mirror of
https://github.com/systemd/systemd.git
synced 2024-11-05 06:52:22 +03:00
203 lines
9.6 KiB
XML
203 lines
9.6 KiB
XML
<?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 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
|
|
Lesser General Public License for more details.
|
|
|
|
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">
|
|
|
|
<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>/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>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 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>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>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>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>
|
|
|
|
<para>Many sysctl parameters only become available
|
|
when certain kernel modules are loaded. Modules are
|
|
usually loaded on demand, e.g. when certain hardware
|
|
is plugged in or network brought up. This means that
|
|
<citerefentry><refentrytitle>systemd-sysctl.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> which runs
|
|
during early boot will not configure such parameters
|
|
if they become available after it has run. To
|
|
set such parameters, it is recommended to add
|
|
an <citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry> rule to set those parameters when they become
|
|
available. Alternatively, a slightly simpler and
|
|
less efficient option is to add the module to
|
|
<citerefentry><refentrytitle>modules-load.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>, causing it to be loaded statically
|
|
before sysctl settings are applied (see
|
|
example below).</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Examples</title>
|
|
<example>
|
|
<title>Set kernel YP domain name</title>
|
|
<para><filename>/etc/sysctl.d/domain-name.conf</filename>:
|
|
</para>
|
|
|
|
<programlisting>kernel.domainname=example.com</programlisting>
|
|
</example>
|
|
|
|
<example>
|
|
<title>Disable packet filter on bridged packets (method one)</title>
|
|
<para><filename>/etc/udev/rules.d/99-bridge.conf</filename>:
|
|
</para>
|
|
|
|
<programlisting>ACTION=="add", SUBSYSTEM=="module", KERNEL=="bridge", RUN+="/usr/lib/systemd/systemd-sysctl --prefix=/proc/sys/net/bridge"
|
|
</programlisting>
|
|
|
|
<para><filename>/etc/sysctl.d/bridge.conf</filename>:
|
|
</para>
|
|
|
|
<programlisting>net.bridge.bridge-nf-call-ip6tables = 0
|
|
net.bridge.bridge-nf-call-iptables = 0
|
|
net.bridge.bridge-nf-call-arptables = 0
|
|
</programlisting>
|
|
</example>
|
|
|
|
<example>
|
|
<title>Disable packet filter on bridged packets (method two)</title>
|
|
<para><filename>/etc/modules-load.d/bridge.conf</filename>:
|
|
</para>
|
|
|
|
<programlisting>bridge</programlisting>
|
|
|
|
<para><filename>/etc/sysctl.d/bridge.conf</filename>:
|
|
</para>
|
|
|
|
<programlisting>net.bridge.bridge-nf-call-ip6tables = 0
|
|
net.bridge.bridge-nf-call-iptables = 0
|
|
net.bridge.bridge-nf-call-arptables = 0
|
|
</programlisting>
|
|
</example>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<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>
|
|
<citerefentry><refentrytitle>modprobe</refentrytitle><manvolnum>8</manvolnum></citerefentry>
|
|
</para>
|
|
</refsect1>
|
|
|
|
</refentry>
|