<?xml version="1.0"?> <!--*-nxml-*--> <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> <!-- This file is part of systemd. Copyright 2011 Lennart Poettering systemd is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. systemd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. --> <refentry id="sysctl.d"> <refentryinfo> <title>sysctl.d</title> <productname>systemd</productname> <authorgroup> <author> <contrib>Developer</contrib> <firstname>Lennart</firstname> <surname>Poettering</surname> <email>lennart@poettering.net</email> </author> </authorgroup> </refentryinfo> <refmeta> <refentrytitle>sysctl.d</refentrytitle> <manvolnum>5</manvolnum> </refmeta> <refnamediv> <refname>sysctl.d</refname> <refpurpose>Configure kernel parameters at boot</refpurpose> </refnamediv> <refsynopsisdiv> <para><filename>/usr/lib/sysctl.d/*.conf</filename></para> <para><filename>/etc/sysctl.d/*.conf</filename></para> <para><filename>/run/sysctl.d/*.conf</filename></para> </refsynopsisdiv> <refsect1> <title>Description</title> <para><command>systemd</command> uses configuration files from the above directories to configure <citerefentry><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry> kernel parameters to load during boot.</para> </refsect1> <refsect1> <title>Configuration Format</title> <para>The configuration files should simply contain a list of variable assignments, separated by newlines. Empty lines and lines whose first non-whitespace character is # or ; are ignored.</para> <para>Note that both / and . are accepted as separators in sysctl variable names.</para> <para>Each configuration file is named in the style of <filename><program>.conf</filename>. Files in <filename>/etc/</filename> overwrite files with the same name in <filename>/usr/lib/</filename>. Files in <filename>/run</filename> overwrite files with the same name in <filename>/etc/</filename> and <filename>/usr/lib/</filename>. Packages should install their configuration files in <filename>/usr/lib/</filename>, files in <filename>/etc/</filename> are reserved for the local administration, which possibly decides to overwrite the configurations installed from packages. All files are sorted by filename in alphabetical order, regardless in which of the directories they reside, to ensure that a specific configuration file takes precedence over another file with an alphabetically later name.</para> </refsect1> <refsect1> <title>Example</title> <example> <title>/etc/sysctl.d/domain-name.conf example:</title> <programlisting># Set kernel YP domain name kernel.domainname=example.com</programlisting> </example> </refsect1> <refsect1> <title>See Also</title> <para> <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, <citerefentry><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>, <citerefentry><refentrytitle>sysctl.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> </para> </refsect1> </refentry>