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">
6 SPDX-License-Identifier: LGPL-2.1+
8 This file is part of systemd.
10 Copyright 2016 Lennart Poettering
12 systemd is free software; you can redistribute it and/or modify it
13 under the terms of the GNU Lesser General Public License as published by
14 the Free Software Foundation; either version 2.1 of the License, or
15 (at your option) any later version.
17 systemd is distributed in the hope that it will be useful, but
18 WITHOUT ANY WARRANTY; without even the implied warranty of
19 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 Lesser General Public License for more details.
22 You should have received a copy of the GNU Lesser General Public License
23 along with systemd; If not, see <http://www.gnu.org/licenses/>.
26 <refentry id=
"nss-systemd" conditional='ENABLE_NSS_SYSTEMD'
>
29 <title>nss-systemd
</title>
30 <productname>systemd
</productname>
34 <contrib>Developer
</contrib>
35 <firstname>Lennart
</firstname>
36 <surname>Poettering
</surname>
37 <email>lennart@poettering.net
</email>
43 <refentrytitle>nss-systemd
</refentrytitle>
44 <manvolnum>8</manvolnum>
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>
54 <para><filename>libnss_systemd.so
.2</filename></para>
58 <title>Description
</title>
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
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>
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>
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>
79 <title>Example
</title>
81 <para>Here is an example
<filename>/etc/nsswitch.conf
</filename> file that enables
82 <command>nss-systemd
</command> correctly:
</para>
84 <programlisting>passwd: compat mymachines
<command>systemd
</command>
85 group: compat mymachines
<command>systemd
</command>
88 hosts: files mymachines resolve [!UNAVAIL=return] dns myhostname
96 netgroup: nis
</programlisting>
101 <title>See Also
</title>
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>