Deploying SUSE Linux Micro Using an ISO Image
- WHAT?
SUSE Linux Micro provides selfinstall images (also referred to as pre-built images) that can be deployed directly to your device storage: a memory card, a USB flash disk or a hard disk. The type of device you can deploy the image to is determined by your specific hardware. Refer to your vendor's documentation for guidance.
- WHY?
You need to know how to deploy SUSE Linux Micro on your system.
- EFFORT
It takes approximately 20 minutes to read the article.
- GOAL
SUSE Linux Micro is successfully deployed on your system.
- REQUIREMENTS
Understanding for which environment the selfinstall disk image is suited. For details, refer to the Introduction to SUSE Linux Micro article.
A device with at least 20 GB disk space, where you deploy the raw image and where SUSE Linux Micro will run
Optionally, a configuration medium, for example, a USB flash disk.
1 About pre-built images #
Pre-built images are ready-to-use representations of a running operating system. They are not installed in a traditional way using an installer, but copied to the hard disk of the target host. The topic covers basic information about these pre-built images.
The pre-built images are intended to be configured on the first boot by using tools delivered in the images. The boot loader detects the first boot as described in Section 1.1, “First boot detection”.
1.1 First boot detection #
The deployment configuration runs on the first boot only. To distinguish
between the first and subsequent boots, the file
/etc/machine-id is created after the
first boot finishes. If the file is not present in the file system, the system assumes that
this is a first boot and triggers the configuration process. After completing the first boot, the
/etc/machine-id file is
created.
/etc/machine-id file is always created
Even though the configuration may not be successful because of improper
or missing configuration files, the
/etc/machine-id file is
created.
1.1.1 Force system reconfiguration on a subsequent boot #
If you need to reconfigure your system after the first boot happened, you can force the reconfiguration on the subsequent boot. Here you have two options.
You can pass the
ignition.firstbootorcombustion.firstbootattribute to the kernel command line.You can delete the file
/etc/machine-idand reboot the system.
2 Preparing the configuration device #
During the installation process, you can pass a complex configuration to define users, directories, or to provide SSH keys. To do so, create a configuration device that is later processed by either Ignition or Combustion.
By default, root SSH login in SUSE Linux Micro is permitted only by using the SSH
key. We recommend creating an unprivileged user during the deployment process that you can
use to access the installed system. You can create an unprivileged user account on the first
boot by using either the Combustion or Ignition tool. Creating an unprivileged user
during system deployment is useful for accessing the Cockpit Web interface as well.
To prepare the configuration device, proceed as follows:
Format the disk to any file system supported by SUSE Linux Micro: Ext3, Ext4, etc.:
>sudo mkfs.ext4 /dev/sdYSet the device label to either
ignition(when either Ignition or Combustion is used) orcombustion(when only Combustion is used). If needed (for example, on Windows host), use uppercase letters for the labels. To label the device, run:>sudo e2label /dev/sdY ignitionYou can use any type of configuration storage media that your virtualization system or your hardware supports: an ISO image, a USB flash disk, etc.
Mount the device:
>sudo mount /dev/sdY /mntCreate the directory structure as mentioned in Section 2.1.1.1, “
config.ign” or Section 2.2, “Configuring SUSE Linux Micro deployment with Combustion”, depending on the configuration tool used:>sudo mkdir /mnt/ignition/or:
>sudo mkdir -p /mnt/combustion/Prepare all elements of the configuration that will be used by Ignition or Combustion.
2.1.1 How does Ignition work? #
When the system is booted for the first time, Ignition is loaded as
part of an initramfs and searches for a
configuration file within a specific directory (on a USB flash disk, or
you can provide a URL). All changes are performed before the kernel
switches from the temporary file system to the real root file system
(before the switch_root command is issued).
Ignition uses a configuration file in the JSON format named
config.ign. You can either write the configuration
manually or use the Fuel Ignition Web application at
https://ignite.opensuse.org to generate it.
Fuel Ignition does not cover the complete Ignition vocabulary yet, and the resulting JSON file may need additional manual tweaking.
