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                         <author>
  35                                 <contrib>Developer</contrib>
  36                                 <firstname>Lennart</firstname>
  37                                 <surname>Poettering</surname>
  38                                 <email>lennart@poettering.net</email>
  39                         </author>
  40                 </authorgroup>
  41         </refentryinfo>
  42         <refmeta>
  43                 <refentrytitle>systemd-socket-proxyd</refentrytitle>
  44                 <manvolnum>1</manvolnum>
  45         </refmeta>
  46         <refnamediv>
  47                 <refname>systemd-socket-proxyd</refname>
  48                 <refpurpose>Bidirectionally proxy local sockets to another (possibly remote) socket.</refpurpose>
  49         </refnamediv>
  50         <refsynopsisdiv>
  51                 <cmdsynopsis>
  52                         <command>systemd-socket-proxyd</command>
  53                         <arg choice="opt" rep="repeat"><replaceable>OPTIONS</replaceable></arg>
  54                         <arg choice="plain"><replaceable>HOST</replaceable>:<replaceable>PORT</replaceable></arg>
  55                 </cmdsynopsis>
  56                 <cmdsynopsis>
  57                         <command>systemd-socket-proxyd</command>
  58                         <arg choice="opt" rep="repeat"><replaceable>OPTIONS</replaceable></arg>
  59                         <arg choice="plain"><replaceable>UNIX-DOMAIN-SOCKET-PATH</replaceable>
  60                         </arg>
  61                 </cmdsynopsis>
  62         </refsynopsisdiv>
  63         <refsect1>
  64                 <title>Description</title>
  65                 <para>
  66                 <command>systemd-socket-proxyd</command> is a generic
  67                 socket-activated network socket forwarder proxy daemon
  68                 for IPV4, IPv6 and UNIX stream sockets. It may be used
  69                 to bi-directionally forward traffic from a local listening socket to a
  70                 local or remote destination socket.</para>
  71
  72                 <para>One use of this tool is to provide
  73                 socket activation support for services that do not
  74                 natively support socket activation. On behalf of the
  75                 service to activate, the proxy inherits the socket
  76                 from systemd, accepts each client connection, opens a
  77                 connection to a configured server for each client, and
  78                 then bidirectionally forwards data between the
  79                 two.</para>
  80                 <para>This utility's behavior is similar to
  81                 <citerefentry><refentrytitle>socat</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
  82                 The main differences for <command>systemd-socket-proxyd</command>
  83                 are support for socket activation with
  84                 <literal>Accept=false</literal> and an event-driven
  85                 design that scales better with the number of
  86                 connections.</para>
  87         </refsect1>
  88         <refsect1>
  89                 <title>Options</title>
  90                 <para>The following options are understood:</para>
  91                 <variablelist>
  92                         <varlistentry>
  93                                 <term><option>-l</option></term>
  94                                 <term><option>--listener</option></term>
  95                                 <listitem>
  96                                         <para>Restricts listening to a
  97                                         single inherited socket, specified
  98                                         as a file descriptor. By default,
  99                                         the proxy listens on all inherited
 100                                         sockets.</para>
 101                                 </listitem>
 102                         </varlistentry>
 103                         <varlistentry>
 104                                 <term><option>-h</option></term>
 105                                 <term><option>--help</option></term>
 106                                 <listitem>
 107                                         <para>Prints a short help
 108                                         text and exits.</para>
 109                                 </listitem>
 110                         </varlistentry>
 111                         <varlistentry>
 112                                 <term><option>--version</option></term>
 113                                 <listitem>
 114                                         <para>Prints a version
 115                                         string and exits.</para>
 116                                 </listitem>
 117                         </varlistentry>
 118                 </variablelist>
 119         </refsect1>
 120         <refsect1>
 121                 <title>Exit status</title>
 122                 <para>On success, 0 is returned, a non-zero failure
 123                 code otherwise.</para>
 124         </refsect1>
 125         <refsect1>
 126                 <title>Examples</title>
 127                 <refsect2>
 128                         <title>Direct-Use Example</title>
 129                         <para>Use two services with a dependency
 130                         and no namespace isolation.</para>
 131                         <example label="proxy socket unit">
 132                                 <title>/etc/systemd/system/proxy-to-nginx.socket</title>
 133                                 <programlisting>
 134 <![CDATA[[Socket]
 135 ListenStream=80
 136
 137 [Install]
 138 WantedBy=sockets.target]]>
 139 </programlisting>
 140                         </example>
 141                         <example label="proxy service unit">
 142                                 <title>/etc/systemd/system/proxy-to-nginx.service</title>
 143                                 <programlisting>
 144 <![CDATA[[Unit]
 145 After=nginx.service
 146 Requires=nginx.service
 147
 148 [Service]
 149 ExecStart=/usr/bin/systemd-socket-proxyd /tmp/nginx.sock
 150 PrivateTmp=true
 151 PrivateNetwork=true]]>
 152 </programlisting>
 153                         </example>
 154                         <example label="nginx configuration">
 155                                 <title>/etc/nginx/nginx.conf</title>
 156                                 <programlisting>
 157 <![CDATA[[...]
