How to use and edit comps.xml for package groups

How comps is used

Installation

comps is used by the installer during software selection. At the installer software selection dialog, the user can choose between a variety of Environments on the left, and Options to those environments on the right.

Each environment consists of a list of groups, and a list of groups that are options for that environment. The list of available options is supplemented by any groups that are marked as 'uservisible' in the comps file.

Running System

In dnf, groups are used by:

dnf [options] group [summary] <group-spec>

Display overview of how many groups are installed and available. With a spec, limit the output to the matching groups. summary is the default groups subcommand.

dnf [options] group info <group-spec>

Display package lists of a group. Shows which packages are installed or available from a repo when -v is used.

dnf [options] group install [--with-optional] <group-spec>...

Mark the specified group installed and install packages it contains. Also include optional packages of the group if --with-optional is specified.

dnf [options] group list <group-spec>...

List all matching groups, either among installed or available groups. If nothing is specified list all known groups. Records are ordered by display_order tag defined in comps.xml file.

dnf [options] group remove <group-spec>...

Mark the group removed and remove those packages in the group from the system which are neither comprising another installed group and were not installed explicitly by the user.

dnf [options] group upgrade <group-spec>...

Upgrades the packages from the group and upgrades the group itself. The latter comprises of installing pacakges that were added to the group by the distribution and removing packages that got removed from the group as far as they were not installed explicitly by the user.

Groups can be also be marked installed or removed without physically manipualting any packages:

dnf [options] group mark install <group-spec>...

Mark the specified group installed. No packages will be installed by this command but the group is then considered installed.

dnf [options] group mark remove <group-spec>...

Mark the specified group removed. No packages will be removed by this command.

Tree, Release, and Image Composition

The kickstart files in fedora-kickstarts use the group definitions from comps to compose images and release trees.

Environment definitions should not be used in a kickstart, if you wish to use the environment of "Minimal Install" it should be the list of package groups that comprise the enviornment instead as such: @standard @guest-agents

This is found in the comps.xml under the environment you wish to use.

Comps structure

COMPS are composed from elements and flags

Comps element - environment

Environmental group is composed of list of mandatory groups and optional groups. Mandatory groups have to be installed for successful install of environmental group.

 <environment>
  <id>env1</id>
  <name>Env One</name>
   <grouplist>
     <groupid>group1</groupid>
   </grouplist>
   <optionlist>
     <groupid>group2</groupid>
   </optionlist>
 </environment>

Comps element - group

Groups are composed from list of packages of four types (see Comps element - package)

Comps element - package

There are four types of packages

• mandatory
  • have to be installed to mark group as installed
  • are essential for functionality of a group
• default
  • are installed with mandatory packages, but can be excluded
  • are not essential for core functionality of a group
• optional
  • are not installed by default
  • can be added to transaction dnf group install –with-optional ‘Group One’
• conditional
  • are brought in transaction if their required package is installed or about to be installed

Package basearchonly flag

To make COMPS more adjustable it possible to use basearchonly flag that force package manager to install package only for system base-arch. If package with basearchonly="true" cannot be installed with basearch then the package should not be installed at all, therefore in case of mandatory package, install of the group should be unsuccessful. The absence of basearchonly flag is equivalent to basearchonly="False", where the package can be installed with any compatible architecture.

Comps element - arch flag

Each comps element can be used with arch flag to determine on which system should be element take in account. The arch values are compared with basearch value of system. The absence of arch flag means that comps element is valid for all architectures. Like if I have <packagereq type="mandatory" arch="i686,s390">pkg-c</packagereq> in comps the package will be installed only on systems with basearch i686 or s390. It means that the pkg-c will be even not installed on system with compatible architecture like x86_64.