2.1.1.1 config.ign #
The config.ign contains multiple data types:
objects, strings, integers, booleans and lists of objects. For a
complete specification, refer to
Ignition
specification v3.3.0.
The version attribute is mandatory and in case of
SUSE Linux Micro, its value must be set either to
3.4.0 or to any lower version. Otherwise, Ignition
will fail.
To log in to your system as root, you must at least
include a password for root. However, it is recommended to
establish access via SSH keys. To configure a password, make sure to
use a secure one. If you use a randomly generated password, use at
least 10 characters. If you create your password manually, use even
more than 10 characters and combine uppercase and lowercase letters and
numbers.
2.1.2 Ignition configuration examples #
This section provides several examples of the Ignition configuration in the built-in JSON format.
version attribute is mandatory
Each config.ign must include version 3.4.0 or
lower that is then converted to the corresponding Ignition
specification.
2.1.2.1 Default partitioning #
Each image has the following subvolumes:
/home /root /opt /srv /usr/local /var
The /etc directory is mounted as overlayFS, where the
upper directory is mounted to /var/lib/overlay/1/etc/.
You can recognize the subvolumes mounted by default by the option
x-initrd.mount in /etc/fstab. Other
subvolumes or partitions must be configured either by Ignition or
Combustion.
If you want to add a new user or modify any of the files on a subvolume that is not mounted by default, you need to declare such subvolume first so that it is mounted as well.
2.1.2.2 Storage configuration #
The storage attribute is used to configure
partitions, RAID, define file systems, create files, etc. To define
partitions, use the disks attribute. The
filesystems attribute is used to format partitions. The
files attribute can be used to create files in the
file system.
The example below configures four partitions, including a dedicated swap partition, and creates a file system on each partition.
{
"ignition": {
"version": "3.0.0"
},
"storage": {
"disks": [
{
"device": "/dev/vda",
"partitions": [
{
"label": "root",
"number": 1,
"sizeMiB": 30720
},
{
"label": "boot",
"number": 2,
"sizeMiB": 8720
},
{
"label": "swap",
"number": 3,
"sizeMiB": 4096
},
{
"label": "home",
"number": 4,
"sizeMiB": 30720
}
],
"wipeTable": true
}
]
"filesystems": [
{
"device": "/dev/disk/by-partlabel/root",
"format": "btrfs",
"label": "root"
},
{
"device": "/dev/disk/by-partlabel/swap",
"format": "swap",
"label": "swap"
}
{
"device": "/dev/disk/by-partlabel/boot",
"format": "btrfs",
"label": "boot"
}
{
"device": "/dev/disk/by-partlabel/home",
"format": "ext4",
"label": "home"
}
]
}
}Each of the mentioned attributes is described in the following sections.
2.1.2.2.1 The disks attribute #
The disks attribute is a list of devices that
enables you to define partitions on these devices. The
disks attribute must contain at least one
device, other attributes are optional. Keep in mind that at least the
root and boot partitions (swap if configured) need to be formatted to bear a file
system.
The following example uses a single virtual device and divides the disk into four partitions:
...
"storage": {
"disks": [
{
"device": "/dev/vda",
"partitions": [
{
"label": "root", 1
"number": 1, 2
"sizeMiB": 30720 3
},
{
"label": "boot",
"number": 2,
"startMiB": 30720, 4
"sizeMiB": 8720
},
{
"label": "swap",
"number": 3,
"sizeMiB": 4096
},
{
"label": "home",
"number": 4,
"sizeMiB": 30720
}
],
"wipeTable": true
}
]
...The partition identification. Depending on the partition file system, it can have up to 16 characters for EXT-type file systems and 256 characters in the case of Btrfs. | |
The position of the partition in the partition table. If set to 0, the next free position is used. | |
The size of the partition in MiB. | |
Identifies the starting point of the particular partition. |
2.1.2.2.2 The raid attribute #
The raid is a list of RAID arrays. The following
attributes of raid are mandatory:
- level
a level of the particular RAID array (linear, raid0, raid1, raid2, raid3, raid4, raid5, raid6)
- devices
a list of devices in the array referenced by their absolute paths
- name
a name that will be used for the md device
For example:
{
"ignition": {
"version": "3.0.0"
},
"storage": {
"raid": [
{
"devices": [
"/dev/sda",
"/dev/sdb"
],
"level": "raid1",
"name": "system"
}
]
}
}2.1.2.2.3 The filesystems attribute #
The filesystems attribute does not modify mount units. If you add a new partition or remove an
existing partition, you must manually adjust the mount units.
