3 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
5 This file is part of systemd.
7 Copyright 2011 Lennart Poettering
9 systemd is free software; you can redistribute it and/or modify it
10 under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 2 of the License, or
12 (at your option) any later version.
14 systemd is distributed in the hope that it will be useful, but
15 WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with systemd; If not, see <http://www.gnu.org/licenses/>.
22 <refentry id="sysctl.d">
25 <title>sysctl.d</title>
26 <productname>systemd</productname>
30 <contrib>Developer</contrib>
31 <firstname>Lennart</firstname>
32 <surname>Poettering</surname>
33 <email>lennart@poettering.net</email>
39 <refentrytitle>sysctl.d</refentrytitle>
40 <manvolnum>5</manvolnum>
44 <refname>sysctl.d</refname>
45 <refpurpose>Configure kernel parameters at boot</refpurpose>
49 <para><filename>/usr/lib/sysctl.d/*.conf</filename></para>
50 <para><filename>/etc/sysctl.d/*.conf</filename></para>
51 <para><filename>/run/sysctl.d/*.conf</filename></para>
55 <title>Description</title>
57 <para><command>systemd</command> uses configuration files
58 from the above directories to configure
59 <citerefentry><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
60 kernel parameters to load during boot.</para>
64 <title>Configuration Format</title>
66 <para>The configuration files should simply contain a
67 list of variable assignments, separated by
68 newlines. Empty lines and lines whose first
69 non-whitespace character is # or ; are ignored.</para>
71 <para>Note that both / and . are accepted as
72 separators in sysctl variable names.</para>
74 <para>Each configuration file is named in the style of
75 <filename><program>.conf</filename>.
76 Files in <filename>/etc/</filename> overwrite
77 files with the same name in <filename>/usr/lib/</filename>.
78 Files in <filename>/run</filename> overwrite files with
79 the same name in <filename>/etc/</filename> and
80 <filename>/usr/lib/</filename>. Packages should install their
81 configuration files in <filename>/usr/lib/</filename>, files
82 in <filename>/etc/</filename> are reserved for the local
83 administration, which possibly decides to overwrite the
84 configurations installed from packages. All files are sorted
85 by filename in alphabetical order, regardless in which of the
86 directories they reside, to ensure that a specific
87 configuration file takes precedence over another file with
88 an alphabetically later name.</para>
92 <title>Example</title>
94 <title>/etc/sysctl.d/domain-name.conf example:</title>
96 <programlisting># Set kernel YP domain name
97 kernel.domainname=example.com</programlisting>
102 <title>See Also</title>
104 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
105 <citerefentry><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
106 <citerefentry><refentrytitle>sysctl.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>