.TH runit 8
.SH NAME
runit \- a UNIX process no 1
.SH SYNOPSIS
.B runit
.SH DESCRIPTION
.B runit
must be run as Unix process no 1.
It performs the system's booting, running, and shutdown in three stages:
.SH STAGE 1
.B runit
runs
.I /etc/runit/1
and waits for it to terminate.
The system's one time tasks are done here.
.I /etc/runit/1
has full control of
.I /dev/console
to be able to start an emergency shell if the one time initialization tasks
fail. If
.I /etc/runit/1
crashes, or exits 100,
.B runit
will skip stage 2 and enter stage 3.
.SH STAGE 2
.B runit
runs
.IR /etc/runit/2 ,
which should not return until system shutdown; if it crashes, or exits 111,
it will be restarted.
Normally
.I /etc/runit/2
starts
.BR runsvdir (8).
.B runit
is able to handle the ctrl-alt-del keyboard request in stage 2, see below.
.SH STAGE 3
If
.B runit
is told to shutdown the system, or stage 2 returns, it terminates stage 2 if
it is running, and runs
.IR /etc/runit/3 .
The systems tasks to shutdown and possibly halt or reboot the system are
done here.
If stage 3 returns,
.B runit
checks if the file
.I /run/runit.reboot
exists and has the execute by owner permission set.
If so, the system is rebooted, it's halted otherwise.
If
.I /etc/runit/nosync
exists,
.B runit
doesn't invoke sync(). This is useful in vservers.
.SH CTRL-ALT-DEL
If
.B runit
receives the ctrl-alt-del keyboard request and the file
.I /etc/runit/ctrlaltdel
exists and has the execute by owner permission set,
.B runit
runs
.IR /etc/runit/ctrlaltdel ,
waits for it to terminate, and then sends itself a CONT signal.
.SH SIGNALS
.B runit
only accepts signals in stage 2.
.P
If
.B runit
receives a CONT signal and the file
.I /run/runit.stopit
exists and has the execute by owner permission set,
.B runit
is told to shutdown the system.
.P
If
.B runit
receives a PWR signal,
.B runit
is told to shutdown the system.
.P
if
.B runit
receives an INT signal, a ctrl-alt-del keyboard request is triggered.
.SH ENVIRONMENT
When the
.I runitdir=name
variable is set and
.B runit
is init,
.B runit
will check if a directory named
.I name
exists in
.I /etc/runit/runsvdir/
and then will use
.B runsvchdir
to change the directory of
.B runsvdir
to
.I name
in place of the default.
.P
If
.I runitdir
is set to
.I runitdir=solo
.B runit
will use the
.I solo
directory for
.B runsvdir
and it will also refrain from start any sysv service that is enabled in
.I /etc/rc2.d/
This is intended for use with containers that need to start only some selected services.
.SH SEE ALSO
runit-init(8),
runsvdir(8),
runsvchdir(8),
sv(8),
runsv(8),
chpst(8),
utmpset(8),
svlogd(8)
.P
http://smarden.org/runit/
.SH AUTHOR
Gerrit Pape <pape@smarden.org>