README.rst

The Module Build Service (MBS) for Modularity

The MBS coordinates module builds and is responsible for a number of tasks:

  • Providing an interface for module client-side tooling via which module build submission and build state queries are possible.
  • Verifying the input data (modulemd, RPM SPEC files and others) is available and correct.
  • Preparing the build environment in the supported build systems, such as koji.
  • Scheduling and building of the module components and tracking the build state.
  • Emitting bus messages about all state changes so that other infrastructure services can pick up the work.

Documentation

For our documentation, see docs.

Change Log

For a detailed change log, see docs/CHANGELOG.rst.

Contributing

For detailed information on how to contribute, see docs/CONTRIBUTING.rst.

Rebuild Strategies

For detailed information on rebuild strategies, see docs/REBUILD_STRATEGIES.rst.

Supported build systems

Koji

Koji is the software that builds RPM packages from source tarballs and SPEC files. It uses its own Mock to create chroot environments to perform builds.

MBS comes with its own koji.conf config file which allows configuring for your custom Koji instance(s).

Mock

Mock is a simple program that will build source RPMs inside a chroot. It doesn't do anything terribly fancy other than populate a chroot with the contents specified by a configuration file, then build any input SRPM(s) in that chroot.

MBS is able to perform local module builds by directing local Mock.

MBS supports threaded Mock builds which utilizes performance and significantly speeds up local module builds.

Client tooling

mbs-manager

This command controls the MBS instance itself.

There are subcommands for running the MBS server, performing database migrations, generating certificates and submitting local module builds. For more info, there's an existing help available.

Client-side API

The MBS implements a RESTful interface for module build submission and state querying. Not all REST methods are supported. See below for details. For client tooling which utilizes the API, please refer to "Client tooling" section above.

Module build submission

Module submission is done via posting the modulemd SCM URL.

POST /module-build-service/1/module-builds/
{
    "scmurl": "https://src.fedoraproject.org/modules/foo?#f1d2d2f924e986ac86fdf7b36c94bcdf32beec15",
    "branch": "master"
}

If successful, the response will be the extended json representation of the new module entry. This json dictionary will include the module build ID in the "id" field.

HTTP 201 Created
{
    "id": 42,
    "state": 0,
    "state_name": "init",
    ...
}

Options:

  • buildrequire_overrides - the buildrequires to override the modulemd with. The overrides must be to existing buildrequires on the modulemd. The expected format is {'platform': ['f28', 'f29']}.
  • modulemd - a string for submitting a YAML modulemd file as a parameter in the JSON data as an alternative to sending it in a multipart/form-data request. Only allowed if scratch is True or if the MBS setting YAML_SUBMIT_ALLOWED is True.
  • module_name - a string to use as the module name if a scratch build is requested and the YAML modulemd is submitted using the modulemd parameter.
  • module_stream - a string to use as the stream name if a scratch build is requested and the YAML modulemd is submitted using the modulemd parameter.
  • rebuild_strategy - a string of the desired rebuild strategy (affects what components get rebuilt). For the available options, please look at the "Rebuild Strategies" section below.
  • require_overrides - the requires to override the modulemd with. The overrides must be to existing requires on the modulemd. The expected format is {'platform': ['f28', 'f29']}.
  • reuse_components_from - the ID or NSVC of the module build to reuse components from. If it's not set, MBS will try to find a compatible module build to reuse components from.
  • scratch - a boolean indicating if a scratch module build should be performed. Only allowed to be True if the MBS setting MODULES_ALLOW_SCRATCH is True.
  • side_tag - this string value instructs mbs to use a side tag for any required base modules. If a base module has koji_side_tag_format defined, then that format is evaluated with the value given here to determine the tag to use for that base module. If koji_side_tag_format is not defined for a base module, then this option has no effect.
  • srpms - an optional list of Koji upload URLs of SRPMs to include in a module scratch build. Only allowed if scratch is True.
  • yaml - a string of the input file when submitting a YAML modulemd file directly in a multipart/form-data request. Only allowed if scratch is True or if the MBS setting YAML_SUBMIT_ALLOWED is True. The basename of the file will be used as the module name.
  • rpm_component_ref_overrides - the commit refs to override the RPM component refs with. The expected format is {'rpm_component_name': "new_commit_ref"}.

Module build state query

Once created, the client can query the current build state by requesting the build task's URL.

