X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=man%2Fmachine-id.xml;h=725370d32dc4e523af18aad4c770754181bec20c;hp=6ca9990988af48df3921448880fa0e9247ff3871;hb=9b15b7846d4de01bb5d9700a24077787e984e8ab;hpb=8d41a963d66e54807e8b0fa69700107e39cf485a diff --git a/man/machine-id.xml b/man/machine-id.xml index 6ca999098..725370d32 100644 --- a/man/machine-id.xml +++ b/man/machine-id.xml @@ -9,22 +9,22 @@ Copyright 2010 Lennart Poettering systemd is free software; you can redistribute it and/or modify it - under the terms of the GNU General Public License as published by - the Free Software Foundation; either version 2 of the License, or + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. systemd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - General Public License for more details. + Lesser General Public License for more details. - You should have received a copy of the GNU General Public License + You should have received a copy of the GNU Lesser General Public License along with systemd; If not, see . --> - /etc/machine-id + machine-id systemd @@ -44,7 +44,7 @@ machine-id - local machine ID configuration file + Local machine ID configuration file @@ -55,32 +55,40 @@ Description The /etc/machine-id file - contains the unique machine id of the local system + contains the unique machine ID of the local system that is set during installation. The machine ID is a - single newline-terminated, hexadecimal, lowercase 32 - character machine ID string. (When decoded from - hexadecimal this corresponds with a 16 byte/128 bit - string.) + single newline-terminated, hexadecimal, 32-character, + lowercase machine ID string. When decoded from + hexadecimal, this corresponds with a 16-byte/128-bit + string. The machine ID is usually generated from a random source during system installation and stays constant for all subsequent boots. Optionally, for - stateless systems it is generated during runtime at + stateless systems, it is generated during runtime at boot if it is found to be empty. The machine ID does not change based on user - configuration, or when hardware is replaced. + configuration or when hardware is replaced. This machine ID adheres to the same format and logic as the D-Bus machine ID. Programs may use this ID to identify the host - with a globally unique ID in the network, that does + with a globally unique ID in the network, which does not change even if the local network configuration - changes. Due to this and its greater length it is + changes. Due to this and its greater length, it is a more useful replacement for the gethostid3 - call POSIX specifies. + call that POSIX specifies. + + The + systemd-machine-id-setup1 + tool may be used by installer tools to initialize the + machine ID at install time. Use + systemd-firstboot1 + to initialize it on mounted (but not booted) system + images. @@ -88,9 +96,9 @@ Note that the machine ID historically is not an OSF UUID as defined by RFC - 4122, nor a Microsoft GUID. Starting with - systemd v30 newly generated machine IDs however do + url="https://tools.ietf.org/html/rfc4122">RFC + 4122, nor a Microsoft GUID; however, starting with + systemd v30, newly generated machine IDs do qualify as v4 UUIDs. In order to maintain compatibility with existing @@ -108,7 +116,7 @@ id[8] = (id[8] & 0x3F) | 0x80; (This code is inspired by generate_random_uuid() of drivers/char/random.c from the - kernel sources.) + Linux kernel sources.) @@ -118,7 +126,7 @@ id[8] = (id[8] & 0x3F) | 0x80; The simple configuration file format of /etc/machine-id originates in the /var/lib/dbus/machine-id file - introduced by D-Bus. In fact this latter file might be a + introduced by D-Bus. In fact, this latter file might be a symlink to /etc/machine-id. @@ -127,10 +135,14 @@ id[8] = (id[8] & 0x3F) | 0x80; See Also systemd1, + systemd-machine-id-setup1, gethostid3, hostname5, machine-info5, - os-release5 + os-release5, + sd-id1283, + sd_id128_get_machine3, + systemd-firstboot1