When changing partitioning, do not place the following directories on a different partition
than the root file system: /boot, /usr,
/etc, /dev.
filesystems must contain the following attributes:
- device
the absolute path to the device, typically
/dev/sdain case of physical disk- format
the file system format (btrfs, ext4, ext3, xfs, vfat or swap)
NoteIn case of SUSE Linux Micro, the
rootfile system must be formatted to Btrfs.
The following example demonstrates using the
filesystems attribute. The
/opt directory will be mounted to the
/dev/sda1 partition, which is formatted to Btrfs.
The device will not be erased.
For example:
{
"ignition": {
"version": "3.0.0"
},
"storage": {
"filesystems": [
{
"device": "/dev/sda1",
"format": "btrfs",
"path": "/opt",
"wipeFilesystem": false
}
]
}
}
Normally, a regular user's home directory is located in the
/home/USER_NAME
directory. Since /home is not mounted by default
in the initrd, the mount has to be explicitly defined for the user
creation to succeed:
{
"ignition": {
"version": "3.1.0"
},
"passwd": {
"users": [
{
"name": "root",
"passwordHash": "PASSWORD_HASH",
"sshAuthorizedKeys": [
"ssh-rsa SSH_KEY_HASH"
]
}
]
},
"storage": {
"filesystems": [
{
"device": "/dev/sda3",
"format": "btrfs",
"mountOptions": [
"subvol=/@/home"
],
"path": "/home",
"wipeFilesystem": false
}
]
}
}2.1.2.2.4 The files attribute #
You can use the files attribute to create any
files on your machine. Bear in mind that to create files
outside the default partitioning schema, you need to define the
directories by using the filesystems attribute.
In the following example, a host name is created by using the
files attribute. The file
/etc/hostname will be created with the
sl-micro1 host name:
Keep in mind that JSON accepts file modes in decimal numbers, for
example, 420.
JSON:
{
"ignition": {
"version": "3.0.0"
},
"storage": {
"files": [
{
"overwrite": true,
"path": "/etc/hostname",
"contents": {
"source": "data:,sl-micro1"
},
"mode": 420
}
]
}
}2.1.2.2.5 The directories attribute #
The directories attribute is a list of directories
that will be created in the file system. The
directories attribute must contain at least one
path attribute.
For example:
{
"ignition": {
"version": "3.0.0"
},
"storage": {
"directories": [
{
"path": "/home/tux",
"user": {
"name": "tux"
}
}
]
}
}2.1.2.3 Users administration #
The passwd attribute is used to add users. As some services, such as Cockpit, require login using a non-root user, define at
least one unprivileged user here. Alternatively, you can create such a user from a running
system as described in Section 4.2, “Adding users”.
To log in to your system, create root and a regular user and set their
passwords. You need to hash the passwords, for example, by
using the openssl command:
openssl passwd -6
The command creates a hash of the password you chose. Use this hash as
the value of the password_hash attribute.
For example:
{
"ignition": {
"version": "3.0.0"
},
"passwd": {
"users": [
{
"name": "root",
"passwordHash": "PASSWORD_HASH",
"sshAuthorizedKeys": [
"ssh-rsa SSH_KEY_HASH USER@HOST"
]
}
]
}
}
The users attribute must contain at least one
name attribute.
ssh_authorized_keys is a list of ssh keys for the
user.
2.1.2.4 Enabling systemd services #
You can enable systemd services by specifying them in the
systemd attribute.
