G. Pape
runit - a UNIX init scheme with service supervision
How to install runit
Upgrading from previous versions of runit
Benefits
How to replace init
How to use runit with current init
How to use dietlibc
Frequently asked questions
Runlevels
Service dependencies
A collection of run scripts
The runit program
The runit-init program
The sv program
The runsvdir program
The runsvchdir program
The runsv program
The svlogd program
The chpst program
The utmpset program
runit is a
cross-platform Unix init scheme with service supervision, a replacement for
sysvinit,
and other init schemes.
It runs on GNU/Linux, *BSD, MacOSX, Solaris,
and can easily be adapted to other Unix operating systems.
If runit runs for you on any other operating system, please
let me know.
runit is discussed on the
<supervision@list.skarnet.org>
mailing list.
Please contact this list and not me privately.
To subscribe send an empty email to
<supervision-subscribe@list.skarnet.org>.
Mailing list archives are available at
skarnet.org, and
gmane.org.
The program runit is intended to run as Unix
process no 1, it is automatically started by the
runit-init /sbin/init-replacement
if this is started by the kernel.
runit performs the system's booting,
running and shutting down in three stages:
- Stage 1:
runit starts /etc/runit/1 and waits for it to
terminate.
The system's one time initialization tasks are done here.
/etc/runit/1 has full control over /dev/console to be
able to start an emergency shell in case the one time initialization
tasks fail.
- Stage 2:
runit starts /etc/runit/2 which should not return
until the system is going to halt or reboot; if it crashes, it will be
restarted.
Normally, /etc/runit/2 runs
runsvdir.
In Stage 2 runit optionally handles the INT signal (ctrl-alt-del
keyboard request on Linux/i386).
- Stage 3:
If runit is told to halt or reboot the system, or Stage 2 returns
without errors, it terminates Stage 2 if it is running, and runs
/etc/runit/3.
The systems tasks to shutdown and halt or reboot are done here.
These are working examples for Debian sarge:
/etc/runit/1,
/etc/runit/2,
/etc/runit/3.
The program runit-init is intended to
replace /sbin/init.
The command init 0 tells runit to halt the system,
and init 6 to reboot.
Runlevels are handled through the
runsvdir and
runsvchdir programs.
Service dependencies are resolved
automatically.
runit is optimized for reliability and small size.
The amount of code in process no 1 should be minimal.
See How to install runit for installing
runit, and How to replace init for
configuring runit to run as process no 1.
See How to use with current init if you want to
use runit without replacing the current init scheme.
Please read the list of
Frequently asked questions with answers.
If runit on Linux is compiled and linked with the
dietlibc, it yields in a
statically linked runit binary of 8.5k size and this
ps axuw output on my system:
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 1 0.0 0.0 20 16 ? S 2002 0:02 runit
I recommend doing this; for instructions, see
How to use dietlibc.
The following distributions are known to include or package runit:
-
Debian GNU/Linux (as alternative init scheme)
-
FreeBSD
-
OpenBSD
-
NetBSD
-
Annvix (as default init scheme)
-
Ubuntu (as alternative init scheme)
-
Gentoo
-
SME server
-
OpenSDE
-
T2
-
Zinux Linux (as default init scheme)
-
GoboLinux
-
deepOfix Mail Server (as default init scheme)
-
Dragora GNU/Linux (as default init scheme)
-
ArchLinux
If you know of more distributions, please
let me know.
runit in use:
I replaced sysvinit successfully with runit on several server
systems and a laptop running Debian/GNU Linux sarge, woody, and potato.
Here is an example:
# strings /proc/1/exe |grep Id
$Id: runit.c,v 1.7 2002/02/13 09:59:52 pape Exp $
# uptime
11:59:13 up 365 days, 23:22, 3 users, load average: 0.01, 0.02, 0.00
# ps axuw |head -n20
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 1 0.0 0.0 20 16 ? S 2002 0:07 runit
root 2 0.0 0.0 0 0 ? SW 2002 0:00 [keventd]
root 3 0.0 0.0 0 0 ? SWN 2002 0:51 [ksoftirqd_CPU0]
root 4 0.0 0.0 0 0 ? SW 2002 144:38 [kswapd]
root 5 0.0 0.0 0 0 ? SW 2002 0:08 [bdflush]
root 6 0.0 0.0 0 0 ? SW 2002 7:24 [kupdated]
root 168 0.0 0.0 1652 168 ? S 2002 0:27 /usr/sbin/cron
root 174 0.0 0.0 36 24 ? S 2002 1:06 runsvdir /var/service log: ...............................................................................................
root 176 0.0 0.0 20 20 ? S 2002 0:00 runsv qmail-send
root 177 0.0 0.0 20 20 ? S 2002 0:00 runsv getty-5
root 178 0.0 0.0 20 20 ? S 2002 0:00 runsv getty-4
root 179 0.0 0.0 20 20 ? S 2002 0:00 runsv getty-3
root 180 0.0 0.0 20 20 ? S 2002 0:00 runsv getty-2
root 182 0.0 0.0 20 20 ? S 2002 0:00 runsv socklog-unix
root 183 0.0 0.0 1256 4 tty5 S 2002 0:00 /sbin/getty 38400 tty5 linux
root 184 0.0 0.0 1256 4 tty3 S 2002 0:00 getty 38400 tty3 linux
root 185 0.0 0.0 20 20 ? S 2002 0:00 runsv socklog-klog
root 186 0.0 0.0 20 20 ? S 2002 0:00 runsv ssh
root 187 0.0 0.0 1256 4 tty4 S 2002 0:00 getty 38400 tty4 linux
# pstree
runit-+-bdflush
|-cron
|-gcache
|-keventd
|-ksoftirqd_CPU0
|-kswapd
|-kupdated
`-runsvdir-+-runsv-+-multilog
| `-qmail-send-+-qmail-clean
| |-qmail-lspawn
| `-qmail-rspawn---qmail-remote
|-4*[runsv---getty]
|-2*[runsv-+-multilog]
| `-socklog]
|-runsv-+-multilog
| `-sshd-+-sshd---sshd---bash---bash---pstree
| `-sshd---sshd---rsync
|-runsv---clockspeed
|-runsv-+-dnscache
| `-multilog
|-runsv---apache-ssl-+-9*[apache-ssl]
| |-gcache
| `-4*[multilog]
|-7*[runsv-+-multilog]
| `-tcpserver]
|-4*[runsv-+-multilog]
| `-tinydns]
|-runsv---uncat
|-2*[runsv-+-multilog]
| `-tcpsvd]
|-runsv-+-svlogd
| `-tcpsvd-+-smtpfront-qmail
| `-smtpfront-qmail---qmail-queue
`-runsv-+-svlogd
`-tcpsvd---bincimap-up---bincimapd
See smarden.org/runit/
for recent informations.
Related links:
-
minit - a small yet feature-complete init
-
svscan as process 1 - by Paul Jarc
-
sysvinit - source code
-
FreeBSD's init - CVS repository
-
NetBSD's init - CVS repository
-
OpenBSD's init - CVS repository
-
Linux Boot Scripts - by Richard Gooch
Gerrit Pape <pape@smarden.org>
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is neither affiliated with the authors of this page nor responsible
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