Using the koji build system

Using Koji in Fedora

The Koji Build System is Fedora’s RPM buildsystem. Packagers use the koji client to request package builds and get information about the buildsystem. Koji runs on top of Mock to build RPM packages for specific architectures and ensure that they build correctly.

Installing Koji

Installing the Koji CLI

Everything you need to use Koji (and be a Fedora contributor) can be installed in a single step:

dnf install fedora-packager

fedora-packager provides useful scripts to help maintain and setup your koji environment. Additionally, it includes dependencies on the Koji CLI, so it will be installed when you install fedora-packager. The command is called koji and is included in the main koji package. By default the koji tool authenticates to the central server using Kerberos. However SSL and username/password authentications are available. You will need to have a valid authentication token to use many features. However, many of the read-only commands will work without authentication.

If you run into any problems with Fedora’s instance of koji, here is actual documentation for installing and using developer client tools.

Alternatively, koji CLI is now also available via:

  • Project releases tarballs Preferred way is to use your distribution’s mechanism instead, as it will also contain appropriate configuration files.

  • PyPi There is only client/API part and it is mostly usable for people who wants some more advanced client-side scripting in virtualenv’s, so API-only access is not sufficient for them or who can profit from some utilities in e.g. basic koji library.

  • Actual development version via Pagure’s git: git clone

Koji Config

The global local client configuration file for koji is /etc/koji.conf. You should not need to change this from the defaults for building Fedora packages.These will allow you to use the primary build system as well as secondary arch build systems.

The web interface

The primary interface for viewing Koji data is a web application. It is available at . Most of the interface is read-only, but with sufficient privileges, you can log in and perform some additional actions. For example:

  • Cancel a build

  • Resubmit a failed task

  • Setup a notification

Those with admin privileges will find additional actions, such as:

  • Create/Edit/Delete a tag

  • Create/Edit/Delete a target

  • Enable/Disable a build host

The web site utilizes SSL authentication. In order to log in you will need a valid SSL certificate and your web browser will need to be configured to trust the SSL cert. Instructions on how to do this are printed when running fedora-packager-setup --with-browser-cert.

Installing SSL Certificates in Firefox

Once you have created your FAS account, generated your certificate in the form posted in the link above and ran fedora-packager-setup --with-browser-cert, you will need to import it into your web browser. You can do this in Firefox by doing the following:

  1. Launch Firefox and click on the Edit menu from the toolbar

  2. Select Preferences in the sub-menu which appears.

3. This should open the Preferences window where you can switch to the Advanced section

  1. In the Advanced section switch to the Encryption tab

5. Click on the View Certificates button and the Certificates window will appear

6. Switch to the Your Certificates tab and click on the Import button

7. Point to where your Fedora Certificate is located and click Open (fedora-packager-setup will have told you where it was saved and will have asked you to set a password for the cert)

You should now be able to see your Fedora Certificate listed under Your Certificates and you should be able to authenticate with the koji web interface.

Installing SSL Certificates in Chromium

Chromium uses the NSS Shared DB, you will need the nss-tools package installed.

pk12util -d sql:$HOME/.pki/nssdb -i fedora-browser-cert.p12


Koji supports a limited number of email notifications:

  • build notifications: when builds complete or fail

  • tag notifications: when builds are tagged or untagged

These mails are sent to:

  • the owner of the build in question

  • (for tag notifications) the owner of the package for the tag

  • any user who as subscribed to notifications for that package or tag

Users can manage their notification subscriptions in the web interface. To do so, they need to be logged in. The main page (Summary) will list their subscriptions at the bottom. Each entry includes an “edit” and “delete” link. Below that table is an “Add a notification” link for adding new notifications.

Starting in Koji version 1.16.0, users can also manage these subscriptions on the command line. The relevant commands are:

  • add-notification

  • edit-notification

  • list-notifications

  • remove-notification

Building with fedpkg targets

Every push is automatically tagged via git. All you have done to build the package is to run,

fedpkg build

This will trigger a build request for the branch. Easy!

It is also possible to target a specific koji tag as follows:

fedpkg build --target TARGET

for example, if building on rawhide against a special tag created by rel-eng for updating API for many packages, e.g. dist-f14-python you would use the following:

fedpkg build --target 'dist-f14-python'

Chained builds

Sometimes you want to make sure than one build succeeded before launching the next one, for example when you want to rebuild a package against a just rebuilt dependency. In that case you can use a chain build with:

fedpkg chain-build libwidget libgizmo

The current package is added to the end of the CHAIN list. Colons (:) can be used in the CHAIN parameter to define groups of packages. Packages in any single group will be built in parallel and all packages in a group must build successfully and populate the repository before the next group will begin building. For example:

fedpkg chain-build libwidget libaselib : libgizmo :

will cause libwidget and libaselib to be built in parallel, followed by libgizmo and then the correct directory package. If no groups are defined, packages will be built sequentially.

If a build fail, following builds are cancelled but the builds that already succeeded are pushed to the repository.

