Registering RHEL 7 or CentOS Linux 7 with RMT
This guide explains how to register and update RHEL 7 or CentOS Linux 7 with Repository Mirroring Tool (RMT).
To register with SUSE Manager, see Registering RHEL 7 or CentOS Linux 7 with SUSE Manager.
Copyright © 2022–2024 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 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.
1 Introduction #
SUSE Liberty Linux 7 has reached the end of general support and is now in LTSS (Long Term Service Support).
If you have a SUSE Liberty Linux subscription but do not have an LTSS subscription, you can continue to use your systems. However, registering new RHEL 7 or CentOS Linux 7 systems with the general subscription is no longer supported.
To register new RHEL 7 or CentOS Linux 7 systems, and to continue receiving new updates for existing systems, you must use an LTSS subscription.
Additionally, the optional High Availability extension is no longer supported with SUSE Liberty Linux LTSS 7. You must remove this product from your system before you can register with an LTSS subscription.
If you previously registered your systems with a general subscription and want to move them to an LTSS subscription, see Section 4, “Mirroring SUSE Liberty Linux LTSS repositories with RMT” and Section 5, “Registering RHEL or CentOS Linux with RMT”.
SUSE Liberty Linux is a technology and support solution for mixed Linux environments. With a SUSE Liberty Linux subscription, you can register and update Red Hat Enterprise Linux and CentOS Linux.
The following table shows which Linux distributions are supported by each subscription. These subscriptions also include an entitlement for a registration tool to manage package updates.
Subscription | Supported distributions | Registration options |
---|---|---|
SUSE Liberty Linux Enterprise |
CentOS Linux Red Hat Enterprise Linux SUSE Linux Enterprise Server |
SUSE Manager Repository Mirroring Tool |
SUSE Liberty Linux Professional |
CentOS Linux Red Hat Enterprise Linux | SUSE Manager |
SUSE Liberty Linux Basic | CentOS Linux | SUSE Manager |
SUSE Liberty Linux Lite |
CentOS Linux Includes one entitlement for SLES to host RMT | Repository Mirroring Tool |
CentOS Stream is not supported.
Registering RHEL or CentOS Linux directly with SUSE Customer Center is not currently supported.
This guide describes how to register with Repository Mirroring Tool (RMT). RMT is a proxy system for SUSE Customer Center. The RMT server is registered with SUSE Customer Center, and other systems are registered with the RMT server and receive packages from it directly.
To register with SUSE Manager, see Registering RHEL 7 or CentOS Linux 7 with SUSE Manager.
If you already have an RMT server and only need to register your RHEL 7 or CentOS Linux 7 system, skip straight to Section 5, “Registering RHEL or CentOS Linux with RMT”.
If you already have an RMT server but still need to mirror the SUSE Liberty Linux LTSS 7 repositories, go to Section 4, “Mirroring SUSE Liberty Linux LTSS repositories with RMT”.
If you still need to set up the RMT server, start with Section 2, “Installing a virtual machine to host RMT” and Section 3, “Configuring the RMT server”.
SUSE Liberty Linux now provides what used to be covered by the SUSE Linux Enterprise Server with Expanded Support subscription. Some components might still use the Expanded Support name during the transition period.
2 Installing a virtual machine to host RMT #
Use this procedure to install a SLES Minimal VM, a preconfigured virtual machine image that contains a slimmed-down version of SUSE Linux Enterprise Server (SLES). This machine will be the Repository Mirroring Tool (RMT) server.
You can use your SUSE Liberty Linux Lite or Enterprise subscription to register this machine. Basic and Professional do not include an entitlement for SLES, so you will need a separate SLES subscription if you want to use RMT instead of SUSE Manager.
To install a full SLES machine on bare metal, see Installation Quick Start.
To deploy SLES in the public cloud, see Deploying a SUSE Linux Enterprise Server instance to support RMT in the public cloud in Repository Mirroring Tool Guide.
You have a SUSE Liberty Linux subscription.
You have a SUSE Customer Center account.
The VM must have a static IP address and host name. This guide includes steps for configuring the VM's network setup, but you must have basic networking knowledge to fill in the details.