GET /module-build-service/1/module-builds/1042

The response, if the task exists, would include various pieces of information about the referenced build task.

HTTP 200 OK
{
  "id": 1042,
  "koji_tag": "module-f8c7dcdcc884bf1d",
  "name": "cloud-init",
  "owner": "karsten",
  "scmurl": "https://src.fedoraproject.org/modules/cloud-init?#d5fc9ab58f359b618e67ebdd0c7b143962242546",
  "state": 5,
  "state_name": "ready",
  "state_reason": null,
  "stream": "master",
  "tasks": {
    "rpms": {
      "cloud-init": {
        "nvr": "cloud-init-0.7.9-9.module_f8c7dcdc",
        "state": 1,
        "state_reason": "",
        "task_id": 22264880
      },
      "module-build-macros": {
        "nvr": "module-build-macros-0.1-1.module_f8c7dcdc",
        "state": 1,
        "state_reason": "",
        "task_id": 22264426
      },
      "pyserial": {
        "nvr": "pyserial-3.1.1-5.module_f8c7dcdc",
        "state": 1,
        "state_reason": "",
        "task_id": 22264727
      },
      ...
    }
  },
  "time_completed": "2017-10-05T11:58:44Z",
  "time_modified": "2017-10-05T11:58:58Z",
  "time_submitted": "2017-10-05T11:37:39Z",
  "version": "20171005113458"
}

The response includes:

  • id - the ID of the module build.
  • koji_tag - the Koji tag the component builds are tagged in.
  • name - the name of the module.
  • owner - the username of the owner or person who submitted the module build.
  • scmurl - the source control URL used to build the module.
  • state - the numerical state of the module build.
  • state_name - the named state of the module build. See the section called "Module Build States" for more information.
  • state_reason - the reason why the module build is in this state. This is useful when the build fails.
  • stream - the module's stream.
  • tasks - a dictionary of information about the individual component builds.
  • time_completed - Zulu ISO 8601 timestamp of when the module build completed.
  • time_modified - Zulu ISO 8601 timestamp of when the module build was last modified.
  • time_submitted - Zulu ISO 8601 timestamp of when the module build was submitted.
  • version - the module build's version.

Listing all module builds

The list of all tracked builds and their states can be obtained by querying the "module-builds" resource. There are a number of configurable GET parameters to change how the module builds are displayed. These parameters are:

  • verbose - Shows the builds with additional detail such as the modulemd and state trace (i.e. verbose=True). This value defaults to False.
  • short - Shows the builds with a minimum amount of information (i.e. short=True). This value defaults to False.
  • page - Specifies which page should be displayed (e.g. page=3). This value defaults to 1.
  • per_page - Specifies how many items per page should be displayed (e.g. per_page=20). This value defaults to 10.
  • order_by - a database column to order the API by in ascending order. Multiple can be provided.
  • order_desc_by - a database column to order the API by in descending order. Multiple can be provided. This defaults to id.

An example of querying the "module-builds" resource with the "per_page" and the "page" parameters:

