man/nss-mymachines.xml

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   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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   5 <!--
   6   SPDX-License-Identifier: LGPL-2.1+
   7
   8   Copyright 2014 Lennart Poettering
   9 -->
  10
  11 <refentry id="nss-mymachines" conditional='ENABLE_MACHINED'>
  12
  13   <refentryinfo>
  14     <title>nss-mymachines</title>
  15     <productname>systemd</productname>
  16
  17     <authorgroup>
  18       <author>
  19         <contrib>Developer</contrib>
  20         <firstname>Lennart</firstname>
  21         <surname>Poettering</surname>
  22         <email>lennart@poettering.net</email>
  23       </author>
  24     </authorgroup>
  25   </refentryinfo>
  26
  27   <refmeta>
  28     <refentrytitle>nss-mymachines</refentrytitle>
  29     <manvolnum>8</manvolnum>
  30   </refmeta>
  31
  32   <refnamediv>
  33     <refname>nss-mymachines</refname>
  34     <refname>libnss_mymachines.so.2</refname>
  35     <refpurpose>Provide hostname resolution for local
  36     container instances.</refpurpose>
  37   </refnamediv>
  38
  39   <refsynopsisdiv>
  40     <para><filename>libnss_mymachines.so.2</filename></para>
  41   </refsynopsisdiv>
  42
  43   <refsect1>
  44     <title>Description</title>
  45
  46     <para><command>nss-mymachines</command> is a plug-in module for the GNU Name Service Switch (NSS) functionality of
  47     the GNU C Library (<command>glibc</command>), providing hostname resolution for the names of containers running
  48     locally that are registered with
  49     <citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.  The
  50     container names are resolved to the IP addresses of the specific container, ordered by their scope. This
  51     functionality only applies to containers using network namespacing.</para>
  52
  53     <para>The module also resolves user and group IDs used by containers to user and group names indicating the
  54     container name, and back. This functionality only applies to containers using user namespacing.</para>
  55
  56     <para>To activate the NSS module, add <literal>mymachines</literal> to the lines starting with
  57     <literal>hosts:</literal>, <literal>passwd:</literal> and <literal>group:</literal> in
  58     <filename>/etc/nsswitch.conf</filename>.</para>
  59
  60     <para>It is recommended to place <literal>mymachines</literal> after the <literal>files</literal> or
  61     <literal>compat</literal> entry of the <filename>/etc/nsswitch.conf</filename> lines to make sure that its mappings
  62     are preferred over other resolvers such as DNS, but so that <filename>/etc/hosts</filename>,
  63     <filename>/etc/passwd</filename> and <filename>/etc/group</filename> based mappings take precedence.</para>
  64   </refsect1>
  65
  66   <refsect1>
  67     <title>Example</title>
  68
  69     <para>Here is an example <filename>/etc/nsswitch.conf</filename> file that enables
  70     <command>nss-mymachines</command> correctly:</para>
  71
  72     <programlisting>passwd:         compat <command>mymachines</command> systemd
  73 group:          compat <command>mymachines</command> systemd
  74 shadow:         compat
  75
  76 hosts:          files <command>mymachines</command> resolve [!UNAVAIL=return] dns myhostname
  77 networks:       files
  78
  79 protocols:      db files
  80 services:       db files
  81 ethers:         db files
  82 rpc:            db files
  83
  84 netgroup:       nis</programlisting>
  85
  86   </refsect1>
  87
  88   <refsect1>
  89     <title>See Also</title>
  90     <para>
  91       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  92       <citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
  93       <citerefentry><refentrytitle>nss-systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
  94       <citerefentry><refentrytitle>nss-resolve</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
  95       <citerefentry><refentrytitle>nss-myhostname</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
  96       <citerefentry project='man-pages'><refentrytitle>nsswitch.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  97       <citerefentry project='man-pages'><refentrytitle>getent</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  98     </para>
  99   </refsect1>
 100
 101 </refentry>