Examples

 <group>
   <id>group1</id>
   <name>Group One</name>
   <packagelist>
     <packagereq type="mandatory">pkg-a</packagereq>
     <packagereq type="default">pkg-b</packagereq>
     <packagereq type="default" basearchonly="true">pkg-c</packagereq>
     <packagereq type="optional">pkg-d</packagereq>
   </packagelist>
 </group>

When to submit changes to comps

• If your app should be part of one of the installation environments, or part of an option for one of them, it should be included
• If you're creating a new option for an installation environment
• Libraries should not be included - they will be pulled in via dependencies
• Most text-mode utilities don't really fit in unless they have a pretty large established user-base.

If you have questions as to whether it makes sense or not, feel free to post to the development list.

Some guidelines on specific groups in comps follows.

New groups

Please consult devel before adding new groups.

New user-visible group names and descriptions are translatable strings. Do not add new groups, or change their descriptions, during a string freeze. Please check the release schedule for these dates.

Core

Core is not visible, so adding 'default' or 'optional' packages to it isn't needed. Boot loaders are listed as 'default' in the group so that they're pulled in by compose tools.

Core is installed on every installation, so adding packages to it is discouraged. Please run changes by the Minimal Core SIG.

GNOME Desktop

The gnome-desktop group and GNOME environment definition is maintained by the Desktop SIG. Please run changes through desktop.

KDE Desktop

The kde-desktop group and KDE environment definition is maintained by the KDE SIG. Please run changes by them.

Fonts

The following is part of the Fonts SIG packaging rules.

Fonts for a particular linguistic region used to be bundled in fonts-region packages. Nowadays this practice is frowned upon, fonts package naming reflects upstream naming like in any other Fedora package, and grouping is achieved through comps groups.

• Font packages in a legacy format (not TTF or OTF) MUST be registered in the legacy-fonts group.
• Font packages in a non-legacy format (TTF or OTF):
  1. MUST be registered in the fonts group:
     • except when they don't have an active upstream, in which case putting them in legacy-fonts is fine.
  2. SHOULD also be registered in every applicable xxx-support localization group:
     • except groups that only require glyphs in the basic latin range.
     • if a font package adds support for a script previously not supported by Fedora the associated localization groups MUST be created and filed, and the relevant localization teams notified.
  3. SHOULD be declared optional, unless:
     • they add support for a new script, in which case they MUST be declared required in the associated localization groups.
     • they add better support for already supported scripts, in which case, if the localization team in charge of each localization group agrees:
       • they can replace existing fonts as mandatory if this script is not covered by distribution-wide default fonts.
       • they can replace existing fonts as default if this script is covered by distribution-wide default fonts.

Fonts in Fedora
The Fonts SIG takes loving care of Fedora fonts. Please join this special interest group if you are interested in creating, improving, packaging, or just suggesting a font. Any help will be appreciated.

All other groups

When making changes to the default or mandatory packages, strive for consensus, and consult the development lists as necessary. If you're unsure, you can also file a bug against the comps component in bugzilla.

How to submit changes to comps

Fork the fedora-comps git module in Pagure at https://pagure.io/fedora-comps. Then you can clone your fork:

git clone ssh://git@pagure.io/forks/<username>/fedora-comps.git

Substitute your FAS username for <username> above. Then checkout a branch, using whatever name you prefer (a descriptive name is helpful):

git checkout -b <branch-name>

Then, find a reasonable group in the comps-fnxml.in file (where n represents the release number) for your package. If your package is not listed there, please add it using the following as a template if your package were named "foo":

<packagereq type="optional">foo</packagereq>

• Make sure to preserve the alphabetical order in each group.
• Make sure to run xmllint on the result to check you didn't make a mistake in the XML syntax.

You can use the provided xslt filter to sort, indent and check the syntax of your comps file in one run:

$ xsltproc --novalid -o sorted-file comps-cleanup.xsl original-file

The filter will warn you if it removes redundant information or if something needs to be checked by a human.

Commit your changes (git commit -a). You can then push your changes to the repository with git push origin <branch-name>.

You can then file a pull request from your new branch in the Pagure interface.

Current status

You can check our current comps status file in the git web interface.