man/nss-systemd.xml

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  23
  24 <refentry id="nss-systemd">
  25
  26   <refentryinfo>
  27     <title>nss-systemd</title>
  28     <productname>systemd</productname>
  29
  30     <authorgroup>
  31       <author>
  32         <contrib>Developer</contrib>
  33         <firstname>Lennart</firstname>
  34         <surname>Poettering</surname>
  35         <email>lennart@poettering.net</email>
  36       </author>
  37     </authorgroup>
  38   </refentryinfo>
  39
  40   <refmeta>
  41     <refentrytitle>nss-systemd</refentrytitle>
  42     <manvolnum>8</manvolnum>
  43   </refmeta>
  44
  45   <refnamediv>
  46     <refname>nss-systemd</refname>
  47     <refname>libnss_systemd.so.2</refname>
  48     <refpurpose>Provide UNIX user and group name resolution for dynamic users and groups.</refpurpose>
  49   </refnamediv>
  50
  51   <refsynopsisdiv>
  52     <para><filename>libnss_systemd.so.2</filename></para>
  53   </refsynopsisdiv>
  54
  55   <refsect1>
  56     <title>Description</title>
  57
  58     <para><command>nss-systemd</command> is a plug-in module for the GNU Name Service Switch (NSS) functionality of the
  59     GNU C Library (<command>glibc</command>), providing UNIX user and group name resolution for dynamic users and
  60     groups allocated through the <varname>DynamicUser=</varname> option in systemd unit files. See
  61     <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details on
  62     this option.</para>
  63
  64     <para>This module also ensures that the root and nobody users and groups (i.e. the users/groups with the UIDs/GIDs
  65     0 and 65534) remain resolvable at all times, even if they aren't listed in <filename>/etc/passwd</filename> or
  66     <filename>/etc/group</filename>, or if these files are missing.</para>
  67
  68     <para>To activate the NSS module, add <literal>systemd</literal> to the lines starting with
  69     <literal>passwd:</literal> and <literal>group:</literal> in <filename>/etc/nsswitch.conf</filename>.</para>
  70
  71     <para>It is recommended to place <literal>systemd</literal> after the <literal>files</literal> or
  72     <literal>compat</literal> entry of the <filename>/etc/nsswitch.conf</filename> lines so that
  73     <filename>/etc/passwd</filename> and <filename>/etc/group</filename> based mappings take precedence.</para>
  74   </refsect1>
  75
  76   <refsect1>
  77     <title>Example</title>
  78
  79     <para>Here is an example <filename>/etc/nsswitch.conf</filename> file that enables
  80     <command>nss-systemd</command> correctly:</para>
  81
  82     <programlisting>passwd:         compat mymachines <command>systemd</command>
  83 group:          compat mymachines <command>systemd</command>
  84 shadow:         compat
  85
  86 hosts:          files mymachines resolve myhostname
  87 networks:       files
  88
  89 protocols:      db files
  90 services:       db files
  91 ethers:         db files
  92 rpc:            db files
  93
  94 netgroup:       nis</programlisting>
  95
  96   </refsect1>
  97
  98   <refsect1>
  99     <title>See Also</title>
 100     <para>
 101       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 102       <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 103       <citerefentry><refentrytitle>nss-resolve</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 104       <citerefentry><refentrytitle>nss-myhostname</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 105       <citerefentry><refentrytitle>nss-mymachines</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 106       <citerefentry project='man-pages'><refentrytitle>nsswitch.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 107       <citerefentry project='man-pages'><refentrytitle>getent</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 108     </para>
 109   </refsect1>
 110
 111 </refentry>