man/systemd-socket-proxyd.xml

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   8   Copyright 2013 David Strauss
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  23 <refentry id="systemd-socket-proxyd">
  24         <refentryinfo>
  25                 <title>systemd-socket-proxyd</title>
  26                 <productname>systemd</productname>
  27                 <authorgroup>
  28                         <author>
  29                                 <contrib>Developer</contrib>
  30                                 <firstname>David</firstname>
  31                                 <surname>Strauss</surname>
  32                                 <email>david@davidstrauss.net</email>
  33                         </author>
  34                 </authorgroup>
  35         </refentryinfo>
  36         <refmeta>
  37                 <refentrytitle>systemd-socket-proxyd</refentrytitle>
  38                 <manvolnum>1</manvolnum>
  39         </refmeta>
  40         <refnamediv>
  41                 <refname>systemd-socket-proxyd</refname>
  42                 <refpurpose>Bidirectionally proxy local sockets to another (possibly remote) socket.</refpurpose>
  43         </refnamediv>
  44         <refsynopsisdiv>
  45                 <cmdsynopsis>
  46                         <command>systemd-socket-proxyd</command>
  47                         <arg choice="opt" rep="repeat"><replaceable>OPTIONS</replaceable></arg>
  48                         <arg choice="plain"><replaceable>HOST</replaceable>:<replaceable>PORT</replaceable></arg>
  49                 </cmdsynopsis>
  50                 <cmdsynopsis>
  51                         <command>systemd-socket-proxyd</command>
  52                         <arg choice="opt" rep="repeat"><replaceable>OPTIONS</replaceable></arg>
  53                         <arg choice="plain"><replaceable>UNIX-DOMAIN-SOCKET-PATH</replaceable>
  54                         </arg>
  55                 </cmdsynopsis>
  56         </refsynopsisdiv>
  57         <refsect1>
  58                 <title>Description</title>
  59                 <para>
  60                 <command>systemd-socket-proxyd</command> is a generic
  61                 socket-activated network socket forwarder proxy daemon
  62                 for IPV4, IPv6 and UNIX stream sockets. It may be used
  63                 to bi-directionally forward traffic from a local listening socket to a
  64                 local or remote destination socket.</para>
  65
  66                 <para>One use of this tool is to provide
  67                 socket activation support for services that do not
  68                 natively support socket activation. On behalf of the
  69                 service to activate, the proxy inherits the socket
  70                 from systemd, accepts each client connection, opens a
  71                 connection to a configured server for each client, and
  72                 then bidirectionally forwards data between the
  73                 two.</para>
  74                 <para>This utility's behavior is similar to
  75                 <citerefentry><refentrytitle>socat</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
  76                 The main differences for <command>systemd-socket-proxyd</command>
  77                 are support for socket activation with
  78                 <literal>Accept=false</literal> and an event-driven
  79                 design that scales better with the number of
  80                 connections.</para>
  81         </refsect1>
  82         <refsect1>
  83                 <title>Options</title>
  84                 <para>The following options are understood:</para>
  85                 <variablelist>
  86                         <varlistentry>
  87                                 <term><option>-h</option></term>
  88                                 <term><option>--help</option></term>
  89                                 <listitem>
  90                                         <para>Prints a short help
  91                                         text and exits.</para>
  92                                 </listitem>
  93                         </varlistentry>
  94                         <varlistentry>
  95                                 <term><option>--version</option></term>
  96                                 <listitem>
  97                                         <para>Prints a version
  98                                         string and exits.</para>
  99                                 </listitem>
 100                         </varlistentry>
 101                 </variablelist>
 102         </refsect1>
 103         <refsect1>
 104                 <title>Exit status</title>
 105                 <para>On success, 0 is returned, a non-zero failure
 106                 code otherwise.</para>
 107         </refsect1>
 108         <refsect1>
 109                 <title>Examples</title>
 110                 <refsect2>
 111                         <title>Direct-Use Example</title>
 112                         <para>Use two services with a dependency
 113                         and no namespace isolation.</para>
 114                         <example label="proxy socket unit">
 115                                 <title>/etc/systemd/system/proxy-to-nginx.socket</title>
 116                                 <programlisting>
 117 <![CDATA[[Socket]
 118 ListenStream=80
 119
 120 [Install]
 121 WantedBy=sockets.target]]>
 122 </programlisting>
 123                         </example>
 124                         <example label="proxy service unit">
 125                                 <title>/etc/systemd/system/proxy-to-nginx.service</title>
 126                                 <programlisting>
 127 <![CDATA[[Unit]
 128 After=nginx.service
 129 Requires=nginx.service
 130
 131 [Service]
 132 ExecStart=/usr/bin/systemd-socket-proxyd /tmp/nginx.sock
 133 PrivateTmp=true
 134 PrivateNetwork=true]]>
 135 </programlisting>
 136                         </example>
 137                         <example label="nginx configuration">
 138                                 <title>/etc/nginx/nginx.conf</title>
 139                                 <programlisting>
 140 <![CDATA[[...]
