man/systemd-socket-proxyd.xml

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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>8</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>Simple Example</title>
 112                         <para>Use two services with a dependency
 113                         and no namespace isolation.</para>
 114                         <example>
 115                                 <title>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>
 125                                 <title>proxy-to-nginx.service</title>
 126                                 <programlisting>
 127 <![CDATA[[Unit]
 128 Requires=nginx.service
 129 After=nginx.service
 130
 131 [Service]
 132 ExecStart=/usr/lib/systemd/systemd-socket-proxyd /tmp/nginx.sock
 133 PrivateTmp=yes
 134 PrivateNetwork=yes]]>
 135 </programlisting>
 136                         </example>
 137                         <example>
 138                                 <title>nginx.conf</title>
 139                                 <programlisting>
 140 <![CDATA[[...]
 141 server {
 142     listen       unix:/tmp/nginx.sock;
 143     [...]]]>
 144 </programlisting>
 145                         </example>
 146                         <example>
 147                                 <title>Enabling the proxy</title>
 148                                 <programlisting>
 149 <![CDATA[# systemctl enable proxy-to-nginx.socket
 150 # systemctl start proxy-to-nginx.socket
 151 $ curl http://localhost:80/]]>
 152 </programlisting>
 153                         </example>
 154                 </refsect2>
 155                 <refsect2>
 156                         <title>Namespace Example</title>
 157                         <para>Similar as above, but runs the socket
 158                         proxy and the main service in the same private
 159                         namespace, assuming that
 160                         <filename>nginx.service</filename> has
 161                         <varname>PrivateTmp=</varname> and
 162                         <varname>PrivateNetwork=</varname> set,
 163                         too.</para>
 164                         <example>
 165                                 <title>proxy-to-nginx.socket</title>
 166                                 <programlisting>
 167 <![CDATA[[Socket]
 168 ListenStream=80
 169
 170 [Install]
 171 WantedBy=sockets.target]]>
 172 </programlisting>
 173                         </example>
 174                         <example>
 175                                 <title>proxy-to-nginx.service</title>
 176                                 <programlisting>
 177 <![CDATA[[Unit]
 178 Requires=nginx.service
 179 After=nginx.service
 180 JoinsNamespaceOf=nginx.service
 181
 182 [Service]
 183 ExecStart=/usr/lib/systemd/systemd-socket-proxyd 127.0.0.1:8080
 184 PrivateTmp=yes
 185 PrivateNetwork=yes]]>
 186 </programlisting>
 187                         </example>
 188                         <example>
 189                                 <title>nginx.conf</title>
 190                                 <programlisting>
 191 <![CDATA[[...]
 192 server {
 193     listen       8080;
 194     listen       unix:/tmp/nginx.sock;
 195     [...]]]>
 196 </programlisting>
 197                         </example>
 198                         <example>
 199                                 <title>Enabling the proxy</title>
 200                                 <programlisting>
 201 <![CDATA[# systemctl enable proxy-to-nginx.socket
 202 # systemctl start proxy-to-nginx.socket
 203 $ curl http://localhost:80/]]>
 204 </programlisting>
 205                         </example>
 206                 </refsect2>
 207         </refsect1>
 208         <refsect1>
 209                 <title>See Also</title>
 210                 <para>
 211                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 212                         <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 213                         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 214                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 215                         <citerefentry><refentrytitle>socat</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 216                         <citerefentry><refentrytitle>nginx</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 217                         <citerefentry><refentrytitle>curl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 218                 </para>
 219         </refsect1>
 220 </refentry>