You have the infrastructure to run virtual machines. This guide explains how to set up the VM to host RMT, but does not describe how to use different virtualization products. See the relevant documentation for your product.
The RMT server needs enough available disk space to mirror the SUSE Liberty Linux LTSS 7 repositories. Downloaded packages are stored in
/var/lib/rmt/public/repo/
. The amount of storage required depends on the number of repositories you mirror. We recommend at least 1.5 times the total size of all enabled repositories.Important: SUSE Liberty Linux LTSS 7 repository sizeThe SUSE Liberty Linux LTSS 7 repositories will grow over time because older package versions are not removed. Based on the current[1] size of the repositories, to meet the 1.5 times size recommendation you will need approximately 15 GB of disk space for the default
LTSS-Updates
repository. If you need the optionalLTSS-Source
andLTSS-Debug
repositories, you will need an additional 39 GB.SUSE Liberty Linux LTSS 7 also has optional frozen
BASE
repositories that contain the packages from the non-LTSS repositories. If you need these repositories, to meet the 1.5 times size recommendation you will need approximately 210 GB for theBASE-Updates
repository and 730 GB for theBASE-Source
andBASE-Debug
repositories.
Download the appropriate
Minimal-VM
image for your virtualization infrastructure from https://www.suse.com/download/sles/.Use the
Minimal-VM
image to start the virtual machine.The default disk size for SLES Minimal VM is 24 GB. If you can customize the configuration before the installation begins, increase the available storage so there is enough disk space for repository mirroring.
When the
JeOS Firstboot
screen appears, select .Choose your keyboard layout and select
.Review the
End User License Agreement
and select . To agree with the terms of the license, select .Choose your time zone and select
.Enter a
root
password and select , then confirm the password and select again.JeOS Firstboot shows the command to use to register this VM. You do not need to write this down; the command is explained in this procedure. Select
.When the VM is ready, log in as the
root
user with the password you entered during setup.Register the VM using your SUSE Customer Center email address and the registration code for SUSE Liberty Linux:
#
SUSEConnect -e EMAIL_ADDRESS -r REGISTRATION_CODE
This activates the
Basesystem
,Server Applications
, andPython 3
modules.If you did not already increase the VM's disk space before the installation began, increase it now. You might need to shut down the VM to do so. The VM must have enough space to mirror the SUSE Liberty Linux LTSS 7 repositories.
You must also configure a static IP address and host name for the VM. If you are familiar with any networking tools in SLES, configure the network with your preferred tool. If not, use the YaST graphical interface:
Install YaST and the YaST
network
module:#
zypper install yast2 yast2-network
Start the YaST
network
module:#
yast2 lan
In the
tab, select to change the settings of theeth0
device. The dialog opens.In the
tab, activate .Fill in the
, , and fields.Select
.Switch to the
tab and fill in the field.Change
tono
.Fill in at least one
field.Switch to the
tab and select . A new dialog opens.Fill in the
field. Make sure to remove the-
character.From the
drop-down list, selecteth0
.Select
to close the dialog.Select
to complete the configuration and close YaST.Check the network settings:
#
ip addr
Check that the network interface can access external networks:
#
ping www.suse.com
Cancel the ping with Ctrl–C.
You can now install RMT on the virtual machine.
3 Configuring the RMT server #
Use this procedure to configure the Repository Mirroring Tool (RMT) on SUSE Linux Enterprise Server (SLES) 15.
A SLES 15 virtual machine is installed as described in Section 2, “Installing a virtual machine to host RMT”.
The SLES machine has a static IP address and host name.
You have a SUSE Customer Center account and organization credentials.
On the SLES machine, install RMT:
#
zypper install rmt-server
Install the following packages, which are not installed by default on a SLES Minimal VM:
#
zypper install yast2-rmt mariadb nginx
Start the YaST
rmt
module:#
yast2 rmt
Enter your
, then select .To find your organization credentials, log in to SUSE Customer Center, select your organization from , and click . Your organization's are in the top right corner.
Enter
for a new MariaDB database user, then select . The new user is created.When prompted, enter and confirm a new password for the MariaDB root user, then select
.Enter a
for the SSL certificates. The common name is usually the host name of the server.If the server has other domain names or IP addresses, enter these as
. Select to add new names. When all common names are entered, select .If prompted, enter and confirm a password for the CA private key, then select
.Activate the check box
, then select .YaST displays the
. If there are no issues, select .Review the
, then select to close YaST.