 141 server {
 142     listen       unix:/tmp/nginx.sock;
 143     [...]]]>
 144 </programlisting>
 145                         </example>
 146                         <example label="commands">
 147                                 <programlisting>
 148 <![CDATA[# systemctl --system daemon-reload
 149 # systemctl start proxy-to-nginx.socket
 150 # systemctl enable proxy-to-nginx.socket
 151 $ curl http://localhost:80/]]>
 152 </programlisting>
 153                         </example>
 154                 </refsect2>
 155                 <refsect2>
 156                         <title>Indirect-Use Example</title>
 157                         <para>Use a shell script to isolate the
 158                         service and proxy into the same namespace.
 159                         This is particularly useful for running
 160                         TCP-only daemons without the daemon
 161                         affecting ports on regular
 162                         interfaces.</para>
 163                         <example label="combined proxy and nginx socket unit">
 164
 165                                 <title>
 166                                 /etc/systemd/system/proxy-with-nginx.socket</title>
 167                                 <programlisting>
 168 <![CDATA[[Socket]
 169 ListenStream=80
 170
 171 [Install]
 172 WantedBy=sockets.target]]>
 173 </programlisting>
 174                         </example>
 175                         <example label="combined proxy and nginx service unit">
 176
 177                                 <title>
 178                                 /etc/systemd/system/proxy-with-nginx.service</title>
 179                                 <programlisting>
 180 <![CDATA[[Unit]
 181 After=syslog.target remote-fs.target nss-lookup.target
 182
 183 [Service]
 184 ExecStartPre=/usr/sbin/nginx -t
 185 ExecStart=/usr/bin/socket-proxyd-nginx.sh
 186 PrivateTmp=true
 187 PrivateNetwork=true]]>
 188 </programlisting>
 189                         </example>
 190                         <example label="shell script">
 191                                 <title>
 192                                 /usr/bin/socket-proxyd-nginx.sh</title>
 193                                 <programlisting>
 194 <![CDATA[#!/bin/sh
 195 /usr/sbin/nginx
 196 while [ ! -f /tmp/nginx.pid ]
 197   do
 198      /usr/bin/inotifywait /tmp/nginx.pid
 199   done
 200 exec /usr/bin/systemd-socket-proxyd localhost 8080]]>
 201 </programlisting>
 202                         </example>
 203                         <example label="nginx configuration">
 204                                 <title>
 205                                 /etc/nginx/nginx.conf</title>
 206                                 <programlisting>
 207 <![CDATA[[...]
 208 server {
 209     listen       8080;
 210     listen       unix:/tmp/nginx.sock;
 211     [...]]]>
 212 </programlisting>
 213                         </example>
 214                         <example label="commands">
 215                                 <programlisting>
 216 <![CDATA[# systemctl --system daemon-reload
 217 # systemctl start proxy-with-nginx.socket
 218 # systemctl enable proxy-with-nginx.socket
 219 $ curl http://localhost:80/]]>
 220 </programlisting>
 221                         </example>
 222                 </refsect2>
 223         </refsect1>
 224         <refsect1>
 225                 <title>See Also</title>
 226                 <para>
 227                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 228                         <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 229                         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 230                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 231                         <citerefentry><refentrytitle>socat</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 232                 </para>
 233         </refsect1>
 234 </refentry>