mirror of
https://github.com/systemd/systemd-stable.git
synced 2024-12-25 23:21:33 +03:00
f2a20e9966
The text in the man page provides the justification why I think this is generally the right thing. An additional reason is that with the previous commit (to move resolved earlier), since resolved internally implements the same rules that nss-myhostname does, we'd have this strange inversion where the priority of external configuration would be different in the "resolve" path and in the fallback path.
161 lines
7.6 KiB
XML
161 lines
7.6 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
|
|
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//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: <command>mymachines</command> resolve [!UNAVAIL=return] myhostname files dns
|
|
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:/:/usr/sbin/nologin
|
|
vu-rawhide-81:*:20119633:65534:vu-rawhide-81:/:/usr/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: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
|
|
...
|
|
2: host0@if21: <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>
|