man/systemd-socket-proxyd.xml

   1 <?xml version="1.0"?>
   2 <!--*-nxml-*-->
   3 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   4      "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   5 <!--
   6   SPDX-License-Identifier: LGPL-2.1+
   7
   8   This file is part of systemd.
   9
  10   Copyright 2013 David Strauss
  11
  12   systemd is free software; you can redistribute it and/or modify it
  13   under the terms of the GNU Lesser General Public License as published by
  14   the Free Software Foundation; either version 2.1 of the License, or
  15   (at your option) any later version.
  16
  17   systemd is distributed in the hope that it will be useful, but
  18   WITHOUT ANY WARRANTY; without even the implied warranty of
  19   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  20   Lesser General Public License for more details.
  21
  22   You should have received a copy of the GNU Lesser General Public License
  23   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  24 -->
  25 <refentry id="systemd-socket-proxyd"
  26     xmlns:xi="http://www.w3.org/2001/XInclude">
  27
  28   <refentryinfo>
  29     <title>systemd-socket-proxyd</title>
  30     <productname>systemd</productname>
  31     <authorgroup>
  32       <author>
  33         <contrib>Developer</contrib>
  34         <firstname>David</firstname>
  35         <surname>Strauss</surname>
  36         <email>david@davidstrauss.net</email>
  37       </author>
  38     </authorgroup>
  39   </refentryinfo>
  40   <refmeta>
  41     <refentrytitle>systemd-socket-proxyd</refentrytitle>
  42     <manvolnum>8</manvolnum>
  43   </refmeta>
  44   <refnamediv>
  45     <refname>systemd-socket-proxyd</refname>
  46     <refpurpose>Bidirectionally proxy local sockets to another (possibly remote) socket.</refpurpose>
  47   </refnamediv>
  48   <refsynopsisdiv>
  49     <cmdsynopsis>
  50       <command>systemd-socket-proxyd</command>
  51       <arg choice="opt" rep="repeat"><replaceable>OPTIONS</replaceable></arg>
  52       <arg choice="plain"><replaceable>HOST</replaceable>:<replaceable>PORT</replaceable></arg>
  53     </cmdsynopsis>
  54     <cmdsynopsis>
  55       <command>systemd-socket-proxyd</command>
  56       <arg choice="opt" rep="repeat"><replaceable>OPTIONS</replaceable></arg>
  57       <arg choice="plain"><replaceable>UNIX-DOMAIN-SOCKET-PATH</replaceable>
  58       </arg>
  59     </cmdsynopsis>
  60   </refsynopsisdiv>
  61   <refsect1>
  62     <title>Description</title>
  63     <para>
  64     <command>systemd-socket-proxyd</command> is a generic
  65     socket-activated network socket forwarder proxy daemon for IPv4,
  66     IPv6 and UNIX stream sockets. It may be used to bi-directionally
  67     forward traffic from a local listening socket to a local or remote
  68     destination socket.</para>
  69
  70     <para>One use of this tool is to provide socket activation support
  71     for services that do not natively support socket activation. On
  72     behalf of the service to activate, the proxy inherits the socket
  73     from systemd, accepts each client connection, opens a connection
  74     to a configured server for each client, and then bidirectionally
  75     forwards data between the two.</para>
  76     <para>This utility's behavior is similar to
  77     <citerefentry project='die-net'><refentrytitle>socat</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
  78     The main differences for <command>systemd-socket-proxyd</command>
  79     are support for socket activation with
  80     <literal>Accept=false</literal> and an event-driven
  81     design that scales better with the number of
  82     connections.</para>
  83   </refsect1>
  84   <refsect1>
  85     <title>Options</title>
  86     <para>The following options are understood:</para>
  87     <variablelist>
  88       <xi:include href="standard-options.xml" xpointer="help" />
  89       <xi:include href="standard-options.xml" xpointer="version" />
  90       <varlistentry>
  91         <term><option>--connections-max=</option></term>
  92         <term><option>-c</option></term>
  93
  94         <listitem><para>Sets the maximum number of simultaneous connections, defaults to 256.
