Contributor Documentation

Contributing to nova gives you the power to help add features, fix bugs, enhance documentation, and increase testing. Contributions of any type are valuable, and part of what keeps the project going. Here are a list of resources to get your started.

Basic Information

• So You Want to Contribute…
  • Communication
  • Contacting the Core Team
  • New Feature Planning
  • Task Tracking
  • Reporting a Bug
  • Getting Your Patch Merged
  • Project Team Lead Duties

Getting Started

• How to get (more) involved with Nova: Overview of engaging in the project

• Development Quickstart: Get your computer setup to contribute

• Repo Overview: Terse map of the Nova repository layout, package structure, and documentation sections.

• Agentic Coding: Conventions for AI-assisted development, including the AGENTS.md routing layer and local scratch files.

Nova Process

The nova community is a large community. We have lots of users, and they all have a lot of expectations around upgrade and backwards compatibility. For example, having a good stable API, with discoverable versions and capabilities is important for maintaining the strong ecosystem around nova.

Our process is always evolving, just as nova and the community around nova evolves over time. If there are things that seem strange, or you have ideas on how to improve things, please bring them forward on IRC or the openstack-discuss mailing list, so we continue to improve how the nova community operates.

This section looks at the processes and why. The main aim behind all the process is to aid communication between all members of the nova community, while keeping users happy and keeping developers productive.

• Scope of the Nova project: The focus is on features and bug fixes that make nova work better within this scope

• Development policies: General guidelines about what’s supported

• Nova team process: The processes we follow around feature and bug submission, including how the release calendar works, and the freezes we go under

• Blueprints, Specs and Priorities: An overview of our tracking artifacts.

• Chronological PTL guide: A chronological PTL reference guide

Code Conventions

• OpenStack code and documentation guide: General OpenStack contributor conventions covering style, testing, and documentation standards.

• Nova HACKING.rst: Nova-specific style rules and N-check descriptions; enforced by tox -e pep8.

• Dependencies: Where to declare Python, documentation, and system package dependencies.

• Commit Messages: Nova commit message guidance, including Gerrit footers, DCO sign-off, and AI attribution trailers.

• Release Notes: When we need a release note for a contribution.

• Internationalization: What we require for i18n in patches.

• Database migrations: How to write schema and data migrations when adding a feature or bugfix.

• Upgrade checks: How to write automated upgrade checks when adding a feature or bugfix.

Reviewing

• Code Review Guide for Nova: Important cheat sheet for what’s important when doing code review in Nova, especially some things that are hard to test for, but need human eyes.

• Documentation Guidelines: Guidelines for handling documentation contributions

Testing

Because Python is a dynamic language, code that is not tested might not even be Python code. All new code needs to be validated somehow.

• Test Strategy: An overview of our test taxonomy and the kinds of testing we do and expect.

• Testing Guides: There are also specific testing guides for features that are hard to test in our gate.

  • Testing NUMA related hardware setup with libvirt

  • Testing Serial Console

  • Testing Zero Downtime Upgrade Process

  • Testing Down Cells

  • Testing PCI passthrough and SR-IOV with emulated PCI NIC

• Profiling Guides: These are guides to profiling nova.

  • Profiling With Eventlet

The Nova API

Because we have many consumers of our API, we’re extremely careful about changes done to the API, as the impact can be very wide.

• Extending the API: How the code is structured inside the API layer

• API Microversions: How the API is (micro)versioned and what you need to do when adding an API exposed feature that needs a new microversion.

• API reference guideline: The guideline to write the API reference.

Nova also provides notifications over the RPC API, which you may wish to extend.

• Notifications: How to add your own notifications

Nova Major Subsystems

Major subsystems in nova have different needs. If you are contributing to one of these please read the reference guide before diving in.

• Move operations

  • Evacuate vs Rebuild: Describes the differences between the often-confused evacuate and rebuild operations.

  • Resize and cold migrate: Describes the differences and similarities between resize and cold migrate operations.