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howtos:slackware_admin:runit [2018/12/20 09:16 (UTC)]
chrisabela [6. runsv]
howtos:slackware_admin:runit [2020/05/06 08:08 (UTC)] (current)
chrisabela [Startup and Shutdown]
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 ====== Runit ====== ====== Runit ======
  
-===== 1. Introduction =====+===== Introduction =====
  
 runit is a UNIX init scheme with service supervision. It is a cross-platform Unix init scheme with service supervision, a replacement for sysvinit, and other init schemes and supervision that are used with the traditional init. runit is compatible with djb's daemontools. runit is a UNIX init scheme with service supervision. It is a cross-platform Unix init scheme with service supervision, a replacement for sysvinit, and other init schemes and supervision that are used with the traditional init. runit is compatible with djb's daemontools.
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 To read on the benefits of runit, see here: http://smarden.org/runit/benefits.html To read on the benefits of runit, see here: http://smarden.org/runit/benefits.html
  
-===== 2. Use runit with traditional init =====+//* Unless otherwise stated, all commands in this article are to be run by root.// 
 + 
 +===== Use runit with traditional init (sysvinit) =====
  
 runit is not provided by Slackware, but a SlackBuild is maintained on https://slackbuilds.org/. It does not have any dependencies. runit is not provided by Slackware, but a SlackBuild is maintained on https://slackbuilds.org/. It does not have any dependencies.
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 </code> </code>
  
-For a typical Slackware-stlyle service, you can also edit ''/etc/rc.d/rc.local'' file+==== Starting via rc.local ==== 
 + 
 +For a typical Slackware-stlyle service, you can edit ''/etc/rc.d/rc.local'' file
  
 <code> <code>
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 fi fi
 </code> </code>
- 
-if you require it. 
  
 and then edit write ''/etc/rc.d/rc.local_shutdown'' and then edit write ''/etc/rc.d/rc.local_shutdown''
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 #!/bin/sh #!/bin/sh
 RUNIT=x$( /sbin/pidof runsvdir ) RUNIT=x$( /sbin/pidof runsvdir )
-if [ $RUNIT” !=  x ]; then+if [ "$RUNIT!=  x ]; then
   kill $RUNIT   kill $RUNIT
 fi fi
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 and reboot and reboot
  
-===== 3. Using runit with sysvinit and inittab =====+==== Starting via inittab (supervised) ====
  
 Remove the entries in ''/etc/rc.d/rc.local'' and ''/etc/rc.d/rc.local_shutdown'' described above.  Remove the entries in ''/etc/rc.d/rc.local'' and ''/etc/rc.d/rc.local_shutdown'' described above. 
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 or reboot  or reboot 
  
-===== 4. How to replace init with runit =====+===== How to replace init with runit ===== 
 + 
 +runit provides ''runit-init'' which can be used to boot up the system.
  
 If you followed the previous chapter, then stop runsvdir and reverse all the changes that you made on your system. If you followed the previous chapter, then stop runsvdir and reverse all the changes that you made on your system.
  
-Remove the last line from ''/etc/inittab''+So, remove the last line from ''/etc/inittab''
  
 <code> <code>
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 </code> </code>
  
-Reboot:+And reboot:
  
 <code> <code>
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 Also, it is best to re-build and re-install runit Also, it is best to re-build and re-install runit
  
-This time, when running slackbuild, do pass any value for CONFIG, or set it to yes:+This time, when running slackbuild, do pass not any value for CONFIG, or set it to yes:
  
 <code> <code>
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 <code> <code>
 append="vt.default_utf8=0 init=/sbin/runit-init" append="vt.default_utf8=0 init=/sbin/runit-init"
-<code>+</code>
  
 Then run lilo: Then run lilo:
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 However, with the last alternative, be warned that if you had booted with the original init, the system may refuse to reboot, therefore boot from runit-init first.  However, with the last alternative, be warned that if you had booted with the original init, the system may refuse to reboot, therefore boot from runit-init first. 
  
