machine-id.xml revision 811ad2b3a4f0a53c22ac26a19d1b3e93afcbd32f
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d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering This file is part of systemd.
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering Copyright 2010 Lennart Poettering
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering systemd is free software; you can redistribute it and/or modify it
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering under the terms of the GNU General Public License as published by
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering the Free Software Foundation; either version 2 of the License, or
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering (at your option) any later version.
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering systemd is distributed in the hope that it will be useful, but
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering WITHOUT ANY WARRANTY; without even the implied warranty of
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering General Public License for more details.
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering You should have received a copy of the GNU General Public License
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering along with systemd; If not, see <http://www.gnu.org/licenses/>.
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering <refentryinfo>
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering </authorgroup>
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering </refentryinfo>
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering <refentrytitle>machine-id</refentrytitle>
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering <refpurpose>local machine ID configuration file</refpurpose>
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering <refsynopsisdiv>
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering <para><filename>/etc/machine-id</filename></para>
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering </refsynopsisdiv>
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering <para>The <filename>/etc/machine-id</filename> file
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering configures the unique machine id of the local system
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering that is set during installation. It should contain a
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering single newline-terminated, hexadecimal, lowercase 16
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering character machine ID string.</para>
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering <para>The machine ID is usually generated from a
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering random source during system installation and stays
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering constant for all subsequent boots. Optionally, for
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering stateless systems it is generated during runtime at
811ad2b3a4f0a53c22ac26a19d1b3e93afcbd32fLennart Poettering boot if it is found to be empty.</para>
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering <para>The machine ID does not change based on user
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering configuration, or when hardware is replaced.</para>
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering <para>This machine id follows the same format and
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering logic as the D-Bus machine ID.</para>
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering <para>Programs may use this ID to identify the host
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering with a globally unique ID in the network, that does
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering not change even if the local network configuration
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering changes. Due to this and its greater length it is
7640a5de1b3ffe6547200ad204d14e4f067caf4fLennart Poettering a more useful replacement for the
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering <citerefentry><refentrytitle>gethostid</refentrytitle><manvolnum>3</manvolnum></citerefentry>
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering call POSIX specifies.</para>
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering <para>The simple configuration file format of
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering <filename>/etc/machine-id</filename> originates in the
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering <filename>/var/lib/dbus/machine-id</filename> file
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering introduced by D-Bus. In fact this latter file might be a
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering symlink to the
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering <varname>/etc/machine-id</varname>.</para>
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
d7ccca2e3f86feb81a48e243d8bad78814659a74Lennart Poettering <citerefentry><refentrytitle>gethostid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
7640a5de1b3ffe6547200ad204d14e4f067caf4fLennart Poettering <citerefentry><refentrytitle>hostname</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
7640a5de1b3ffe6547200ad204d14e4f067caf4fLennart Poettering <citerefentry><refentrytitle>machine-info</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
7640a5de1b3ffe6547200ad204d14e4f067caf4fLennart Poettering <citerefentry><refentrytitle>os-release</refentrytitle><manvolnum>5</manvolnum></citerefentry>