YaST enables and starts all RMT systemd
services and timers.
4 Mirroring SUSE Liberty Linux LTSS repositories with RMT #
Use this procedure to mirror the SUSE Liberty Linux LTSS repositories for Red Hat Enterprise Linux 7 and CentOS Linux 7.
The RMT server is installed and up to date.
The RMT server has enough storage available for repository mirroring. The amount of storage required depends on the number of repositories you mirror. We recommend at least 1.5 times the total size of all enabled repositories. Be aware that the SUSE Liberty Linux LTSS repositories will grow over time.
Your organization credentials appear correctly in
/etc/rmt.conf
.You have a SUSE Liberty Linux subscription activated in SUSE Customer Center.
The repository structure has changed in SUSE Liberty Linux LTSS 7. The non-LTSS subscription
had one default repository and one optional Source
repository. The LTSS
subscription has a default LTSS-Updates
repository, an optional
BASE-Updates
repository, and optional Source
and
Debug
repositories for both LTSS
and BASE
.
BASE
repositories are frozen and contain the existing packages from the
non-LTSS repositories. LTSS
repositories contain new packages for
SUSE Liberty Linux LTSS 7.
There are no new High Availability repositories. High Availability is not supported with SUSE Liberty Linux LTSS 7.
If you previously mirrored the SUSE Liberty Linux repositories with the general subscription, clean up these repositories first before you start mirroring the new LTSS repositories:
Disable the original product. This also disables all repositories associated with the product:
#
rmt-cli products disable 1251
If your previous subscription included the High Availability extension, disable this product too:
#
rmt-cli products disable 1252
High Availability is not supported with SUSE Liberty Linux LTSS 7.
Free up space on the server by cleaning up the files associated with the disabled repositories:
#
rmt-cli repos clean
On the RMT server, update the available product and repository metadata:
#
rmt-cli sync
Synchronization is also performed automatically by
rmt-server-sync.timer
. You can check the status and the next scheduled synchronization time with the following command:#
systemctl status rmt-server-sync.timer
Enable SUSE Liberty Linux LTSS 7 using the product ID
2702
:#
rmt-cli products enable 2702
This enables the default
RES-7-LTSS-Updates
repository.If you also need the
BASE
,Source
orDebug
repositories, enable them with the following commands:RES-7-BASE-Updates
:#
rmt-cli repos enable 6986
RES-7-LTSS-Source-Updates
andRES-7-BASE-Source-Updates
:#
rmt-cli repos enable 6748 6987
RES-7-LTSS-Debug-Updates
andRES-7-BASE-Debug-Updates
:#
rmt-cli repos enable 6985 6988
BASE
repositories are frozen and contain the existing packages from the non-LTSS SUSE Liberty Linux repositories.LTSS
repositories contain new packages for SUSE Liberty Linux LTSS 7.Start package mirroring for the enabled repositories:
#
rmt-cli mirror
Packages are downloaded to the RMT server once per day by
rmt-server-mirror.timer
. You can check the status and the next scheduled download time with the following command:#
systemctl status rmt-server-mirror.timer
5 Registering RHEL or CentOS Linux with RMT #
Use this procedure to register Red Hat Enterprise Linux 7 or CentOS Linux 7 with the RMT server.
CentOS Stream is not supported.
The RMT server is running rmt-server version 2.18 or later.
The SUSE Liberty Linux LTSS 7 repositories are available on the RMT server.
The system you want to register can access the RMT server.
The system you want to register is up to date. SUSE Liberty Linux only supports the latest minor release of RHEL 7 or CentOS Linux 7.
You have a SUSE Liberty Linux subscription activated in SUSE Customer Center.
You have removed the system from any Red Hat subscription services it was registered to.
The repository structure and registration setup has changed in SUSE Liberty Linux LTSS 7. If you previously registered your system with a general SUSE Liberty Linux subscription, de-register your system from the original subscription before you re-register with the LTSS subscription:
De-register your system:
#
SUSEConnect --de-register
This command also removes the High Availability extension if it was installed on your system. High Availability is not supported with SUSE Liberty Linux LTSS 7.