GET /module-build-service/1/module-builds/?per_page=2&page=1
HTTP 200 OK
{
  "items": [
    {
      "id": 124,
      "koji_tag": "module-de66baf89b40367c",
      "name": "testmodule",
      "owner": "mprahl",
      "scmurl": "https://src.fedoraproject.org/modules/testmodule.git?#86d9cfe53d20118d863ae051641fc3784d91d981",
      "state": 5,
      "state_name": "ready",
      "state_reason": null,
      "stream": "master",
      "tasks": {
        "rpms": {
          "ed": {
            "nvr": "ed-1.14.1-4.module_d2a2f5c8",
            "state": 1,
            "state_reason": "Reused component from previous module build",
            "task_id": 22267993
          },
          "mksh": {
            "nvr": "mksh-56b-1.module_d2a2f5c8",
            "state": 1,
            "state_reason": "Reused component from previous module build",
            "task_id": 22268059
          }
        }
      },
      "time_completed": "2017-10-05T18:45:56Z",
      "time_modified": "2017-10-05T18:46:10Z",
      "time_submitted": "2017-10-05T18:34:39Z",
      "version": "20171005183359"
    },
    {
      "id": 123,
      "koji_tag": "module-4620ad476f3d2b5c",
      "name": "testmodule",
      "owner": "mprahl",
      "scmurl": "https://src.fedoraproject.org/modules/testmodule.git?#373bb6eccccbfebbcb222a2723e643e7095c7973",
      "state": 5,
      "state_name": "ready",
      "state_reason": null,
      "stream": "master",
      "tasks": {
        "rpms": {
          "ed": {
            "nvr": "ed-1.14.1-4.module_d2a2f5c8",
            "state": 1,
            "state_reason": "Reused component from previous module build",
            "task_id": 22267993
          },
          "mksh": {
            "nvr": "mksh-56b-1.module_d2a2f5c8",
            "state": 1,
            "state_reason": "Reused component from previous module build",
            "task_id": 22268059
          }
        }
      },
      "time_completed": "2017-10-05T18:45:50Z",
      "time_modified": "2017-10-05T18:46:01Z",
      "time_submitted": "2017-10-05T18:24:09Z",
      "version": "20171005182359"
    }
  ],
  "meta": {
    "first": "http://mbs.fedoraproject.org/module-build-service/1/module-builds/?per_page=2&page=1",
    "last": "http://mbs.fedoraproject.org/module-build-service/1/module-builds/?per_page=2&page=340",
    "next": "http://mbs.fedoraproject.org/module-build-service/1/module-builds/?per_page=2&page=2",
    "page": 1,
    "pages": 60,
    "per_page": 2,
    "prev": null,
    "total": 120
  }
}

An example of querying the "module-builds" resource with the "verbose", "per_page", and the "page" parameters:

GET /module-build-service/1/module-builds/?per_page=2&page=1?verbose=true
HTTP 200 OK
{
  "items": [
    {
      "base_module_buildrequires": [
        {
          "context": "00000000",
          "name": "platform",
          "stream": "f29",
          "stream_version": 290000,
          "version": "5"
        }
      ],
      "component_builds": [
        57047,
        57048
      ],
      "id": 124,
      "koji_tag": "module-de66baf89b40367c",
      "modulemd": "...."
      "name": "testmodule",
      "owner": "mprahl",
      "reused_module_id": 121,
      "scmurl": "https://src.fedoraproject.org/modules/testmodule.git?#86d9cfe53d20118d863ae051641fc3784d91d981",
      "state": 5,
      "state_name": "ready",
      "state_reason": null,
      "state_trace": [
        {
          "reason": null,
          "state": 1,
          "state_name": "wait",
          "time": "2017-10-05T18:34:50Z"
        },
        ...
      ],
      "state_url": "/module-build-service/1/module-builds/1053",
      "stream": "master",
      "tasks": {
        "rpms": {
          "ed": {
            "nvr": "ed-1.14.1-4.module_d2a2f5c8",
            "state": 1,
            "state_reason": "Reused component from previous module build",
            "task_id": 22267993
          },
          "mksh": {
            "nvr": "mksh-56b-1.module_d2a2f5c8",
            "state": 1,
            "state_reason": "Reused component from previous module build",
            "task_id": 22268059
          }
        }
      },
      "time_completed": "2017-10-05T18:45:56Z",
      "time_modified": "2017-10-05T18:46:10Z",
      "time_submitted": "2017-10-05T18:34:39Z",
      "version": "20171005183359"
    },
    {
      "component_builds": [
        57045,
        57046
      ],
      "id": 123,
      "koji_tag": "module-4620ad476f3d2b5c",
      "modulemd": "...."
      "name": "testmodule",
      "owner": "mprahl",
      "scmurl": "https://src.fedoraproject.org/modules/testmodule.git?#373bb6eccccbfebbcb222a2723e643e7095c7973",
      "state": 5,
      "state_name": "ready",
      "state_reason": null,
      "state_trace": [
        {
          "reason": null,
          "state": 1,
          "state_name": "wait",
          "time": "2017-10-05T18:24:19Z"
        },
        ...
      ],
      "state_url": "/module-build-service/1/module-builds/1052",
      "stream": "master",
      "tasks": {
        "rpms": {
          "ed": {
            "nvr": "ed-1.14.1-4.module_d2a2f5c8",
            "state": 1,
            "state_reason": "Reused component from previous module build",
            "task_id": 22267993
          },
          "mksh": {
            "nvr": "mksh-56b-1.module_d2a2f5c8",
            "state": 1,
            "state_reason": "Reused component from previous module build",
            "task_id": 22268059
          }
        }
      },
      "time_completed": "2017-10-05T18:45:50Z",
      "time_modified": "2017-10-05T18:46:01Z",
      "time_submitted": "2017-10-05T18:24:09Z",
      "version": "20171005182359"
    }
  ],
  "meta": {
    "first": "http://mbs.fedoraproject.org/module-build-service/1/module-builds/?verbose=true&per_page=2&page=1",
    "last": "http://mbs.fedoraproject.org/module-build-service/1/module-builds/?verbose=true&per_page=2&page=340",
    "next": "http://mbs.fedoraproject.org/module-build-service/1/module-builds/?verbose=true&per_page=2&page=2",
    "page": 1,
    "pages": 120,
    "per_page": 2,
    "prev": null,
    "total": 60
  }
}