-===== 5. Startup and Shutdown =====+==== Startup and Shutdown ====
  
-The traditional init reads ''/etc/inittab'' file to see how to run the system. It runs the ''/etc/rc.d/rc.S'' script and runs it. If set in the default runlevel 3, it follows it with ''/etc/rc.d/rc.M''. In runit the initialisation script is located in ''/etc/runit/1'' for all runlevels. By default ''/etc/runit/2'' is restricted to the TTY services+The BSD style init scripts provided by Slackware are used to bring up the system.
  
-The script ''/etc/rc.d/rc.6'' is the rebooting script for the traditional init, while ''/etc/rc.d/rc.0'' (symlinked to former) is the halting script. In runit, these scripts are called by ''/etc/runit/3''+Initially the single user script ''/etc/rc.d/rc.S'' runs. If set in the default runlevel 3, it follows it with ''/etc/rc.d/rc.M''. In runit the initialisation script is located in ''/etc/runit/1'' for all runlevels. By default ''/etc/runit/2'' is restricted to the TTY services.  
 + 
 +The script ''/etc/rc.d/rc.6'' is the rebooting script for the traditional init, while ''/etc/rc.d/rc.0'' (symlinked to the former) is the halting script. In runit, these scripts are called by ''/etc/runit/3''
  
 Note that the shutdown command provided by sysvinit package will not work in runit. To reboot you enter Note that the shutdown command provided by sysvinit package will not work in runit. To reboot you enter
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 The ''halt'', ''reboot'' and ''poweroff'' commands provided by the sysvinit package would still work with runit. The ''halt'', ''reboot'' and ''poweroff'' commands provided by the sysvinit package would still work with runit.
  
-===== 6. runsv ===== +Desktop Environments call ''/sbin/shutdown'' so they will not work until you move this file and symlink it to ''/usr/sbin/shutdown''
- +
-Although runit may replace init as the PID 1 daemon, there is not much benefit unless other services are migrated from Slackware’s BSD style to runsv(8). While this is not a complicated task, some familiarisation with runit’s characteristics is recommended and makes the task easier. This short example should help illustrate runsv to new users. +
- +
-Make an arbitrary directory under ''/etc/sv/''+
  
 <code> <code>
-mkdir /etc/sv/example/+mv /sbin/shutdown /sbin/shutdown.sysv 
 +ln -s /usr/sbin/shutdown /sbin/shutdown
 </code> </code>
  
-In order to let the non-privileged user (say user chrisrun itchange the ownership of the service directory+However consider that shutdown would not work for the original init. 
 + 
 +===== runsv ===== 
 + 
 +Although runit may replace init as the PID 1 daemon, there is not much benefit unless other services are migrated from Slackware's BSD style to runsv(8). While this is not a complicated tasksome familiarisation with runit's characteristics is recommended and makes the task easier. This short example should help illustrate runsv to new users. 
 + 
 +Make an arbitrary directory under ''/etc/sv/''
  
 <code> <code>
-chmod -R chris.users /etc/sv/example+mkdir /etc/sv/example/
 </code> </code>
  
-As a non-priviliged user, create some directories+As a non-priviliged user (say user bob), create some directories:
  
 <code> <code>
-mkdir -p /home/chris/runit/logs+mkdir -p /home/bob/runit/logs
 </code> </code>
  
-Then edit a script that simulates a (finicky) service in a convenient directory; say +Then edit a ''/home/bob/runit/service.sh'' script that simulates a (finicky) service in a convenient directory; say 
  
 <code> <code>
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 <code> <code>
-chmod +x /home/chris/runit/service.sh+chmod +x /home/bob/runit/service.sh
 </code> </code>
  
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 <code> <code>
-/home/chris/runit/service.sh+/home/bob/runit/service.sh
 </code> </code>
  