 158 server {
 159     listen       unix:/tmp/nginx.sock;
 160     [...]]]>
 161 </programlisting>
 162                         </example>
 163                         <example label="commands">
 164                                 <programlisting>
 165 <![CDATA[# systemctl enable proxy-to-nginx.socket
 166 # systemctl start proxy-to-nginx.socket
 167 $ curl http://localhost:80/]]>
 168 </programlisting>
 169                         </example>
 170                 </refsect2>
 171                 <refsect2>
 172                         <title>Indirect-Use Example</title>
 173                         <para>Use a shell script to isolate the
 174                         service and proxy into the same namespace.
 175                         This is particularly useful for running
 176                         TCP-only daemons without the daemon
 177                         affecting ports on regular
 178                         interfaces.</para>
 179                         <example label="combined proxy and nginx socket unit">
 180
 181                                 <title>
 182                                 /etc/systemd/system/proxy-with-nginx.socket</title>
 183                                 <programlisting>
 184 <![CDATA[[Socket]
 185 ListenStream=80
 186
 187 [Install]
 188 WantedBy=sockets.target]]>
 189 </programlisting>
 190                         </example>
 191                         <example label="combined proxy and nginx service unit">
 192
 193                                 <title>
 194                                 /etc/systemd/system/proxy-with-nginx.service</title>
 195                                 <programlisting>
 196 <![CDATA[[Unit]
 197 After=remote-fs.target nss-lookup.target
 198
 199 [Service]
 200 ExecStartPre=/usr/sbin/nginx -t
 201 ExecStart=/usr/bin/socket-proxyd-nginx.sh
 202 PrivateTmp=true
 203 PrivateNetwork=true]]>
 204 </programlisting>
 205                         </example>
 206                         <example label="shell script">
 207                                 <title>
 208                                 /usr/bin/socket-proxyd-nginx.sh</title>
 209                                 <programlisting>
 210 <![CDATA[#!/bin/sh
 211 /usr/sbin/nginx
 212 while [ ! -f /tmp/nginx.pid ]
 213   do
 214      /usr/bin/inotifywait /tmp/nginx.pid
 215   done
 216 exec /usr/bin/systemd-socket-proxyd localhost:8080]]>
 217 </programlisting>
 218                                 <para>Make it executable:</para>
 219                                 <programlisting>
 220 <![CDATA[chmod 755 /usr/bin/socket-proxyd-nginx.sh]]>
 221                                 </programlisting>
 222                         </example>
 223                         <example label="nginx configuration">
 224                                 <title>
 225                                 /etc/nginx/nginx.conf</title>
 226                                 <programlisting>
 227 <![CDATA[[...]
 228 server {
 229     listen       8080;
 230     listen       unix:/tmp/nginx.sock;
 231     [...]]]>
 232 </programlisting>
 233                         </example>
 234                         <example label="commands">
 235                                 <programlisting>
 236 <![CDATA[# systemctl enable proxy-with-nginx.socket
 237 # systemctl start proxy-with-nginx.socket
 238 $ curl http://localhost:80/]]>
 239 </programlisting>
 240                         </example>
 241                 </refsect2>
 242
 243                 <refsect2>
 244                         <title>Multiple Listeners with Multiple Destinations</title>
 245                         <para>When using namespaces, it may be useful to
 246                         have multiple listeners with each going to a unique
 247                         destination. systemd always passes sockets into
 248                         services in the order specified in the socket
 249                         unit, beginning with file descriptor 3.</para>
 250                         <para>In this example, port <literal>80</literal>
 251                         will proxy to <literal>localhost:8080</literal>,
 252                         and port <literal>443</literal> will proxy to
 253                         <literal>localhost:8443</literal>.</para>
 254                         <example label="proxy socket unit">
 255                                 <title>/etc/systemd/system/multi-destination.socket</title>
 256                                 <programlisting>
 257 <![CDATA[[Socket]
 258 ListenStream=80
 259 ListenStream=443
 260
 261 [Install]
 262 WantedBy=sockets.target]]>
 263 </programlisting>
 264                         </example>
 265                         <example label="proxy service unit">
 266                                 <title>/etc/systemd/system/multi-destination.service</title>
 267                                 <programlisting>
 268 <![CDATA[[Service]
 269 ExecStart=/usr/bin/socket-proxyd-multi-destination.sh
 270 PrivateTmp=true
 271 PrivateNetwork=true]]>
 272 </programlisting>
 273                         </example>
 274
 275                         <example label="shell script">
 276                                 <title>
 277                                 /usr/bin/socket-proxyd-multi-destination.sh</title>
 278                                 <programlisting>
 279 <![CDATA[#!/bin/sh
 280 /usr/bin/systemd-socket-proxyd --listener=3 localhost:8080 &
 281 /usr/bin/systemd-socket-proxyd --listener=4 localhost:8443 &
 282 wait]]>
 283 </programlisting>
 284                                 <para>Make it executable:</para>
 285                                 <programlisting>
 286 <![CDATA[chmod 755 /usr/bin/socket-proxyd-multi-destination.sh]]>
 287                                 </programlisting>
 288                         </example>
 289
 290                         <example label="commands">
 291                                 <programlisting>
 292 <![CDATA[# systemctl enable multi-destination.socket
 293 # systemctl start multi-destination.socket
 294 $ curl http://localhost/
 295 $ curl https://localhost/]]>
 296 </programlisting>
 297                         </example>
 298                 </refsect2>
 299         </refsect1>
 300         <refsect1>
 301                 <title>See Also</title>
 302                 <para>
 303                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 304                         <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 305                         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 306                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 307                         <citerefentry><refentrytitle>socat</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 308                 </para>
 309         </refsect1>
 310 </refentry>