Filtering module builds

The module builds can be filtered by a variety of GET parameters. Some of these parameters include:

  • base_module_br - the name:stream:version:context of a base module the module buildrequires
  • base_module_br_context - the context of a base module the module buildrequires
  • base_module_br_name - the name of a base module the module buildrequires
  • base_module_br_stream - the stream of a base module the module buildrequires
  • base_module_br_stream_version - the stream version of a base module the module buildrequires
  • base_module_br_stream_version_lte - less than or equal to the stream version of a base module the module buildrequires
  • base_module_br_stream_version_gte - greater than or equal to the stream version of a base module the module buildrequires
  • base_module_br_version - the version of a base module the module buildrequires
  • batch
  • cg_build_koji_tag
  • completed_after - Zulu ISO 8601 format e.g. completed_after=2016-08-23T09:40:07Z
  • completed_before - Zulu ISO 8601 format e.g. completed_before=2016-08-22T09:40:07Z
  • koji_tag
  • modified_after - Zulu ISO 8601 format e.g. modified_after=2016-08-22T09:40:07Z
  • modified_before - Zulu ISO 8601 format e.g. modified_before=2016-08-23T09:40:07Z
  • name
  • new_repo_task_id
  • owner
  • rebuild_strategy
  • reuse_components_from - the compatible module that was used for component reuse
  • scmurl
  • state - Can be the state name or the state ID e.g. state=done. This parameter can be given multiple times, in which case or-ing will be used.
  • state_reason
  • stream
  • stream_version_lte - less than or equal to the stream version. This is limited to the major version. This value only applies to base modules.
  • submitted_after - Zulu ISO 8601 format e.g. submitted_after=2016-08-22T09:40:07Z
  • submitted_before - Zulu ISO 8601 format e.g. submitted_before=2016-08-23T09:40:07Z
  • version

An example of querying the "module-builds" resource with the "state", and the "submitted_before" parameters:

GET /module-build-service/1/module-builds/?state=done&submitted_before=2016-08-23T08:10:07Z
HTTP 200 OK
{
  "items": [
    {
      "id": 3,
      "state": 3,
      ...
    },
    {
      "id": 2,
      "state": 3,
      ...
    },
    {
      "id": 1,
      "state": 3,
      ...
    }
  ],
  "meta": {
    "first": "https://127.0.0.1:5000/module-build-service/1/module-builds/?per_page=10&page=1",
    "last": "https://127.0.0.1:5000/module-build-service/1/module-builds/?per_page=10&page=1",
    "page": 1,
    "pages": 1,
    "per_page": 3,
    "total": 3
  }

Component build state query

Getting particular component build is very similar to a module build query.

GET /module-build-service/1/component-builds/1

The response, if the build exists, would include various pieces of information about the referenced component build.

HTTP 200 OK
{
  "format": "rpms",
  "id": 854,
  "module_build": 42,
  "nvr": "pth-1-1",
  "package": "pth",
  "state": 1,
  "state_name": "COMPLETE",
  "state_reason": "",
  "task_id": 18367215
}

The response includes:

  • id - the ID of the component build.
  • format - typically "rpms".
  • nvr - the NVR of the component build.
  • package - the package name.
  • state - the numerical state of the component build.
  • state_name - the named component build state and can be "COMPLETE", "FAILED", or "CANCELED".
  • state_reason - the reason why the component build is in this state. This is useful when the build fails.
  • task_id - the related task ID in the backend buildsystem.

