doc/runlevels.html


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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>runit - runlevels</title>
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<body>
<a href="http://smarden.org/pape/">G. Pape</a><br>
<a href="index.html">runit</a><br>
<hr>
<h1>runit - runlevels</h1>
<hr>
<a href="#prepare">Prepare runit for using runlevels</a><br>
<a href="#switch">Switching runlevels</a><br>
<a href="#create">Creating runlevels</a>
<hr>
<a name="prepare"><h3>Prepare runit</h3></a>
If not yet done, configure your system to use
<a href="runit.8.html">runit</a> as process no 1 by following the
<a href="replaceinit.html">instructions</a>.
<p>
Create the following directories and symbolic links:
<pre>
 # mkdir -p /etc/runit/runsvdir/default
 # mkdir -p /etc/runit/runsvdir/single
 # ln -s /etc/sv/getty-5 /etc/runit/runsvdir/single/
 # ln -s default /etc/runit/runsvdir/current
</pre>
Copy the contents of <tt>/service/</tt> to
<tt>/etc/runit/runsvdir/current/</tt> and replace <tt>/service/</tt>
with a symbolic link:
<pre>
 # cp -pR /service/* /etc/runit/runsvdir/current/
 # mv -f /service /service.old && \
     ln -s /etc/runit/runsvdir/current /service
</pre>
You have now created two runlevels: <tt>default</tt> and <tt>single</tt>.
The <tt>current</tt> runlevel is <tt>default</tt>.
It is safe to remove <tt>/service.old/</tt> if you don't need it anymore.
<p>
Finally edit <tt>/etc/runit/2</tt> to set the <tt>default</tt> runlevel when
stage 2 starts:
<pre>
 $ cat /etc/runit/2 
 #!/bin/sh
 PATH=/command:/usr/local/bin:/usr/local/sbin:/bin:/sbin:/usr/bin:/usr/sbin:/usr/X11R6/bin
 
 <b>runsvchdir default &gt;/dev/null</b>
 
 exec env - PATH=$PATH \
 runsvdir /service 'log: ...........................................................................................................................................................................................................................................................................................................................................................................................................'
</pre>
<hr>
<a name="switch"><h3>Switching runlevels</h3></a>
Switching runlevels with <i>runit</i> is done by switching the directory the
<a href="runsvdir.8.html">runsvdir</a> program is running in.
This is done by the <a href="runsvchdir.8.html">runsvchdir</a> program, e.g.
to switch to the <tt>single</tt> user runlevel, do:
<pre>
 # runsvchdir single
</pre>
To switch back to the <tt>default</tt> runlevel, do:
<pre>
 # runsvchdir default
</pre>
See <a href="runsvdir.8.html">the runsvdir program</a> for a description of
what happens when <i>runsvdir</i> sees the directory changed.
Note that there is no guarantee that all services from the <tt>previous</tt>
runlevel will stop, the <a href="runsv.8.html">runsv</a> processes have sent
the service daemons a SIGTERM and wait for them to terminate.
You can check the status of the <tt>previous</tt> runlevel through
<tt>/etc/runit/runsvdir/previous/</tt>.
<hr>
<a name="create"><h3>Creating new runlevels</h3></a>
To create a new runlevel, simply create a new directory in
<tt>/etc/runit/runsvdir/</tt>.
The name of the directory is the name of the new runlevel.
The name must not start with a dot and must not be <tt>current</tt>,
<tt>current.new</tt>, or <tt>previous</tt>, e.g.:
<pre>
 # mkdir /etc/runit/runsvdir/maintenance
</pre>
Add the services you want to run in the runlevel <tt>maintenance</tt> to the
newly created directory, e.g.:
<pre>
 # ln -s /etc/sv/getty-5 /etc/runit/runsvdir/maintenance/
 # ln -s /etc/sv/ssh /etc/runit/runsvdir/maintenance/
 # ln -s /etc/sv/dnscache /etc/runit/runsvdir/maintenance/
</pre>
If you want to switch to the runlevel <tt>maintenance</tt>, do:
<pre>
 # runsvchdir maintenance
</pre>
<hr>
<address><a href="mailto:pape@smarden.org">
Gerrit Pape &lt;pape@smarden.org&gt;
</a></address>
</body>
</html>