from v1.8. By default all services, tasks, run commands and TTYs listed without a set of runlevels get a default set [234] assigned. The default runlevel after boot is 2.

Finit supports runlevels 0-9, and S, with 0 reserved for halt, 6 reboot and S for services that only run at bootstrap. Runlevel 1 is the single user level, where usually no networking is enabled. In Finit this is more of a policy for the user to define. Normally only runlevels 1-6 are used, and even more commonly, only the default runlevel is used.

To specify an allowed set of runlevels for a service, run command, task, or tty, add [NNN] to your /etc/finit.conf, like this:

service [S12345] syslogd -n -x             -- System log daemon
run     [S]      /etc/init.d/acpid start   -- Starting ACPI Daemon
task    [S]      /etc/init.d/kbd start     -- Preparing console
service [S12345] <pid/syslogd> klogd -n -x -- Kernel log daemon

tty     [12345]  /dev/tty1
tty     [2]      /dev/tty2
tty     [2]      /dev/tty3
tty     [2]      /dev/tty4
tty     [2]      /dev/tty5
tty     [2]      /dev/tty6

In this example syslogd is first started, in parallel, and then acpid is called using a conventional SysV init script. It is called with the run command, meaning the following task command to start the kbd script is not called until the acpid init script has fully completed. Then the keyboard setup script is called in parallel with klogd as a monitored service.

Again, tasks and services are started in parallel, while run commands are called in the order listed and subsequent commands are not started until a run command has completed. Also, task and run commands are run in a shell, so pipes and redirects can be used.

The following examples illustrate this. Bootstrap task and run commands are also removed when they have completed, initctl show will not list them.

task [S] echo "foo" | cat >/tmp/bar
run  [S] echo "$HOME" >/tmp/secret

Switching between runlevels can be done by calling init with a single argument, e.g. init 5, or using initctl runlevel 5, both switch to runlevel 5. When changing runlevels Finit also automatically reloads all .conf files in the /etc/finit.d/ directory. So if you want to set a new system config, switch to runlevel 1, change all config files in the system, and touch all .conf files in /etc/finit.d before switching back to the previous runlevel again — that way Finit can both stop old services and start any new ones for you, without rebooting the system.