-Log back to rootand edit a file called ''/etc/sv/example/run'' and give it executable permissions+Log in back as root and edit a file called ''/etc/sv/example/run'' and give it executable permissions:
  
 <code> <code>
 #!/bin/sh -e #!/bin/sh -e
 exec 2>&1 exec 2>&1
-exec chpst -u chris /home/chris/runit/service.sh+exec chpst -u bob /home/bob/runit/service.sh
 </code> </code>
  
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 </code> </code>
  
-and edit another file under it also called ''/etc/sv/example/log/run''+and edit another file under italso called ''/etc/sv/example/log/run''
    
 <code> <code>
 #!/bin/sh #!/bin/sh
-exec chpst -u chris svlogd -tt /home/chris/runit/logs+exec chpst -u bob svlogd -tt /home/bob/runit/logs
 </code> </code>
  
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 </code> </code>
  
-Run the sv service to ensure that it works:+Run the service to ensure that it works:
  
 <code> <code>
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 </code> </code>
  
-Watch how your service” works, crashes, but it is recovered by runit:+Watch how your "serviceworks, crashes, but it is recovered by runit
 + 
 +As your non-privilged user:
  
 <code> <code>
-tail -f /home/chris/logs/current +tail -f /home/bob/runit/logs/current 
 </code> </code>
  
-===== 7.  Managing Services with sv =====+Hit CTRL+C to exit. 
 + 
 +Finally, login back as root and let bob take the ownership of the whole ''/etc/sv/example/'' directory: 
 + 
 +<code> 
 +chown -R bob.users /etc/sv/example/ 
 +</code> 
 + 
 +Now bob can manage this service with the ''sv'' command. Note that in most cases, services should belong to root, and only to root. 
 + 
 +=====  Managing Services with sv =====
  
 To see the status of a supervised service use ''sv s <service_name>'', for example, To see the status of a supervised service use ''sv s <service_name>'', for example,
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 sv s /service/* sv s /service/*
 </code> </code>
-==== 7.1. Stop/Start/Restart ====+ 
 +==== Stop/Start/Restart ====
  
 Start a service Start a service
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 </code> </code>
  
-Each of these is a shortcut, for updown, and terminate, respectively. Only the first letter of each word is recognised. +Each of these is a shortcut, for 'up''down', and 'terminate', respectively. Only the first letter of each word is recognised. 
-More verbose forms of the above+ 
 +More verbose forms of the above:
  
 <code> <code>
-sv start sshd+sv start example
  
-sv stop sshd+sv stop example
  
-sv restart sshd+sv restart example
 </code> </code>
  
 Each of these will also return the status of the service upon exit. Each of these will also return the status of the service upon exit.
  
-==== 7.2. Enabling a service ====+==== Enabling a service ====
  
 Service directories are placed under ''/etc/sv/''. To enable a service in the current runlevel, create a symlink from it to ''/service''. Service directories are placed under ''/etc/sv/''. To enable a service in the current runlevel, create a symlink from it to ''/service''.
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 Once a service is linked it will always start on boot and restart if it stops (unless this is disabled). Once a service is linked it will always start on boot and restart if it stops (unless this is disabled).
  
-==== 7.3. Disabling a service ====+==== Disabling a service ====
  
 To disable a service in the current runlevel remove the symlink to its service directory from ''/service''. To disable a service in the current runlevel remove the symlink to its service directory from ''/service''.
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 touch /etc/sv/service/down touch /etc/sv/service/down
 </code> </code>
-==== 7.4. Dependencies ====+ 
 +==== Dependencies ====
  
 Dependencies of service are supported by starting the dependent run script as follows: Dependencies of service are supported by starting the dependent run script as follows:
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 . .
 . .
-exec +exec ...
 </code> </code>
-===== 8. Runlevels ===== 
  
-If you installed the slackbuild configuration files, you have two runlevels: default and single. The current runlevel is default. You can verify by looking under ''/etc/runit/runsvdir/,'' you will see that ''/etc/runit/current'' is a symbolic link ''/etc/runit/default''.+==== Runlevels ==== 
 + 
 +If you installed the slackbuild configuration files, you have two runlevels: default and single. The current runlevel is default. You can verify by looking under ''/etc/runit/runsvdir/,'' you will see that ''/etc/runit/runsvdir/current'' is a symbolic link ''/etc/runit/runsvdir/default/''.
  
