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diff --git a/man/nss-mymachines.xml b/man/nss-mymachines.xml new file mode 100644 index 0000000..5742d89 --- /dev/null +++ b/man/nss-mymachines.xml @@ -0,0 +1,163 @@ +<?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: <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> |