man/nss-mymachines.xml

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   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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   5 <!--
   6   SPDX-License-Identifier: LGPL-2.1+
   7
   8   This file is part of systemd.
   9
  10   Copyright 2014 Lennart Poettering
  11 -->
  12
  13 <refentry id="nss-mymachines" conditional='ENABLE_MACHINED'>
  14
  15   <refentryinfo>
  16     <title>nss-mymachines</title>
  17     <productname>systemd</productname>
  18
  19     <authorgroup>
  20       <author>
  21         <contrib>Developer</contrib>
  22         <firstname>Lennart</firstname>
  23         <surname>Poettering</surname>
  24         <email>lennart@poettering.net</email>
  25       </author>
  26     </authorgroup>
  27   </refentryinfo>
  28
  29   <refmeta>
  30     <refentrytitle>nss-mymachines</refentrytitle>
  31     <manvolnum>8</manvolnum>
  32   </refmeta>
  33
  34   <refnamediv>
  35     <refname>nss-mymachines</refname>
  36     <refname>libnss_mymachines.so.2</refname>
  37     <refpurpose>Provide hostname resolution for local
  38     container instances.</refpurpose>
  39   </refnamediv>
  40
  41   <refsynopsisdiv>
  42     <para><filename>libnss_mymachines.so.2</filename></para>
  43   </refsynopsisdiv>
  44
  45   <refsect1>
  46     <title>Description</title>
  47
  48     <para><command>nss-mymachines</command> is a plug-in module for the GNU Name Service Switch (NSS) functionality of
  49     the GNU C Library (<command>glibc</command>), providing hostname resolution for the names of containers running
  50     locally that are registered with
  51     <citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.  The
  52     container names are resolved to the IP addresses of the specific container, ordered by their scope. This
  53     functionality only applies to containers using network namespacing.</para>
  54
  55     <para>The module also resolves user and group IDs used by containers to user and group names indicating the
  56     container name, and back. This functionality only applies to containers using user namespacing.</para>
  57
  58     <para>To activate the NSS module, add <literal>mymachines</literal> to the lines starting with
  59     <literal>hosts:</literal>, <literal>passwd:</literal> and <literal>group:</literal> in
  60     <filename>/etc/nsswitch.conf</filename>.</para>
  61
  62     <para>It is recommended to place <literal>mymachines</literal> after the <literal>files</literal> or
  63     <literal>compat</literal> entry of the <filename>/etc/nsswitch.conf</filename> lines to make sure that its mappings
  64     are preferred over other resolvers such as DNS, but so that <filename>/etc/hosts</filename>,
  65     <filename>/etc/passwd</filename> and <filename>/etc/group</filename> based mappings take precedence.</para>
  66   </refsect1>
  67
  68   <refsect1>
  69     <title>Example</title>
  70
  71     <para>Here is an example <filename>/etc/nsswitch.conf</filename> file that enables
  72     <command>nss-mymachines</command> correctly:</para>
  73
  74     <programlisting>passwd:         compat <command>mymachines</command> systemd
  75 group:          compat <command>mymachines</command> systemd
  76 shadow:         compat
  77
  78 hosts:          files <command>mymachines</command> resolve [!UNAVAIL=return] dns myhostname
  79 networks:       files
  80
  81 protocols:      db files
  82 services:       db files
  83 ethers:         db files
  84 rpc:            db files
  85
  86 netgroup:       nis</programlisting>
  87
  88   </refsect1>
  89
  90   <refsect1>
  91     <title>See Also</title>
  92     <para>
  93       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  94       <citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
  95       <citerefentry><refentrytitle>nss-systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
  96       <citerefentry><refentrytitle>nss-resolve</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
  97       <citerefentry><refentrytitle>nss-myhostname</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
  98       <citerefentry project='man-pages'><refentrytitle>nsswitch.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  99       <citerefentry project='man-pages'><refentrytitle>getent</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 100     </para>
 101   </refsect1>
 102
 103 </refentry>