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Merge pull request #10989 from keszybz/nss-man

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Add example to nss-mymachines(8)
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Lennart Poettering 2018-11-29 19:28:39 +01:00 committed by GitHub
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82
man/nss-mymachines.xml
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@ -35,12 +35,21 @@
<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
<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.</para>
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 resolves user and group IDs used by containers to user and group names indicating the
container name, and back. This functionality only applies to containers using user namespacing.</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
@ -53,7 +62,7 @@
</refsect1>
<refsect1>
<title>Example</title>
<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>
@ -75,11 +84,74 @@ 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>,

26
src/machine/machinectl.c
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@ -332,7 +332,7 @@ static int list_machines(int argc, char *argv[], void *userdata) {
name,
0,
"",
"",
" ",
arg_addrs,
&addresses);
@ -475,20 +475,6 @@ static int show_unit_cgroup(sd_bus *bus, const char *unit, pid_t leader) {
return 0;
}
static int print_addresses(sd_bus *bus, const char *name, int ifi, const char *prefix, const char *prefix2, int n_addr) {
_cleanup_free_ char *s = NULL;
int r;
r = call_get_addresses(bus, name, ifi, prefix, prefix2, n_addr, &s);
if (r < 0)
return r;
if (r > 0)
fputs(s, stdout);
return r;
}
static int print_os_release(sd_bus *bus, const char *method, const char *name, const char *prefix) {
_cleanup_free_ char *pretty = NULL;
int r;
@ -561,6 +547,7 @@ static void machine_status_info_clear(MachineStatusInfo *info) {
static void print_machine_status_info(sd_bus *bus, MachineStatusInfo *i) {
char since1[FORMAT_TIMESTAMP_RELATIVE_MAX];
char since2[FORMAT_TIMESTAMP_MAX];
_cleanup_free_ char *addresses = NULL;
const char *s1, *s2;
int ifi = -1;
@ -630,11 +617,12 @@ static void print_machine_status_info(sd_bus *bus, MachineStatusInfo *i) {
fputc('\n', stdout);
}
if (print_addresses(bus, i->name, ifi,
"\t Address: ",
"\n\t ",
ALL_IP_ADDRESSES) > 0)
if (call_get_addresses(bus, i->name, ifi,
"\t Address: ", "\n\t ", ALL_IP_ADDRESSES,
&addresses) > 0) {
fputs(addresses, stdout);
fputc('\n', stdout);
}
print_os_release(bus, "GetMachineOSRelease", i->name, "\t OS: ");