Clean up the registration status:
#
SUSEConnect --cleanup
Download the
rmt-client-setup-res
script:#
curl http://RMT_SERVER/tools/rmt-client-setup-res --output rmt-client-setup-res
Run the
rmt-client-setup-res
script with the URL of the RMT server as a parameter:#
sh rmt-client-setup-res https://RMT_SERVER
The script installs
SUSEConnect
and its dependencies, then downloads and runs thermt-client-setup
script, which performs the following tasks:Downloads all keys from
http://RMT_SERVER/repo/keys
.Imports the keys with
gpg --import
andrpm --import
.Downloads the CA certificate from
https://RMT_SERVER/rmt.crt
.Imports the CA certificate to the trust store.
Uses
SUSEConnect
to register the system with the RMT server. Registering the system usingSUSEConnect
adds and enables all default repositories.
You should see
Successfully registered system
.Verify the installed product:
#
SUSEConnect --status-text
You should see the following output:
Installed Products: ------------------------------------------ SUSE Liberty Linux release file (RES-LTSS/7/x86_64) Registered ------------------------------------------
Verify the available repositories:
#
yum repolist all
The default repository
RES-7-LTSS-Updates
should beenabled
.You will also see optional
BASE
,Source
andDebug
repositories with the statusdisabled
. Be aware that these repositories are listed even if they are not mirrored on the RMT server. You can check the mirrored repositories by browsing the directory listing athttps://RMT_SERVER/repo/SUSE/Updates/
or by logging in to the RMT server and runningrmt-cli repos list
.BASE
repositories are frozen and contain the existing packages from the non-LTSS SUSE Liberty Linux repositories.LTSS
repositories contain new packages for SUSE Liberty Linux LTSS 7.(Optional) If you need any of the
BASE
,Source
orDebug
repositories, enable them with the following command:#
yum-config-manager --enable REPO_ID
Run the update command to make sure there are no errors:
#
yum update
You can now keep your system up to date from repositories provided by SUSE Liberty Linux.
6 Troubleshooting #
nginx.service
is inactive after installing the rmt-server packageContinue the procedure to configure RMT in YaST. This often resolves the issue. If that fails, Apache might be installed on your server, and must be disabled. Apache conflicts with NGINX because both web servers listen on port 80.
- SUSE Liberty Linux does not appear in
rmt-cli products list
afterrmt-cli sync
Check your network. If the network is down,
rmt-cli sync
fails without showing an error.- Mirroring completes with errors
If some packages could not be downloaded because of timeouts, rerun the
rmt-cli mirror
command until all packages are downloaded.- Setup script cannot access the SUSE Liberty Linux repositories
The
repodata
directory on the RMT server will not be available until all of the packages for that repository are downloaded. If some packages could not be downloaded to the RMT server because of timeouts during the first mirroring, rerun thermt-cli mirror
command until all packages are downloaded.- Setup script cannot install suseconnect-ng because of package dependencies
SUSE Liberty Linux only supports the latest minor release of RHEL or CentOS Linux. If your system is running the latest version and suseconnect-ng still has package dependency issues, try the following workaround:
Edit the
rmt-client-setup-res
script to add--skip-broken
to the following line:$YUM install sles_es-release-server suseconnect-ng librepo --skip-broken
Run the script and accept any proposed package changes. suseconnect-ng will be skipped.
Run the script a second time. The package changes from the first attempt can sometimes resolve the package dependency issues, allowing the second attempt to successfully install suseconnect-ng.
yum update
fails with[Errno 14] HTTPS Error 404 - Not Found
The repository shown in the error message might not be mirrored on the RMT server. The optional
BASE
,Source
andDebug
repositories can be enabled withyum-config-manager
even if they are not available from RMT.Run
yum repolist all
to show the status of the repositories.If the repository shown in the error message has the status
enabled
, disable it with the following command:#
yum-config-manager --disable REPO_ID
Run
yum update
again to see if the issue is resolved.If you need the unavailable repository for your system, see Section 4, “Mirroring SUSE Liberty Linux LTSS repositories with RMT”.
A GNU licenses #
This appendix contains the GNU Free Documentation License version 1.2.
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.