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><![CDATA[[Socket]
 117 ListenStream=80
 118
 119 [Install]
 120 WantedBy=sockets.target]]></programlisting>
 121                         </example>
 122                         <example>
 123                                 <title>proxy-to-nginx.service</title>
 124                                 <programlisting><![CDATA[[Unit]
 125 Requires=nginx.service
 126 After=nginx.service
 127
 128 [Service]
 129 ExecStart=/usr/lib/systemd/systemd-socket-proxyd /tmp/nginx.sock
 130 PrivateTmp=yes
 131 PrivateNetwork=yes]]></programlisting>
 132                         </example>
 133                         <example>
 134                                 <title>nginx.conf</title>
 135                                 <programlisting>
 136 <![CDATA[[...]
 137 server {
 138     listen       unix:/tmp/nginx.sock;
 139     [...]]]>
 140 </programlisting>
 141                         </example>
 142                         <example>
 143                                 <title>Enabling the proxy</title>
 144                                 <programlisting><![CDATA[# systemctl enable proxy-to-nginx.socket
 145 # systemctl start proxy-to-nginx.socket
 146 $ curl http://localhost:80/]]></programlisting>
 147                         </example>
 148                 </refsect2>
 149                 <refsect2>
 150                         <title>Namespace Example</title>
 151                         <para>Similar as above, but runs the socket
 152                         proxy and the main service in the same private
 153                         namespace, assuming that
 154                         <filename>nginx.service</filename> has
 155                         <varname>PrivateTmp=</varname> and
 156                         <varname>PrivateNetwork=</varname> set,
 157                         too.</para>
 158                         <example>
 159                                 <title>proxy-to-nginx.socket</title>
 160                                 <programlisting><![CDATA[[Socket]
 161 ListenStream=80
 162
 163 [Install]
 164 WantedBy=sockets.target]]></programlisting>
 165                         </example>
 166                         <example>
 167                                 <title>proxy-to-nginx.service</title>
 168                                 <programlisting><![CDATA[[Unit]
 169 Requires=nginx.service
 170 After=nginx.service
 171 JoinsNamespaceOf=nginx.service
 172
 173 [Service]
 174 ExecStart=/usr/lib/systemd/systemd-socket-proxyd 127.0.0.1:8080
 175 PrivateTmp=yes
 176 PrivateNetwork=yes]]></programlisting>
 177                         </example>
 178                         <example>
 179                                 <title>nginx.conf</title>
 180                                 <programlisting><![CDATA[[...]
 181 server {
 182     listen       8080;
 183     listen       unix:/tmp/nginx.sock;
 184     [...]]]></programlisting>
 185                         </example>
 186                         <example>
 187                                 <title>Enabling the proxy</title>
 188                                 <programlisting><![CDATA[# systemctl enable proxy-to-nginx.socket
 189 # systemctl start proxy-to-nginx.socket
 190 $ curl http://localhost:80/]]></programlisting>
 191                         </example>
 192                 </refsect2>
 193         </refsect1>
 194         <refsect1>
 195                 <title>See Also</title>
 196                 <para>
 197                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 198                         <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 199                         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 200                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 201                         <citerefentry><refentrytitle>socat</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 202                         <citerefentry><refentrytitle>nginx</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 203                         <citerefentry><refentrytitle>curl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 204                 </para>
 205         </refsect1>
 206 </refentry>