For example:
{
"ignition": {
"version": "3.0.0"
},
"systemd": {
"units": [
{
"enabled": true,
"name": "sshd.service"
}
]
}
}2.2 Configuring SUSE Linux Micro deployment with Combustion #
Combustion is a dracut module that enables you to configure your system on the first boot. You can use Combustion, for example, to change the default partitions, set user passwords, create files, or install packages.
2.2.1 How does Combustion work? #
Combustion is invoked after the ignition.firstboot
argument is passed to the kernel command line. Combustion reads a
provided file named script, executes included
commands, and thus performs changes to the file system. If
script includes the network flag, Combustion tries
to configure the network. After /sysroot is mounted,
Combustion tries to activate all mount points in
/etc/fstab and then calls
transactional-update to apply other changes, for
example, setting root password or installing packages.
Combustion can be used along with Ignition. If you intend to do
so, label your configuration medium ignition and
include the ignition directory with the
config.ign to your directory structure as shown
below:
<root directory>
└── combustion
└── script
└── other files
└── ignition
└── config.ignIn this scenario, Ignition runs before Combustion.
2.2.2 Combustion configuration examples #
2.2.2.1 The script configuration file #
The script configuration file is a set of commands
that are parsed and executed by Combustion in a transactional-update shell. This
article provides examples of configuration tasks performed by
Combustion.
To create the Combustion script, you can use the Fuel Ignition Web application. There you can select appropriate parameters and the application generates a Combustion script that you can download.
As the script file is interpreted by the shell,
always start the file with the interpreter declaration on its first
line. For example, in case of Bash:
#!/bin/bash
To log in to your system, include at least the root password.
However, it is recommended to establish the authentication using SSH
keys. If you need to use a root password, make sure to configure a
secure password. For a randomly generated password, use at least 10
characters. If you create your password manually, use even more than 10
characters and combine uppercase and lowercase letters and numbers.
2.2.2.1.1 Default partitioning #
Each image has the following subvolumes:
/home /root /opt /srv /usr/local /var
The /etc directory is mounted as overlayFS, where the
upper directory is mounted to /var/lib/overlay/1/etc/.
You can recognize the subvolumes mounted by default by the option
x-initrd.mount in /etc/fstab. Other
subvolumes or partitions must be configured either by Ignition or
Combustion.
If you want to add a new user or modify any of the files on a subvolume that is not mounted by default, you need to declare such subvolume first so that it is mounted as well.
2.2.2.1.2 Network configuration #
To configure and use the network connection during the first boot, add
the following statement to script:
# combustion: network
Using this statement passes the rd.neednet=1
argument to dracut. The network configuration defaults to using DHCP.
If a different network configuration is needed, proceed as described in
Section 2.2.2.1.3, “Performing modifications in the initramfs”.
If you do not use the statement, the system remains configured without any network connection.
2.2.2.1.3 Performing modifications in the initramfs #
You may need to perform changes to the initramfs environment, for
example, to write a custom network configuration for NetworkManager into
/etc/NetworkManager/system-connections/. To do so,
use the prepare statement.
For example, to create a connection with a static IP address and configure DNS:
#!/bin/bash
# combustion: network prepare
set -euxo pipefail
nm_config() {
umask 077 # Required for NM config
mkdir -p /etc/NetworkManager/system-connections/
cat >/etc/NetworkManager/system-connections/static.nmconnection <<-EOF
[connection]
id=static
type=ethernet
autoconnect=true
[ipv4]
method=manual
dns=192.168.100.1
address1=192.168.100.42/24,192.168.100.1
EOF
}
if [ "${1-}" = "--prepare" ]; then
nm_config # Configure NM in the initrd
exit 0
fi
# Redirect output to the console
exec > >(exec tee -a /dev/tty0) 2>&1
nm_config # Configure NM in the system
curl example.com
# Close outputs and wait for tee to finish
exec 1>&- 2>&-; wait;
# Leave a marker
echo "Configured with combustion" > /etc/issue.d/combustion2.2.2.1.4 Waiting for the task to complete #
Some processes may be run in background, for example, the tee process
that redirects output to the terminal. To ensure that all running processes are completed before the
script
execution finishes, add the following line:
exec 1>&- 2>&-; wait;
2.2.2.1.5 Partitioning #
SUSE Linux Micro raw images are delivered with a default partitioning
scheme. You might want to
use a different partitioning. The following set of example snippets
moves the /home to a different partition.
