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+<?xml version='1.0'?> <!--*-nxml-*-->
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+ "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+
+<!--
+ SPDX-License-Identifier: LGPL-2.1+
+-->
+
+<refentry id="nss-mymachines" conditional='ENABLE_NSS_MYMACHINES'>
+
+ <refentryinfo>
+ <title>nss-mymachines</title>
+ <productname>systemd</productname>
+ </refentryinfo>
+
+ <refmeta>
+ <refentrytitle>nss-mymachines</refentrytitle>
+ <manvolnum>8</manvolnum>
+ </refmeta>
+
+ <refnamediv>
+ <refname>nss-mymachines</refname>
+ <refname>libnss_mymachines.so.2</refname>
+ <refpurpose>Provide hostname resolution for local
+ container instances.</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <para><filename>libnss_mymachines.so.2</filename></para>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para><command>nss-mymachines</command> is a plug-in module for the GNU Name Service Switch (NSS) functionality of
+ the GNU C Library (<command>glibc</command>), providing hostname resolution for the names of containers running
+ locally that are registered with
+ <citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>. The
+ container names are resolved to the IP addresses of the specific container, ordered by their scope. This
+ functionality only applies to containers using network namespacing (see the description of
+ <option>--private-network</option> in
+ <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>).
+ Note that the name that is resolved is the one registered with <command>systemd-machined</command>, which
+ may be different than the hostname configured inside of the container.</para>
+
+ <para>The module also provides name resolution for user and group identifiers mapped to containers. All names from
+ the range allocated to a given container <replaceable>container</replaceable> are exposed on the host as
+ <literal>vu-<replaceable>container</replaceable>-<replaceable>uid</replaceable></literal> and
+ <literal>vg-<replaceable>container</replaceable>-<replaceable>gid</replaceable></literal> (see example below). This
+ functionality only applies to containers using user namespacing (see the description of
+ <option>--private-users</option> in
+ <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>).</para>
+
+ <para>To activate the NSS module, add <literal>mymachines</literal> to the lines starting with
+ <literal>hosts:</literal>, <literal>passwd:</literal> and <literal>group:</literal> in
+ <filename>/etc/nsswitch.conf</filename>.</para>
+
+ <para>It is recommended to place <literal>mymachines</literal> after the <literal>files</literal> or
+ <literal>compat</literal> entry of the <filename>/etc/nsswitch.conf</filename> lines to make sure that its mappings
+ are preferred over other resolvers such as DNS, but so that <filename>/etc/hosts</filename>,
+ <filename>/etc/passwd</filename> and <filename>/etc/group</filename> based mappings take precedence.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Configuration in <filename>/etc/nsswitch.conf</filename></title>
+
+ <para>Here is an example <filename>/etc/nsswitch.conf</filename> file that enables
+ <command>nss-mymachines</command> correctly:</para>
+
+ <!-- synchronize with other nss-* man pages and factory/etc/nsswitch.conf -->
+ <programlisting>passwd: compat <command>mymachines</command> systemd
+group: compat <command>mymachines</command> systemd
+shadow: compat
+
+hosts: files <command>mymachines</command> resolve [!UNAVAIL=return] dns myhostname
+networks: files
+
+protocols: db files
+services: db files
+ethers: db files
+rpc: db files
+
+netgroup: nis</programlisting>
+
+ </refsect1>
+
+ <refsect1>
+ <title>Mappings provided by <filename>nss-mymachines</filename></title>
+
+ <para>The container <literal>rawhide</literal> is spawned using
+ <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>:
+ </para>
+
+ <programlisting># systemd-nspawn -M rawhide --boot --network-veth --private-users=pick
+Spawning container rawhide on /var/lib/machines/rawhide.
+Selected user namespace base 20119552 and range 65536.
+...
+
+$ machinectl --max-addresses=3
+MACHINE CLASS SERVICE OS VERSION ADDRESSES
+rawhide container systemd-nspawn fedora 30 169.254.40.164 fe80::94aa:3aff:fe7b:d4b9
+
+$ getent passwd vu-rawhide-0 vu-rawhide-81
+vu-rawhide-0:*:20119552:65534:vu-rawhide-0:/:/sbin/nologin
+vu-rawhide-81:*:20119633:65534:vu-rawhide-81:/:/sbin/nologin
+
+$ getent group vg-rawhide-0 vg-rawhide-81
+vg-rawhide-0:*:20119552:
+vg-rawhide-81:*:20119633:
+
+$ ps -o user:15,pid,tty,command -e|grep '^vu-rawhide'
+vu-rawhide-0 692 ? /usr/lib/systemd/systemd
+vu-rawhide-0 731 ? /usr/lib/systemd/systemd-journald
+vu-rawhide-192 734 ? /usr/lib/systemd/systemd-networkd
+vu-rawhide-193 738 ? /usr/lib/systemd/systemd-resolved
+vu-rawhide-0 742 ? /usr/lib/systemd/systemd-logind
+vu-rawhide-81 744 ? /usr/bin/dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-activation --syslog-only
+vu-rawhide-0 746 ? /usr/sbin/sshd -D ...
+vu-rawhide-0 752 ? /usr/lib/systemd/systemd --user
+vu-rawhide-0 753 ? (sd-pam)
+vu-rawhide-0 1628 ? login -- zbyszek
+vu-rawhide-1000 1630 ? /usr/lib/systemd/systemd --user
+vu-rawhide-1000 1631 ? (sd-pam)
+vu-rawhide-1000 1637 pts/8 -zsh
+
+$ ping -c1 rawhide
+PING rawhide(fe80::94aa:3aff:fe7b:d4b9%ve-rawhide (fe80::94aa:3aff:fe7b:d4b9%ve-rawhide)) 56 data bytes
+64 bytes from fe80::94aa:3aff:fe7b:d4b9%ve-rawhide (fe80::94aa:3aff:fe7b:d4b9%ve-rawhide): icmp_seq=1 ttl=64 time=0.045 ms
+...
+$ ping -c1 -4 rawhide
+PING rawhide (169.254.40.164) 56(84) bytes of data.
+64 bytes from 169.254.40.164 (169.254.40.164): icmp_seq=1 ttl=64 time=0.064 ms
+...
+
+# machinectl shell rawhide /sbin/ip a
+Connected to machine rawhide. Press ^] three times within 1s to exit session.
+1: lo: &lt;LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
+ ...
+2: host0@if21: &lt;BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
+ link/ether 96:aa:3a:7b:d4:b9 brd ff:ff:ff:ff:ff:ff link-netnsid 0
+ inet 169.254.40.164/16 brd 169.254.255.255 scope link host0
+ valid_lft forever preferred_lft forever
+ inet6 fe80::94aa:3aff:fe7b:d4b9/64 scope link
+ valid_lft forever preferred_lft forever
+Connection to machine rawhide terminated.
+</programlisting>
+ </refsect1>
+
+ <refsect1>
+ <title>See Also</title>
+ <para>
+ <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>nss-systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>nss-resolve</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>nss-myhostname</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ <citerefentry project='man-pages'><refentrytitle>nsswitch.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry project='man-pages'><refentrytitle>getent</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ </para>
+ </refsect1>
+
+</refentry>