  95         If the limit of concurrent connections is reached further connections will be refused.</para></listitem>
  96       </varlistentry>
  97     </variablelist>
  98   </refsect1>
  99   <refsect1>
 100     <title>Exit status</title>
 101     <para>On success, 0 is returned, a non-zero failure
 102     code otherwise.</para>
 103   </refsect1>
 104   <refsect1>
 105     <title>Examples</title>
 106     <refsect2>
 107       <title>Simple Example</title>
 108       <para>Use two services with a dependency and no namespace
 109       isolation.</para>
 110       <example>
 111         <title>proxy-to-nginx.socket</title>
 112         <programlisting><![CDATA[[Socket]
 113 ListenStream=80
 114
 115 [Install]
 116 WantedBy=sockets.target]]></programlisting>
 117       </example>
 118       <example>
 119         <title>proxy-to-nginx.service</title>
 120         <programlisting><![CDATA[[Unit]
 121 Requires=nginx.service
 122 After=nginx.service
 123 Requires=proxy-to-nginx.socket
 124 After=proxy-to-nginx.socket
 125
 126 [Service]
 127 ExecStart=/usr/lib/systemd/systemd-socket-proxyd /tmp/nginx.sock
 128 PrivateTmp=yes
 129 PrivateNetwork=yes]]></programlisting>
 130       </example>
 131       <example>
 132         <title>nginx.conf</title>
 133         <programlisting>
 134 <![CDATA[[…]
 135 server {
 136     listen       unix:/tmp/nginx.sock;
 137     […]]]>
 138 </programlisting>
 139       </example>
 140       <example>
 141         <title>Enabling the proxy</title>
 142         <programlisting><![CDATA[# systemctl enable --now proxy-to-nginx.socket
 143 $ curl http://localhost:80/]]></programlisting>
 144       </example>
 145     </refsect2>
 146     <refsect2>
 147       <title>Namespace Example</title>
 148       <para>Similar as above, but runs the socket proxy and the main
 149       service in the same private namespace, assuming that
 150       <filename>nginx.service</filename> has
 151       <varname>PrivateTmp=</varname> and
 152       <varname>PrivateNetwork=</varname> set, too.</para>
 153       <example>
 154         <title>proxy-to-nginx.socket</title>
 155         <programlisting><![CDATA[[Socket]
 156 ListenStream=80
 157
 158 [Install]
 159 WantedBy=sockets.target]]></programlisting>
 160       </example>
 161       <example>
 162         <title>proxy-to-nginx.service</title>
 163         <programlisting><![CDATA[[Unit]
 164 Requires=nginx.service
 165 After=nginx.service
 166 Requires=proxy-to-nginx.socket
 167 After=proxy-to-nginx.socket
 168 JoinsNamespaceOf=nginx.service
 169
 170 [Service]
 171 ExecStart=/usr/lib/systemd/systemd-socket-proxyd 127.0.0.1:8080
 172 PrivateTmp=yes
 173 PrivateNetwork=yes]]></programlisting>
 174       </example>
 175       <example>
 176         <title>nginx.conf</title>
 177         <programlisting><![CDATA[[…]
 178 server {
 179     listen       8080;
 180     […]]]></programlisting>
 181       </example>
 182       <example>
 183         <title>Enabling the proxy</title>
 184         <programlisting><![CDATA[# systemctl enable --now proxy-to-nginx.socket
 185 $ curl http://localhost:80/]]></programlisting>
 186       </example>
 187     </refsect2>
 188   </refsect1>
 189   <refsect1>
 190     <title>See Also</title>
 191     <para>
 192       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 193       <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 194       <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 195       <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 196       <citerefentry project='die-net'><refentrytitle>socat</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 197       <citerefentry project='die-net'><refentrytitle>nginx</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 198       <citerefentry project='die-net'><refentrytitle>curl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 199     </para>
 200   </refsect1>
 201 </refentry>