Scratch Builds

Sometimes it is useful to be able to build a package against the buildroot but without actually including it in the release. This is called a scratch build. The following section covers using koji directly as well as the fedpkg tool to do scratch builds. To create a scratch build from changes you haven’t committed, do the following:

rpmbuild -bs foo.spec
koji build --scratch rawhide foo.srpm

From the latest git commit:

koji build --scratch rawhide 'git url'

Warning: Scratch builds will not work correctly if your .spec file does something different depending on the value of %fedora, %fc9, and so on. Macro values like these are set by the builder, not by koji, so the value of %fedora will be for whatever created the source RPM, and not what it’s being built on. Non-scratch builds get around this by first re-building the source RPM.

If you have committed the changes to git and you are in the current branch, you can do a scratch build with fedpkg tool which wraps the koji command line tool with the appropriate options:

fedpkg scratch-build

if you want to do a scratch build for a specific architecture, you can type:

   fedpkg scratch-build-<archs>

can be a comma separated list of several architectures.

finally is possible to combine the scratch-build command with a specific koji tag in the form:

fedpkg scratch-build --target TARGET

fedpkg scratch-build –help or koji build –help for more information.

Build Failures

If your package fails to build, you will see something like this:

420066 buildArch kernel-2.6.18-1.2739.10.9.el5.jjf.215394.2.src.rpm,
ia64): open ( -> FAILED: BuildrootError:
error building package (arch ia64), mock exited with status 10

You can figure out why the build failed by looking at the log files. If there is a build.log, start there. Otherwise, look at init.log.

Logs can be found via the web interface in the Task pages for the failed task. Alternatively the koji client can be used to view the logs via the watch-logs command. See the help output for more details.

Advanced use of Koji

We’ve tried to make Koji self-documenting wherever possible. The command line tool will print a list of valid commands and each command supports –help. For example:

$ koji help

Koji commands are:
build                Build a package from source
cancel-task          Cancel a task
help                 List available commands
latest-build         Print the latest builds for a tag
$ koji build --help

usage: koji build [options]  tag URL
(Specify the --help global option for a list of other help options)

-h, --help            show this help message and exit
--skip-tag            Do not attempt to tag package
--scratch             Perform a scratch build
--nowait              Don't wait on build

Using koji to generate a mock config to replicate a buildroot

koji can be used to replicate a build root for local debugging

koji mock-config --help
Usage: koji mock-config [options] name
(Specify the --help global option for a list of other help options)

  -h, --help            show this help message and exit
  --arch=ARCH           Specify the arch
  --tag=TAG             Create a mock config for a tag
  --task=TASK           Duplicate the mock config of a previous task
                        Duplicate the mock config for the specified buildroot
  --mockdir=DIR         Specify mockdir
  --topdir=DIR          Specify topdir
  --topurl=URL          url under which Koji files are accessible
                        Change the distribution macro
  -o FILE               Output to a file

for example to get the latest buildroot for dist-f12-build run

koji mock-config --tag dist-f12-build --arch=x86_64 --topurl= dist-f12

you will need to pass in –topurl= to any mock-config command to get a working mock-config from fedoras koji.

Tuning mock’s behavior per tag

Few options for mock can be configured per-tag. These options are stored in tag info’s extra field. Extra values can be checked via koji taginfo command. Example for forcing dnf usage in specific build environment follows:

koji edit-tag dnf-fedora-tag -x mock.package_manager=dnf
  • mock.package_manager - If this is set, it will override mock’s default package manager. Typically used with yum or dnf values.

  • mock.new_chroot - 0/1 value. If it is set, --new-chroot or –old-chroot option is appended to any mock call. If it is not set, mock’s default behavior is used.

  • mock.releasever - When doing cross-compiles it may be necessary to explicitly set the releasever to be used.

  • mock.use_bootstrap - 0/1 value. If it is set, --bootstrap-chroot is appended to the mock init call. This tells mock to build in two stages, using chroot rpm for creating the build chroot. If it is not set, mock’s default behaviour is used. (Note, that it changed in mock 1.4.1. Note, that it is not turn on by default by koji, as it is often not needed and it consumes additional resources (larger buildroot, downloading more data).

  • mock.bootstrap_image - set to name of image, which can builder’s podman download (e.g. fedora:32). See mock’s doc before using this. You could need it, but do it with following recommendations:

    • you need to explicitly allow builders to do that (mock_bootstrap_image = True in kojid.conf).

    • you need to have builders with podman installed and working.

    • use concrete hashes not potentially moving tags. Otherwise, you can get into harder debugging and auditing.

    • builders can consume space during time, no cleanup is made for podman’s image cache. So, you’ll probably want to run something like podman rmi `podman images -a --quiet` periodically via cron or use some other cache-cleaning mechanism. Even simple task will consume roughly three times more space than without bootstrap image (downloaded image + exploded bootstrap dir + mock’s buildroot itself)

    • be sure, that your podman is configured properly and it downloads images only from trusted sources. Note, that this setting effectivelly circumvents network isolation inside buildroot, as outside DNS, etc. can be spoofed.

    • this option will automatically turn mock.use_bootstrap (this is how it is implemented in mock)

  • mock.module_setup_commands - commands for configuring the modules active in a buildroot. Available in mock 2.4.

