man/nss-systemd.xml

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  10   Copyright 2016 Lennart Poettering
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  25
  26 <refentry id="nss-systemd" conditional='ENABLE_NSS_SYSTEMD'>
  27
  28   <refentryinfo>
  29     <title>nss-systemd</title>
  30     <productname>systemd</productname>
  31
  32     <authorgroup>
  33       <author>
  34         <contrib>Developer</contrib>
  35         <firstname>Lennart</firstname>
  36         <surname>Poettering</surname>
  37         <email>lennart@poettering.net</email>
  38       </author>
  39     </authorgroup>
  40   </refentryinfo>
  41
  42   <refmeta>
  43     <refentrytitle>nss-systemd</refentrytitle>
  44     <manvolnum>8</manvolnum>
  45   </refmeta>
  46
  47   <refnamediv>
  48     <refname>nss-systemd</refname>
  49     <refname>libnss_systemd.so.2</refname>
  50     <refpurpose>Provide UNIX user and group name resolution for dynamic users and groups.</refpurpose>
  51   </refnamediv>
  52
  53   <refsynopsisdiv>
  54     <para><filename>libnss_systemd.so.2</filename></para>
  55   </refsynopsisdiv>
  56
  57   <refsect1>
  58     <title>Description</title>
  59
  60     <para><command>nss-systemd</command> is a plug-in module for the GNU Name Service Switch (NSS) functionality of the
  61     GNU C Library (<command>glibc</command>), providing UNIX user and group name resolution for dynamic users and
  62     groups allocated through the <varname>DynamicUser=</varname> option in systemd unit files. See
  63     <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details on
  64     this option.</para>
  65
  66     <para>This module also ensures that the root and nobody users and groups (i.e. the users/groups with the UIDs/GIDs
  67     0 and 65534) remain resolvable at all times, even if they aren't listed in <filename>/etc/passwd</filename> or
  68     <filename>/etc/group</filename>, or if these files are missing.</para>
  69
  70     <para>To activate the NSS module, add <literal>systemd</literal> to the lines starting with
  71     <literal>passwd:</literal> and <literal>group:</literal> in <filename>/etc/nsswitch.conf</filename>.</para>
  72
  73     <para>It is recommended to place <literal>systemd</literal> after the <literal>files</literal> or
  74     <literal>compat</literal> entry of the <filename>/etc/nsswitch.conf</filename> lines so that
  75     <filename>/etc/passwd</filename> and <filename>/etc/group</filename> based mappings take precedence.</para>
  76   </refsect1>
  77
  78   <refsect1>
  79     <title>Example</title>
  80
  81     <para>Here is an example <filename>/etc/nsswitch.conf</filename> file that enables
  82     <command>nss-systemd</command> correctly:</para>
  83
  84     <programlisting>passwd:         compat mymachines <command>systemd</command>
  85 group:          compat mymachines <command>systemd</command>
  86 shadow:         compat
  87
  88 hosts:          files mymachines resolve [!UNAVAIL=return] dns myhostname
  89 networks:       files
  90
  91 protocols:      db files
  92 services:       db files
  93 ethers:         db files
  94 rpc:            db files
  95
  96 netgroup:       nis</programlisting>
  97
  98   </refsect1>
  99
 100   <refsect1>
 101     <title>See Also</title>
 102     <para>
 103       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 104       <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 105       <citerefentry><refentrytitle>nss-resolve</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 106       <citerefentry><refentrytitle>nss-myhostname</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 107       <citerefentry><refentrytitle>nss-mymachines</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 108       <citerefentry project='man-pages'><refentrytitle>nsswitch.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 109       <citerefentry project='man-pages'><refentrytitle>getent</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 110     </para>
 111   </refsect1>
 112
 113 </refentry>