When changing partitioning, do not place the following directories on a different partition
than the root file system: /boot, /usr,
/etc, /dev.
The following script performs changes that are not included in
snapshots. If the script fails and the snapshot is discarded, certain
changes remain visible and cannot be reverted, for example, the
changes to the /dev/vdb device.
The following snippet creates a GPT partitioning schema with a single
partition on the /dev/vdb device:
sfdisk /dev/vdb <<EOF sleep 1 label: gpt type=linux EOF partition=/dev/vdb1
As the sfdisk command may take longer time to complete, postpone
label by using the
sleep command after sfdisk.
The partition is formatted to Btrfs:
wipefs --all ${partition}
mkfs.btrfs ${partition}
Possible content of /home is moved to the new
/home folder location by the following snippet:
mount /home
mount ${partition} /mnt
rsync -aAXP /home/ /mnt/
umount /home /mnt
The snippet below removes an old entry in
/etc/fstab and creates a new entry:
awk -i inplace '$2 != "/home"' /etc/fstab
echo "$(blkid -o export ${partition} | grep ^UUID=) /home btrfs defaults 0 0" >>/etc/fstab2.2.2.1.6 Creating new users #
As some services, such as Cockpit, require login using a non-root user, define at least one unprivileged user here. Alternatively, you can create such a user from a running system as described in Section 4.2, “Adding users”.
To add a new user account, first create a hash string that represents
the user's password. Use the openssl passwd -6
command.
After you obtain the password hash, add the following lines to the
script:
mount /home useradd -m EXAMPLE_USER echo 'EXAMPLE_USER:PASSWORD_HASH' | chpasswd -e
2.2.2.1.7 Setting a password for root #
Before you set the root password, generate a hash of the
password, for example, by using the openssl passwd
-6. To set the password, add the following line to the
script:
echo 'root:PASSWORD_HASH' | chpasswd -e
2.2.2.1.8 Adding SSH keys #
The following snippet creates a directory to store the root's SSH
key and then copies the public SSH key located on the configuration
device to the authorized_keys file.
mkdir -pm700 /root/.ssh/ cat id_rsa_new.pub >> /root/.ssh/authorized_keys
The SSH service must be enabled in case you need to use remote login via SSH. For details, refer to Section 2.2.2.1.9, “Enabling services”.
2.2.2.1.9 Enabling services #
To enable system services, for example, the SSH service, add the
following line to script:
systemctl enable sshd.service
2.2.2.1.10 Installing packages #
As certain packages may require additional subscription, you may need to register your system beforehand. An available network connection may also be needed to install additional packages.
During the first boot configuration, you can install additional
packages to your system. For example, you can install the
vim editor by adding:
zypper --non-interactive install vim-small
Bear in mind that you will not be able to use
zypper after the configuration is complete and you
boot to the configured system. To perform changes later, you must use
the transactional-update command to create a
changed snapshot.
3 Deploying a selfinstall ISO image #
Dracut does not automatically assemble special devices on a disk, such as crypto_LUKS, dmraid, mdraid or LVM, unless they are explicitly configured in the system. These devices may come from
previous use of the disks. To enable auto-assembly, add rd.auto=1 to kernel command-line.
For other command-line parameters controlling the auto-assembly of
individual types of special devices, refer to the dracut documentation.
The following procedure describes how to deploy SUSE Linux Micro using the selfinstall ISO image:
Download the image.
Boot your machine with the selfinstall ISO attached.
Select to start the installation process.
Select the disk where SUSE Linux Micro will be installed and confirm that you want to delete data on the disk. A SUSE Linux Micro image is then copied to the disk.
Using Kexec, your system reboots and is then prepared for the configuration process.
Start the configuration process by selecting . If the configuration device is provided, SUSE Linux Micro is configured according to the instructions provided on the configuration device. Otherwise JeOS Firstboot is triggered as described in Section 3.1, “Configuring SUSE Linux Micro with JeOS Firstboot”.