Listing component builds

An example of querying the "component-builds" resource without any additional parameters:

GET /module-build-service/1/component-builds/
HTTP 200 OK
{
  "items": [
    {
      "format": "rpms",
      "id": 854,
      "module_build": 42,
      "package": "pth",
      "state": 1,
      "state_name": "COMPLETE",
      "state_reason": "",
      "state_trace": [
        {
          "reason": "Submitted pth to Koji",
          "state": 0,
          "state_name": "init",
          "time": "2017-03-14T00:07:43Z"
        },
        {
          "reason": "",
          "state": 1,
          "state_name": "wait",
          "time": "2017-03-14T00:13:30Z"
        },
        {
          "reason": "",
          "state": 1,
          "state_name": "wait",
          "time": "2017-03-14T14:41:21Z"
        }
      ],
      "task_id": 18367215
    },
    ...
  ],
  "meta": {
    "first": "http://mbs.fedoraproject.org/module-build-service/1/component-builds/?per_page=10&page=1",
    "last": "http://mbs.fedoraproject.org/module-build-service/1/component-builds/?per_page=10&page=5604",
    "next": "http://mbs.fedoraproject.org/module-build-service/1/component-builds/?per_page=10&page=2",
    "page": 1,
    "pages": 5604,
    "per_page": 10,
    "prev": null,
    "total": 56033
  }
}

Filtering component builds

The component builds can be filtered by a variety of GET parameters. Some of these parameters include:

  • batch
  • build_time_only - boolean e.g. "true" or "false"
  • format
  • module_id or module_build
  • nvr
  • package
  • ref
  • scmurl
  • state - Can be the state name or the state ID. Koji states are used for resolving to IDs. This parameter can be given multiple times, in which case or-ing will be used.
  • state_reason
  • tagged - boolean e.g. "true" or "false"
  • tagged_in_final - boolean e.g. "true" or "false"
  • task_id

Import module

Importing of modules is done via posting the SCM URL of a repository which contains the generated modulemd YAML file. Name, stream, version, context and other important information must be present in the metadata.

POST /module-build-service/1/import-module/
{
  "scmurl": "https://src.fedoraproject.org/modules/foo.git?#21f92fb05572d81d78fd9a27d313942d45055840"
}

If the module build is imported successfully, JSON containing the most important information is returned from MBS. The JSON also contains log messages collected during the import.

HTTP 201 Created
{
  "module": {
    "component_builds": [],
    "context": "00000000",
    "id": 3,
    "koji_tag": "",
    "name": "mariadb",
    "owner": "mbs_import",
    "rebuild_strategy": "all",
    "scmurl": null,
    "siblings": [],
    "state": 5,
    "state_name": "ready",
    "state_reason": null,
    "stream": "10.2",
    "time_completed": "2018-07-24T12:58:14Z",
    "time_modified": "2018-07-24T12:58:14Z",
    "time_submitted": "2018-07-24T12:58:14Z",
    "version": "20180724000000"
  },
  "messages": [
    "Updating existing module build mariadb:10.2:20180724000000:00000000.",
    "Module mariadb:10.2:20180724000000:00000000 imported"
  ]
}

If the module import fails, an error message is returned.

HTTP 422 Unprocessable Entity
{
  "error": "Unprocessable Entity",
  "message": "Incomplete NSVC: None:None:0:00000000"
}

Listing about

This API shows information about the MBS server:

GET /module-build-service/1/about/
HTTP 200 OK
{
  "auth_method": "oidc",
  "version": "1.3.26"
}

HTTP Response Codes

Possible response codes are for various requests include:

  • HTTP 200 OK - The task exists and the query was successful.
  • HTTP 201 Created - The module build task was successfully created.
  • HTTP 400 Bad Request - The client's input isn't a valid request.
  • HTTP 401 Unauthorized - No 'authorization' header found.
  • HTTP 403 Forbidden - The SCM URL is not pointing to a whitelisted SCM server.
  • HTTP 404 Not Found - The requested URL has no handler associated with it or the requested resource doesn't exist.
  • HTTP 409 Conflict - The submitted module's NVR already exists.
  • HTTP 422 Unprocessable Entity - The submitted modulemd file is not valid or the module components cannot be retrieved
  • HTTP 500 Internal Server Error - An unknown error occured.
  • HTTP 501 Not Implemented - The requested URL is valid but the handler isn't implemented yet.
  • HTTP 503 Service Unavailable - The service is down, possibly for maintanance.

