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">
   4
   5 <!--
   6   SPDX-License-Identifier: LGPL-2.1+
   7 -->
   8
   9 <refentry id="nss-mymachines" conditional='ENABLE_NSS_MYMACHINES'>
  10
  11   <refentryinfo>
  12     <title>nss-mymachines</title>
  13     <productname>systemd</productname>
  14   </refentryinfo>
  15
  16   <refmeta>
  17     <refentrytitle>nss-mymachines</refentrytitle>
  18     <manvolnum>8</manvolnum>
  19   </refmeta>
  20
  21   <refnamediv>
  22     <refname>nss-mymachines</refname>
  23     <refname>libnss_mymachines.so.2</refname>
  24     <refpurpose>Provide hostname resolution for local
  25     container instances.</refpurpose>
  26   </refnamediv>
  27
  28   <refsynopsisdiv>
  29     <para><filename>libnss_mymachines.so.2</filename></para>
  30   </refsynopsisdiv>
  31
  32   <refsect1>
  33     <title>Description</title>
  34
  35     <para><command>nss-mymachines</command> is a plug-in module for the GNU Name Service Switch (NSS) functionality of
  36     the GNU C Library (<command>glibc</command>), providing hostname resolution for the names of containers running
  37     locally that are registered with
  38     <citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.  The
  39     container names are resolved to the IP addresses of the specific container, ordered by their scope. This
  40     functionality only applies to containers using network namespacing.</para>
  41
  42     <para>The module also resolves user and group IDs used by containers to user and group names indicating the
  43     container name, and back. This functionality only applies to containers using user namespacing.</para>
  44
  45     <para>To activate the NSS module, add <literal>mymachines</literal> to the lines starting with
  46     <literal>hosts:</literal>, <literal>passwd:</literal> and <literal>group:</literal> in
  47     <filename>/etc/nsswitch.conf</filename>.</para>
  48
  49     <para>It is recommended to place <literal>mymachines</literal> after the <literal>files</literal> or
  50     <literal>compat</literal> entry of the <filename>/etc/nsswitch.conf</filename> lines to make sure that its mappings
  51     are preferred over other resolvers such as DNS, but so that <filename>/etc/hosts</filename>,
  52     <filename>/etc/passwd</filename> and <filename>/etc/group</filename> based mappings take precedence.</para>
  53   </refsect1>
  54
  55   <refsect1>
  56     <title>Example</title>
  57
  58     <para>Here is an example <filename>/etc/nsswitch.conf</filename> file that enables
  59     <command>nss-mymachines</command> correctly:</para>
  60
  61     <!-- synchronize with other nss-* man pages and factory/etc/nsswitch.conf -->
  62     <programlisting>passwd:         compat <command>mymachines</command> systemd
  63 group:          compat <command>mymachines</command> systemd
  64 shadow:         compat
  65
  66 hosts:          files <command>mymachines</command> resolve [!UNAVAIL=return] dns myhostname
  67 networks:       files
  68
  69 protocols:      db files
  70 services:       db files
  71 ethers:         db files
  72 rpc:            db files
  73
  74 netgroup:       nis</programlisting>
  75
  76   </refsect1>
  77
  78   <refsect1>
  79     <title>See Also</title>
  80     <para>
  81       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  82       <citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
  83       <citerefentry><refentrytitle>nss-systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
  84       <citerefentry><refentrytitle>nss-resolve</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
  85       <citerefentry><refentrytitle>nss-myhostname</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
  86       <citerefentry project='man-pages'><refentrytitle>nsswitch.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  87       <citerefentry project='man-pages'><refentrytitle>getent</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  88     </para>
  89   </refsect1>
  90
  91 </refentry>