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1<?xml version='1.0'?> <!--*-nxml-*-->
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<!--
572eb058 6 SPDX-License-Identifier: LGPL-2.1+
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7-->
8
e7e11bbf 9<refentry id="nss-systemd" conditional='ENABLE_NSS_SYSTEMD'>
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10
11 <refentryinfo>
12 <title>nss-systemd</title>
13 <productname>systemd</productname>
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14 </refentryinfo>
15
16 <refmeta>
17 <refentrytitle>nss-systemd</refentrytitle>
18 <manvolnum>8</manvolnum>
19 </refmeta>
20
21 <refnamediv>
22 <refname>nss-systemd</refname>
23 <refname>libnss_systemd.so.2</refname>
24 <refpurpose>Provide UNIX user and group name resolution for dynamic users and groups.</refpurpose>
25 </refnamediv>
26
27 <refsynopsisdiv>
28 <para><filename>libnss_systemd.so.2</filename></para>
29 </refsynopsisdiv>
30
31 <refsect1>
32 <title>Description</title>
33
34 <para><command>nss-systemd</command> is a plug-in module for the GNU Name Service Switch (NSS) functionality of the
35 GNU C Library (<command>glibc</command>), providing UNIX user and group name resolution for dynamic users and
36 groups allocated through the <varname>DynamicUser=</varname> option in systemd unit files. See
37 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details on
38 this option.</para>
39
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40 <para>This module also ensures that the root and nobody users and groups (i.e. the users/groups with the UIDs/GIDs
41 0 and 65534) remain resolvable at all times, even if they aren't listed in <filename>/etc/passwd</filename> or
42 <filename>/etc/group</filename>, or if these files are missing.</para>
43
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44 <para>To activate the NSS module, add <literal>systemd</literal> to the lines starting with
45 <literal>passwd:</literal> and <literal>group:</literal> in <filename>/etc/nsswitch.conf</filename>.</para>
46
47 <para>It is recommended to place <literal>systemd</literal> after the <literal>files</literal> or
48 <literal>compat</literal> entry of the <filename>/etc/nsswitch.conf</filename> lines so that
49 <filename>/etc/passwd</filename> and <filename>/etc/group</filename> based mappings take precedence.</para>
50 </refsect1>
51
52 <refsect1>
53 <title>Example</title>
54
55 <para>Here is an example <filename>/etc/nsswitch.conf</filename> file that enables
56 <command>nss-systemd</command> correctly:</para>
57
58 <programlisting>passwd: compat mymachines <command>systemd</command>
59group: compat mymachines <command>systemd</command>
60shadow: compat
61
75555c28 62hosts: files mymachines resolve [!UNAVAIL=return] dns myhostname
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63networks: files
64
65protocols: db files
66services: db files
67ethers: db files
68rpc: db files
69
70netgroup: nis</programlisting>
71
72 </refsect1>
73
74 <refsect1>
75 <title>See Also</title>
76 <para>
77 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
78 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
79 <citerefentry><refentrytitle>nss-resolve</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
80 <citerefentry><refentrytitle>nss-myhostname</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
81 <citerefentry><refentrytitle>nss-mymachines</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
82 <citerefentry project='man-pages'><refentrytitle>nsswitch.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
83 <citerefentry project='man-pages'><refentrytitle>getent</refentrytitle><manvolnum>1</manvolnum></citerefentry>
84 </para>
85 </refsect1>
86
87</refentry>