chiark / gitweb /
sysctl: replaces some slashes with dots
[elogind.git] / man / sysctl.d.xml
index 8f336dc..db53b49 100644 (file)
@@ -7,16 +7,16 @@
   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
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 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.
+  Lesser General Public License for more details.
 
-  You should have received a copy of the GNU General Public License
+  You should have received a copy of the GNU Lesser General Public License
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 -->
 <refentry id="sysctl.d">
 
         <refsynopsisdiv>
                 <para><filename>/etc/sysctl.d/*.conf</filename></para>
+                <para><filename>/run/sysctl.d/*.conf</filename></para>
+                <para><filename>/usr/lib/sysctl.d/*.conf</filename></para>
         </refsynopsisdiv>
 
         <refsect1>
                 <title>Description</title>
 
-               <para><command>systemd</command> uses
-               <filename>/etc/sysctl.d/</filename> to configure
-               <citerefentry><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
-               kernel parameters to load during boot. Each
-               configuration file is named in the style of
-               <filename>/etc/sysctl.d/&lt;program&gt;.conf</filename>.</para>
+                <para>At boot,
+                <citerefentry><refentrytitle>systemd-sysctl.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+                reads configuration files from the above directories
+                to configure
+                <citerefentry><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+                kernel parameters.</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>
+                <title>Configuration Format</title>
+
+                <para>The configuration files contain a list of
+                variable assignments, separated by newlines. Empty
+                lines and lines whose first non-whitespace character
+                is <literal>#</literal> or <literal>;</literal> are
+                ignored.</para>
+
+                <para>Note that either <literal>/</literal> or
+                <literal>.</literal> may be used as separators within
+                sysctl variable names. If the first separator is a
+                slash, remaining slashes and dots are left intact. If
+                the first separator is a dot, dots and slashes are
+                interchanged. <literal>kernel.domainname=foo</literal>
+                and <literal>kernel/domainname=foo</literal> are
+                equivalent and will cause <literal>foo</literal> to
+                be written to
+                <filename>/proc/sys/kernel/domainname</filename>.
+                Either
+                <literal>net.ipv4.conf.enp3s0/200.forwarding</literal>
+                or
+                <literal>net/ipv4/conf/enp3s0.200/forwarding</literal>
+                may be used to refer to
+                <filename>/proc/sys/net/ipv4/conf/enp3s0.200/forwarding</filename>.
+                </para>
 
+                <para>Each configuration file shall be named in the
+                style of <filename><replaceable>program</replaceable>.conf</filename>.
+                Files in <filename>/etc/</filename> override files
+                with the same name in <filename>/usr/lib/</filename>
+                and <filename>/run/</filename>.  Files in
+                <filename>/run/</filename> override files with the same
+                name in <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
+                administrator, who may use this logic to override the
+                configuration files installed by vendor packages. All
+                configuration files are sorted by their filename in
+                lexicographic order, regardless of which of the
+                directories they reside in. If multiple files specify the
+                same variable name, the entry in the file with the
+                lexicographically latest name will be applied. It is
+                recommended to prefix all filenames with a two-digit
+                number and a dash, to simplify the ordering of the
+                files.</para>
+
+                <para>If the administrator wants to disable a
+                configuration file supplied by the vendor, the
+                recommended way is to place a symlink to
+                <filename>/dev/null</filename> in
+                <filename>/etc/sysctl.d/</filename> bearing the
+                same filename.</para>
+
+                <para>The settings configured with
+                <filename>sysctl.d</filename> files will be applied
+                early on boot. The network interface-specific options
+                will also be applied individually for each network
+                interface as it shows up in the system. (More
+                specifically,
+                <filename>net.ipv4.conf.*</filename>,
+                <filename>net.ipv6.conf.*</filename>,
+                <filename>net.ipv4.neigh.*</filename> and <filename>net.ipv6.neigh.*</filename>)</para>
         </refsect1>
 
         <refsect1>
@@ -87,6 +142,8 @@ kernel.domainname=example.com</programlisting>
                 <title>See Also</title>
                 <para>
                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+                        <citerefentry><refentrytitle>systemd-sysctl.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+                        <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
                         <citerefentry><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
                         <citerefentry><refentrytitle>sysctl.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
                 </para>