    • Example of how to enable a module:

    koji edit-tag dnf-fedora-tag -x mock.module_setup_commands='[["enable", "<module_name>"]]'
  • mock.forcearch - 0/1 value. If true mock will set the forcearch config option to match the target arch of each buildroot.

  • - 0/1 value. If set yum/dnf will use highest available rpm version (see man yum.conf)

  • mock.yum.module_hotfixes - 0/1 value. If set, yum/dnf will use packages regardless if they come from modularity repo or not. It makes sense only for tags with external repositories. (See dnf docs)

  • mock signing plugin - Options mock.plugin_conf.sign_enable, mock.plugin_conf.sign_opts.cmd and mock.plugin_conf.sign_opts.opts are propagated to mock conf to be used by this plugin. Note, that these tools are run outside of the jailed env. Note, that this functionality doesn’t interfere with koji’s standard signing commands (import-sig, write-signed-rpm, etc.). Note, that rpmsign vs gpg must be configured correctly. If it is not it a) can silently ignore problems during signing b) can hang forever when e.g. gpg password store is not accessible.

You may also specify per-tag environment variables for mock to use. For example, to set the CC environment variable to clang, you could do:

koji edit-tag dnf-fedora-tag -x rpm.env.CC=clang

Using Koji to control tasks

List tasks:

koji list-tasks

List only tasks requested by you:

koji list-tasks --mine

requeue an already-processed task: general syntax is: koji resubmit [options] taskID

koji resubmit 3

Building a Package with the command-line tool

Instead of using the fedpkg target, you can also directly use the command_line tool, koji.

To build a package, the syntax is:

$ koji build <build target> <git URL>

For example:

$ koji build dist-f14 'git url'

The koji build command creates a build task in Koji. By default the tool will wait and print status updates until the build completes. You can override this with the –nowait option.

NOTE: For fedora koji, the git url MUST be based on Other arbitrary git repos cannot be used for builds.

Koji tags and packages organization


In Koji, it is sometimes necessary to distinguish between a package in general, a specific build of a package, and the various rpm files created by a build. When precision is needed, these terms should be interpreted as follows:

  • Package: The name of a source rpm. This refers to the package in general and not any particular build or subpackage. For example: kernel, glibc, etc.

  • Build: A particular build of a package. This refers to the entire build: all arches and subpackages. For example: kernel-2.6.9-34.EL, glibc-2.3.4-2.19.

  • RPM: A particular rpm. A specific arch and subpackage of a build. For example: kernel-2.6.9-34.EL.x86_64, kernel-devel-2.6.9-34.EL.s390, glibc-2.3.4-2.19.i686, glibc-common-2.3.4-2.19.ia64

Tags and targets

Koji organizes packages using tags. In Koji a tag is roughly a collection of packages:

  • Tags support inheritance

  • Each tag has its own list of valid packages (inheritable)

  • Package ownership can be set per-tag (inheritable)

  • When you build you specify a target rather than a tag

A build target specifies where a package should be built and how it should be tagged afterwards. This allows target names to remain fixed as tags change through releases.

Koji commands for tags


You can get a full list of build targets with the following command:

$ koji list-targets

You can see just a single target with the –name option:

$ koji list-targets --name dist-f14

Name                           Buildroot                      Destination
dist-f14                     dist-f14-build                 dist-f14

This tells you a build for target dist-f14 will use a buildroot with packages from the tag dist-f14-build and tag the resulting packages as dist-f14.

Watch out: You probably don’t want to build against dist-rawhide. If Fedora N is the latest one out, to build to the next one, choose dist-f{N+1}.


You can get a list of tags with the following command:

$ koji list-tags

As mentioned above, each tag has its own list of packages that may be placed in the tag. To see that list for a tag, use the list-pkgs command:

$ koji list-pkgs --tag dist-f14

The first column is the name of the package, the second tells you which tag the package entry has been inherited from, and the third tells you the owner of the package.

Latest Builds

To see the latest builds for a tag, use the latest-build command:

$ koji latest-build --all dist-f14

The output gives you not only the latest builds, but which tag they have been inherited from and who built them.

Category:Package Maintainers


All features supported by command-line client are also accessible by XMLRPC API. You can get listing of all available calls, arguments and basic help via calling koji list-api command. This call will also provide you API extensions provided by plugins in that particular koji instance.

Because of the data Koji routinely deals with, we use the following extensions to the xmlrpc standard:

  • We use the nil extension to represent null values (e.g. None in Python). Koji’s library handles this automatically. If you are using a different library, you may need to explicitly enable this (e.g. enabling allow_none in Python’s own xmlrpc library).

  • We represent large integers with the i8 tag. This standard is borrowed from Apache’s ws-xmlrpc <> implementation. Python’s own xmlrpc library understands this tag, even thought it will not emit it.

  • For encoding python-like optional arguments (**kwargs) we introduced dictionary in xmlrpc request called __starstar. It is marked by member boolean variable __starstar = True.

So, full example of XML document for hypothetical call Method("a", token=1, null_value=None, large=10**10) would look like:

<?xml version='1.0'?>