 Change runlevel to another runlevel; single: Change runlevel to another runlevel; single:
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 </code> </code>
  
-You will see that ''/etc/runit/runsvdir/current'' is now symlinked to ''/etc/runit/runsvdir/single'' and ''/etc/runit/runsvdir/previous'' is symlinked to ''/etc/runsvdir/default''. If you reboot, you will boot again default runlevel as you have this entry in ''/etc/runit/2''+You will see that ''/etc/runit/runsvdir/current'' is now symlinked to ''/etc/runit/runsvdir/single'' and ''/etc/runit/runsvdir/previous'' is symlinked to ''/etc/runsvdir/default''. If you reboot, you will boot again on the default runlevel as you have this entry in ''/etc/runit/2''
  
 <code> <code>
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 </code> </code>
  
-You can create any other runlevel and name them as you like. To start you can copy an existing runlevel directory and modify as you wish. +You can create any other runlevel and name them as you like. To startyou can copy an existing runlevel directory and modify as you wish. 
  
 <code> <code>
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 You can edit the runsvdir line of ''/etc/runit/2'' to your requirements. You can edit the runsvdir line of ''/etc/runit/2'' to your requirements.
-===== 9. run scripts ===== 
  
-Only one executable can be called for a service and the last line must be called by the ''exec'' command. There are some generic runit run scripts on the Internet, in other Linux distributions. Also, other Slackers may post them on publicly available repositories. The author of this article has placed his here: https://gitlab.com/chrisabela/runit_scripts_for_slackware+===== Run scripts ===== 
 + 
 +Only one executable can be called for a service (the last line) and it must be called by the ''exec'' command. There are some generic runit run scripts on the Internet and on other Linux distributions. Also, other Slackers may post them on publicly available repositories. The author of this article has placed his here: https://gitlab.com/chrisabela/runit_scripts_for_slackware 
 + 
 +Another set of installable run scripts are available at [[https://slackbuilds.org/repository/14.2/system/runit-services/|SBo]].
  
-In direct contrast to Slackwares BSD style service scripts, runit run scripts must not must run in the foreground, otherwise runit would think that they have crashed and restart them.+In direct contrast to Slackware's BSD style service scripts, runit run scripts must not must run in the foreground, otherwise runit would think that they have crashed and restart them.
  
 For some services, this may not be possible, but there are workarounds. You can forcefully terminate them by ending the run script like this: For some services, this may not be possible, but there are workarounds. You can forcefully terminate them by ending the run script like this:
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 </code> </code>
  
-Or you can use the ''pause'' command to keep the service alive. ''pause'' is a trivial command that will simply not exit, until it is killed (akin to tail -f /dev/null). A SlackBuild for ''pause'' is available at https://slackbuilds.org Then end the run script with:+Or you can use the ''pause'' command to keep the service alive. ''pause'' is a trivial command that will simply not exit, until it is killed (akin to tail -f /dev/null). A SlackBuild for ''pause'' is available at [[https://slackbuilds.org/repository/14.2/system/pause/|SBo]]. Then end the run script with:
  
 <code> <code>
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 </code> </code>
  
