Neutron grew to become a big monolithic codebase, and its core team had a tough time making progress on a number of fronts, like adding new features, ensuring stability, etc. During the Kilo timeframe, a decomposition effort started, where the codebase got disaggregated into separate repos, like the high level services, and the various third-party solutions for L2 and L3 services, and the Stadium was officially born.
These initiatives enabled the various individual teams in charge of the smaller projects the opportunity to iterate faster and reduce the time to feature. This has been due to the increased autonomy and implicit trust model that made the lack of oversight of the PTL and the Neutron drivers/core team acceptable for a small number of initiatives. When the proposed arrangement allowed projects to be automatically enlisted as a Neutron project based simply on description, and desire for affiliation, the number of projects included in the Stadium started to grow rapidly, which created a number of challenges for the PTL and the drivers team.
In fact, it became harder and harder to ensure consistency in the APIs, architecture, design, implementation and testing of the overarching project; all aspects of software development, like documentation, integration, release management, maintenance, and upgrades started to being neglected for some projects and that led to some unhappy experiences.
The point about uniform APIs is particularly important, because the Neutron platform is so flexible that a project can take a totally different turn in the way it exposes functionality, that it is virtually impossible for the PTL and the drivers team to ensure that good API design principles are being followed over time. In a situation where each project is on its own, that might be acceptable, but allowing independent API evolution while still under the Neutron umbrella is counterproductive.
These challenges led the Neutron team to find a better balance between autonomy and consistency and lay down criteria that more clearly identify when a project can be eligible for inclusion in the Neutron governance.
This document describes these criteria, and document the steps involved to maintain the integrity of the Stadium, and how to ensure this integrity be maintained over time when modifications to the governance are required.
When is a project considered part of the Stadium?¶
In order to be considered part of the Stadium, a project must show a track record of alignment with the Neutron core project. This means showing proof of adoption of practices as led by the Neutron core team. Some of these practices are typically already followed by the most mature OpenStack projects:
Exhaustive OpenStack CI coverage: unit, functional, and tempest coverage using OpenStack CI (upstream) resources so that Grafana and OpenStack Health support is available. Access to CI resources and historical data by the team is key to ensuring stability and robustness of a project. In particular, it is of paramount importance to ensure that DB models/migrations are tested functionally to prevent data inconsistency issues or unexpected DB logic errors due to schema/models mismatch. For more details, please look at the following resources:
More Database related information can be found on:
Bear in mind that many projects have been transitioning their codebase and tests to fully support Python 3+, and it is important that each Stadium project supports Python 3+ the same way Neutron core does. For more information on how to do testing, please refer to the Neutron testing documentation.
Good release footprint, according to the chosen release model.
Adherence to deprecation and stable backports policies.
Client bindings and CLI developed according to the OpenStack Client plugin model.
On top of the above mentioned criteria, the following also are taken into consideration:
- A project must use, adopt and implement open software and technologies.
- A project must integrate with Neutron via one of the supported, advertised and maintained public Python APIs. REST API does not qualify (the project python-neutronclient is an exception).
- It adopts neutron-lib (with related hacking rules applied), and has proof of good decoupling from Neutron core internals.
- It provides an API that adopts API guidelines as set by the Neutron core team, and that relies on an open implementation.
- It adopts modular interfaces to provide networking services: this means that L2/7 services are provided in the form of ML2 mech drivers and service plugins respectively. A service plugin can expose a driver interface to support multiple backend technologies, and/or adopt the flavor framework as necessary.
Adding or removing projects to the Stadium¶
When a project is to be considered part of the Stadium, proof of compliance to the aforementioned practices will have to be demonstrated typically for at least two OpenStack releases. Application for inclusion is to be considered only within the first milestone of each OpenStack cycle, which is the time when the PTL and Neutron team do release planning, and have the most time available to discuss governance issues.
Projects part of the Neutron Stadium have typically the first milestone to get their house in order, during which time reassessment happens; if removed, because of substantial lack of meeting the criteria, a project cannot reapply within the same release cycle it has been evicted.
The process for proposing a repo into openstack/ and under the Neutron governance is to propose a patch to the openstack/governance repository. For example, to propose networking-foo, one would add the following entry under Neutron in reference/projects.yaml:
- repo: openstack/networking-foo tags: - name: release:independent
Typically this is a patch that the PTL, in collaboration with the project’s point of contact, will shepherd through the review process. This step is undertaken once it is clear that all criteria are met. The next section provides an informal checklist that shows what steps a project needs to go through in order to enable the PTL and the TC to vote positively on the proposed inclusion.
Once a project is included, it abides by the Neutron RFE submission process, where specifications to neutron-specs are required for major API as well as major architectural changes that may require core Neutron platform enhancements.
How to integrate documentation into docs.o.o: The documentation website has a section for project developer documentation. Each project in the Neutron Stadium must have an entry under the ‘Networking Sub Projects’ section that points to the developer documentation for the project, available at http://docs.openstack.org/developer/<your-project>/. This is a two step process that involves the following:
- Build the artefacts: this can be done by following example https://review.openstack.org/#/c/293399/.
- Publish the artefacts: this can be done by following example https://review.openstack.org/#/c/216448/.
More information can also be found on the project creator guide.
How to integrate into Grafana: Grafana is a great tool that provides the ability to display historical series, like failure rates of OpenStack CI jobs. A few examples that added dashboards over time are:
Any subproject must have a Grafana dashboard that shows failure rates for at least Gate and Check queues.
How to integrate into neutron-lib’s CI: there are a number of steps required to integrate with neutron-lib CI and adopt neutron-lib in general. One step is to validate that neutron-lib master is working with the master of a given project that uses neutron-lib. For example patch introduced such support for the Neutron project. Any subproject that wants to do the same would need to adopt the following few lines:
Line 1 and 2 respectively add a job to the periodic queue for the project, whereas line 3 introduced the failure rate trend for the periodic job to spot failure spikes etc. Make sure your project has the following:
How to port api-ref over to neutron-lib: to publish the subproject API reference into the Networking API guide you must contribute the API documentation into neutron-lib’s api-ref directory as done in the WADL/REST transition patch. Once this is done successfully, a link to the subproject API will show under the published table of content. An RFE bug tracking this effort effectively initiates the request for Stadium inclusion, where all the aspects as outlined in this documented are reviewed by the PTL.
How to port API definitions over the neutron-lib: the most basic steps to port API definitions over to neutron-lib are demonstrated in the following patches:
The neutron-lib patch introduces the elements that define the API, and testing coverage validates that the resource and actions maps use valid keywords. API reference documention is provided alongside the definition to keep everything in one place. The neutron patch uses the Neutron extension framework to plug the API definition on top of the Neutron API backbone. The change can only merge when there is a released version of neutron-lib.
How to integrate into the openstack release: every project in the Stadium must have release notes. In order to set up release notes, please see the patches below for an example on how to set up reno:
For release documentation related to Neutron, please check the Neutron policies document. Once, everything is set up and your project is released, make sure you see an entry on the release page (e.g. Newton. Make sure you release according to the project declared release model.
How to port OpenStack Client over to python-neutronclient: client API bindings and client command line interface support must be developed in python-neutronclient under osc module. If your project requires one or both, consider looking at the following example on how to contribute these two python-neutronclient according to the OSC framework and guidelines:
More information on how to develop python-openstackclient plugins can be found on the following links:
It is worth prefixing the commands being added with the keyword network to avoid potential clash with other commands with similar names. This is only required if the command object name is highly likely to have an ambiguous meaning.