After the configuration process is complete, you can log in to your system.
Perform post-deployment steps as described in Section 4, “Post-deployment steps”.
To skip the prompt about the target device, you can use a custom image that enables you to pass
this target device using the
rd.kiwi.oem.installdevice option on the kernel command line. For details, refer
to the boot
process customization workflow.
3.1 Configuring SUSE Linux Micro with JeOS Firstboot #
When booting SUSE Linux Micro for the first time without providing any configuration device, JeOS Firstboot enables you to perform a minimal configuration of your system. If you need more control over the deployment process, use a configuration device with either Ignition or Combustion configuration. Find more information in Section 2.1, “Configuring SUSE Linux Micro deployment with Ignition” and Section 2.2, “Configuring SUSE Linux Micro deployment with Combustion”.
To configure the system with JeOS Firstboot, proceed as follows:
displays a welcome screen. Confirm with Enter.
On the next screens, select keyboard, confirm the license agreement and select the time zone.
In the dialog window, enter a password for the
rootand confirm it.
Figure 1: Enter root password #(Optional) To enroll SSH keys for access, press Yes. If you pressed YES, proceed as described below:
Using SSH, connect to the displayed IP address.
If you received a public key properly, confirm it in the next screen.
A prompt to import an SSH key appears. Select the option according to your preferences.
(Optional) If desired, you can create an unprivileged user in the
User Creationform. Fill in the user name, full name and a password twice. Confirm with OK.(Optional) To set up MFA for accessing Cockpit, open a TOTP application and scan the QR code. Enter the OTP value provided by the application. Proceed with OK.
After successful deployment, register your system as described in Section 4.3, “Registering SUSE Linux Micro from CLI”.
4 Post-deployment steps #
4.1 Adding UEFI boot records #
During the deployment, the image of the system is
just copied to the selected disk. Therefore, an EFI boot entry is not
created. You may need to manually boot your system using the EFI
shell by selecting the SUSE Linux Micro boot loader. After the first boot, you can
use efibootmgr to create the boot entry.
efibootmgr is available by default in the deployed
image.
4.2 Adding users #
Since SUSE Linux Micro requires having an unprivileged user to log in via SSH or to access Cockpit by default, we recommend to create such an account.
This step is optional if you have defined an unprivileged user during the deployment of the system. If not, you can proceed as described below:
Run the
useraddcommand as follows:#useradd -m USER_NAMESet a password for that account:
#passwd USER_NAMEIf needed, add the user to the
wheelgroup:#usermod -aG wheel USER_NAME
4.3 Registering SUSE Linux Micro from CLI #
After successful deployment, you need to register the system to get
technical support and receive updates. Registering the system is
possible from the command line using the transactional-update
register command.
To register SUSE Linux Micro with SUSE Customer Center, proceed as follows:
Run
transactional-update registeras follows:#transactional-update register -r REGISTRATION_CODE -e EMAIL_ADDRESSTo register with a local registration server, additionally provide the URL to the server:
#transactional-update register -r REGISTRATION_CODE -e EMAIL_ADDRESS \ --url "https://suse_register.example.com/"Replace REGISTRATION_CODE with the registration code you received with your copy of SUSE Linux Micro. Replace EMAIL_ADDRESS with the e-mail address associated with the SUSE account you or your organization uses to manage subscriptions.
Reboot your system to switch to the latest snapshot.
SUSE Linux Micro is now registered.
For information that goes beyond the scope of this section, refer to the
inline documentation with SUSEConnect --help.
5 Legal Notice #
Copyright© 2006–2025 SUSE LLC and contributors. All rights reserved.
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or (at your option) version 1.3; with the Invariant Section being this copyright notice and license. A copy of the license version 1.2 is included in the section entitled “GNU Free Documentation License”.
For SUSE trademarks, see https://www.suse.com/company/legal/. All other third-party trademarks are the property of their respective owners. Trademark symbols (®, ™ etc.) denote trademarks of SUSE and its affiliates. Asterisks (*) denote third-party trademarks.