-===== 10. Migrating Services =====+===== Migrating Services =====
  
-It is suggested that services are migrated from stage 2 (which are still under the Slackwares BSD init scheme) to stage 3 carefully. Start from the bottom of ''/etc/rc.d/rc.M'' and work up. This means that you should start with any entries under ''/etc/rc.d/rc.local'' +It is suggested that services are migrated from stage 2 (which are still under the Slackware's BSD init scheme) to stage 3 carefully. Start from the bottom of ''/etc/rc.d/rc.M'' and work up. This means that you should start with any entries under ''/etc/rc.d/rc.local'' 
  
 Then continue for ''/etc/rc.d/rc.S'' Then continue for ''/etc/rc.d/rc.S''
  
-Proceed with other services to benefits from runit features. Note that for some services, such as ''atd'' and ''crond'', you would need to edit ''/etc/rc.d/rc.M'' as they are hard-coded.+Proceed with other services to benefit's from runit features. Note that for some services, such as ''atd'' and ''crond'', you would need to edit ''/etc/rc.d/rc.M'' as they are hard-coded.
  
-Lets take the popular ''NetworkManager'' service as an example. According to the permission of ''/etc/rc.d/rc.networkmanager'' this script is called by ''/etc/rc.d/rc.M'' The latter is called by ''/etc/runit/2'' (stage 2).+Let's take the popular ''NetworkManager'' service as an example. According to the permission of ''/etc/rc.d/rc.networkmanager'' this script is called by ''/etc/rc.d/rc.M'' The latter is called by ''/etc/runit/2'' (stage 2).
  
 Stop the service: Stop the service:
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 </code> </code>
  
-For ''udev'', it is stuggested to let it under runit’s stage 2but you can setup its monitoring for stage 3+If run exits and ''/etc/sv/<service name>/finish'' exists (typically when the service is switched off)''runsv'' runs ''finish'' if it has executable permission.
  
-===== 11. Sources ===== +It is stuggested to let ''udev'' under runit's stage 2, but you can setup its monitoring for stage 3.  
-  + 
-(1) http://smarden.org/runit/+===== Using runit-init with other init scripts ===== 
 + 
 +==== OpenRC ==== 
 + 
 +Here ''runit-init'' is used for booting, which then transfers control to the OpenRC for things like mounting the filesystem, loading modules, running udev, etc. 
 + 
 +It requires a working OpenRC system. Check the [[howtos:general_admin:openrc]] page for instructions. 
 +The level 1 runit service uses the OpenRC ''boot'' and ''sysinit'' runlevels.
  
-(2) https://slackbuilds.org+The [[https://wiki.gentoo.org/wiki/Runit#Runit_as_the_init_system|gentoo wiki]] has more information, and [[https://gitlab.com/aadityabagga/runit-init-openrc|runit-init-openrc]] details how to install and set it up.
  
-(3) https://en.wikipedia.org/wiki/Init+==== void-runit ====
  
-(4) https://voidlinux.org/usage/runit/+Here the scripts provided by the [[https://github.com/void-linux/void-runit|void-runit]] project are used to mount the filesystem, load modules, etc.
  
-(5) https://www.youtube.com/watch?v=jiBlIhFxNJo+Currently this is the most independent way to setup runit.
  
-(6) http://kchard.github.io/runit-quickstart/+===== Sources =====
  
-(7) https://www.slackbook.org/beta/+  - http://smarden.org/runit/ 
 +  - https://en.wikipedia.org/wiki/Init 
 +  - https://voidlinux.org/usage/runit/ 
 +  - https://www.youtube.com/watch?v=jiBlIhFxNJo 
 +  - http://kchard.github.io/runit-quickstart/ 
 +  - https://www.slackbook.org/beta/ 
 +  - https://gitlab.com/chrisabela/runit_scripts_for_slackware 
 +  - https://github.com/aadityabagga/runit-services 
 +  - https://wiki.gentoo.org/wiki/Runit 
 +  - https://github.com/void-linux/void-runit
  
-(8) https://gitlab.com/chrisabela/runit_scripts_for_slackware+----
  
   * Written for Slackware 14.2 in December 2018   * Written for Slackware 14.2 in December 2018

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