Module Build States

You can see the list of possible states with:

from module_build_service.common.models import BUILD_STATES
print(BUILD_STATES)

Here's a description of what each of them means:

init

This is (obviously) the first state a module build enters.

When a user first submits a module build, it enters this state. We parse the modulemd file, learn the NVR, and create a record for the module build.

Then, we validate that the components are available, and that we can fetch them. If this is all good, then we set the build to the 'wait' state. If anything goes wrong, we jump immediately to the 'failed' state.

wait

Here, the scheduler picks up tasks in wait and switches to build immediately. Eventually, we'll add throttling logic here so we don't submit too many builds for the build system to handle.

build

The scheduler works on builds in this state. We prepare the buildroot, submit builds for all the components, and wait for the results to come back.

done

Once all components have succeeded, we set the top-level module build to 'done'.

failed

If any of the component builds fail, then we set the top-level module build to 'failed' also.

ready

This is a state to be set when a module is ready to be part of a larger compose. perhaps it is set by an external service that knows about the Grand Plan.

Bus messages

Supported messaging backends:

  • fedmsg - Federated Messaging with ZeroMQ
  • in_memory - Local/internal messaging only
  • amq - Apache ActiveMQ

Message Topic

The suffix for message topics concerning changes in module state is module.state.change. Currently, it is expected that these messages are sent from koji or module_build_service_daemon, i.e. the topic is prefixed with *.buildsys. or *.module_build_service., respectively.

Message Body

The message body is a dictionary with these fields:

state

This is the current state of the module, corresponding with the states described above in "Module Build States".

name, version, release

Name, version and release of the module.

scmurl

Specifies the exact repository state from which a module is built.

E.g. "scmurl": "https://src.stg.fedoraproject.org/modules/testmodule.git?#020ea37251df5019fde9e7899d2f7d7a987dfbf5"

topdir

The toplevel directory containing the trees for each architecture of a module. This field is only present when a module finished building, i.e. with the states 'done' or 'ready'.

Configuration

MBS configures itself according to the environment where it runs + according to the following rules (all of them are evaluated from top to bottom):

  • DevConfiguration is the initial configuration chosen.

  • If configuration file is found within its final installation location, ProdConfiguration is assumed.

  • If Flask app running within mod_wsgi is detected, ProdConfiguration is assumed.

  • If environment variables determining configuration file/section are found, they are used for configuration. Following environment variables are recognized:

    • MBS_CONFIG_FILE: Overrides default configuration file location, typically /etc/module-build-service/config.py. If set to the empty string, no configuration file will be read and default values will be used.
    • MBS_CONFIG_SECTION: Overrides configuration section.

    It is possible to set these values in httpd using SetEnv, anywhere in /etc/profile.d/ etc.

  • If test-runtime environment is detected, TestConfiguration is used, otherwise...

  • if MODULE_BUILD_SERVICE_DEVELOPER_ENV is set to some reasonable value, DevConfiguration is forced and config.py is used directly from the MBS's develop instance. For more information see docs/CONTRIBUTING.rst.

Setting Up Kerberos + LDAP Authentication

MBS defaults to using OIDC as its authentication mechanism. It additionally supports Kerberos (through mod_auth_gssapi) + LDAP, where Kerberos proves the user's identity and LDAP is used to determine the user's group membership. To configure this, the following must be set in /etc/module-build-service/config.py:

  • AUTH_METHOD must be set to 'kerberos'.
  • LDAP_URI is the URI to connect to LDAP (e.g. 'ldaps://ldap.domain.local:636' or 'ldap://ldap.domain.local').
  • LDAP_GROUPS_DN is the distinguished name of the container or organizational unit where groups are located (e.g. 'ou=groups,dc=domain,dc=local'). MBS does not search the tree below the distinguished name specified here for security reasons because it ensures common names are unique.
  • ALLOWED_GROUPS and ADMIN_GROUPS both need to declare the common name of the LDAP groups, not the distinguished name.

Development

For help on setting up a development environment, see docs/CONTRIBUTING.rst.

License

MBS is licensed under MIT license. See LICENSE file for details.

Parts of MBS are licensed under 3-clause BSD license from: https://github.com/projectatomic/atomic-reactor/blob/master/LICENSE

Virtual Modules

For a detailed description of virtual modules, see docs/VIRTUAL_MODULES.rst.