All information found in this book has been compiled with utmost attention to detail. However, this does not guarantee complete accuracy. Neither SUSE LLC, its affiliates, the authors, nor the translators shall be held liable for possible errors or the consequences thereof.
GNU Free Documentation License
Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc. 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.
0. PREAMBLE #
The purpose of this License is to make a manual, textbook, or other functional and useful document "free" in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or non-commercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others.
This License is a kind of "copyleft", which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software.
We have designed this License to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference.
1. APPLICABILITY AND DEFINITIONS #
This License applies to any manual or other work, in any medium, that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License. Such a notice grants a world-wide, royalty-free license, unlimited in duration, to use that work under the conditions stated herein. The "Document", below, refers to any such manual or work. Any member of the public is a licensee, and is addressed as "you". You accept the license if you copy, modify or distribute the work in a way requiring permission under copyright law.
A "Modified Version" of the Document means any work containing the Document or a portion of it, either copied verbatim, or with modifications and/or translated into another language.
A "Secondary Section" is a named appendix or a front-matter section of the Document that deals exclusively with the relationship of the publishers or authors of the Document to the Document's overall subject (or to related matters) and contains nothing that could fall directly within that overall subject. (Thus, if the Document is in part a textbook of mathematics, a Secondary Section may not explain any mathematics.) The relationship could be a matter of historical connection with the subject or with related matters, or of legal, commercial, philosophical, ethical or political position regarding them.
The "Invariant Sections" are certain Secondary Sections whose titles are designated, as being those of Invariant Sections, in the notice that says that the Document is released under this License. If a section does not fit the above definition of Secondary then it is not allowed to be designated as Invariant. The Document may contain zero Invariant Sections. If the Document does not identify any Invariant Sections then there are none.
The "Cover Texts" are certain short passages of text that are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the Document is released under this License. A Front-Cover Text may be at most 5 words, and a Back-Cover Text may be at most 25 words.
A "Transparent" copy of the Document means a machine-readable copy, represented in a format whose specification is available to the general public, that is suitable for revising the document straightforwardly with generic text editors or (for images composed of pixels) generic paint programs or (for drawings) some widely available drawing editor, and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters. A copy made in an otherwise Transparent file format whose markup, or absence of markup, has been arranged to thwart or discourage subsequent modification by readers is not Transparent. An image format is not Transparent if used for any substantial amount of text. A copy that is not "Transparent" is called "Opaque".
Examples of suitable formats for Transparent copies include plain ASCII without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML, PostScript or PDF designed for human modification. Examples of transparent image formats include PNG, XCF and JPG. Opaque formats include proprietary formats that can be read and edited only by proprietary word processors, SGML or XML for which the DTD and/or processing tools are not generally available, and the machine-generated HTML, PostScript or PDF produced by some word processors for output purposes only.
The "Title Page" means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, "Title Page" means the text near the most prominent appearance of the work's title, preceding the beginning of the body of the text.
A section "Entitled XYZ" means a named subunit of the Document whose title either is precisely XYZ or contains XYZ in parentheses following text that translates XYZ in another language. (Here XYZ stands for a specific section name mentioned below, such as "Acknowledgements", "Dedications", "Endorsements", or "History".) To "Preserve the Title" of such a section when you modify the Document means that it remains a section "Entitled XYZ" according to this definition.
The Document may include Warranty Disclaimers next to the notice which states that this License applies to the Document. These Warranty Disclaimers are considered to be included by reference in this License, but only as regards disclaiming warranties: any other implication that these Warranty Disclaimers may have is void and has no effect on the meaning of this License.
2. VERBATIM COPYING #
You may copy and distribute the Document in any medium, either commercially or non-commercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this License. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3.
You may also lend copies, under the same conditions stated above, and you may publicly display copies.
3. COPYING IN QUANTITY #
If you publish printed copies (or copies in media that commonly have printed covers) of the Document, numbering more than 100, and the Document's license notice requires Cover Texts, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects.
If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages.
If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a computer-network location from which the general network-using public has access to download using public-standard network protocols a complete Transparent copy of the Document, free of added material. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public.
It is requested, but not required, that you contact the authors of the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document.
4. MODIFICATIONS #
You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version:
Use in the Title Page (and on the covers, if any) a title distinct from that of the Document, and from those of previous versions (which should, if there were any, be listed in the History section of the Document). You may use the same title as a previous version if the original publisher of that version gives permission.
List on the Title Page, as authors, one or more persons or entities responsible for authorship of the modifications in the Modified Version, together with at least five of the principal authors of the Document (all of its principal authors, if it has fewer than five), unless they release you from this requirement.
State on the Title page the name of the publisher of the Modified Version, as the publisher.
Preserve all the copyright notices of the Document.
Add an appropriate copyright notice for your modifications adjacent to the other copyright notices.
Include, immediately after the copyright notices, a license notice giving the public permission to use the Modified Version under the terms of this License, in the form shown in the Addendum below.
Preserve in that license notice the full lists of Invariant Sections and required Cover Texts given in the Document's license notice.
Include an unaltered copy of this License.
Preserve the section Entitled "History", Preserve its Title, and add to it an item stating at least the title, year, new authors, and publisher of the Modified Version as given on the Title Page. If there is no section Entitled "History" in the Document, create one stating the title, year, authors, and publisher of the Document as given on its Title Page, then add an item describing the Modified Version as stated in the previous sentence.
Preserve the network location, if any, given in the Document for public access to a Transparent copy of the Document, and likewise the network locations given in the Document for previous versions it was based on. These may be placed in the "History" section. You may omit a network location for a work that was published at least four years before the Document itself, or if the original publisher of the version it refers to gives permission.
For any section Entitled "Acknowledgements" or "Dedications", Preserve the Title of the section, and preserve in the section all the substance and tone of each of the contributor acknowledgements and/or dedications given therein.
Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles.
Delete any section Entitled "Endorsements". Such a section may not be included in the Modified Version.
Do not retitle any existing section to be Entitled "Endorsements" or to conflict in title with any Invariant Section.
Preserve any Warranty Disclaimers.
If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version's license notice. These titles must be distinct from any other section titles.
You may add a section Entitled "Endorsements", provided it contains nothing but endorsements of your Modified Version by various parties--for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard.
You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one.
The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version.
5. COMBINING DOCUMENTS #
You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice, and that you preserve all their Warranty Disclaimers.
The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work.
In the combination, you must combine any sections Entitled "History" in the various original documents, forming one section Entitled "History"; likewise combine any sections Entitled "Acknowledgements", and any sections Entitled "Dedications". You must delete all sections Entitled "Endorsements".
6. COLLECTIONS OF DOCUMENTS #
You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects.
You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document.
7. AGGREGATION WITH INDEPENDENT WORKS #
A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, is called an "aggregate" if the copyright resulting from the compilation is not used to limit the legal rights of the compilation's users beyond what the individual works permit. When the Document is included in an aggregate, this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document.
If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one half of the entire aggregate, the Document's Cover Texts may be placed on covers that bracket the Document within the aggregate, or the electronic equivalent of covers if the Document is in electronic form. Otherwise they must appear on printed covers that bracket the whole aggregate.
8. TRANSLATION #
Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail.
If a section in the Document is Entitled "Acknowledgements", "Dedications", or "History", the requirement (section 4) to Preserve its Title (section 1) will typically require changing the actual title.
9. TERMINATION #
You may not copy, modify, sublicense, or distribute the Document except as expressly provided for under this License. Any other attempt to copy, modify, sublicense or distribute the Document is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance.
10. FUTURE REVISIONS OF THIS LICENSE #
The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See https://www.gnu.org/copyleft/.
Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License "or any later version" applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation.
ADDENDUM: How to use this License for your documents #
Copyright (c) YEAR YOUR NAME. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled “GNU Free Documentation License”.
If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the “with...Texts.” line with this:
with the Invariant Sections being LIST THEIR TITLES, with the Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST.
If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation.
If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.