Code Contribution Guide

Code Contribution Guide

This document provides some necessary points for developers to consider when writing and reviewing Ironic code. The checklist will help developers get things right.

Getting Started

If you’re completely new to OpenStack and want to contribute to the ironic project, please start by familiarizing yourself with the Infra Team’s Developer Guide. This will help you get your accounts set up in Launchpad and Gerrit, familiarize you with the workflow for the OpenStack continuous integration and testing systems, and help you with your first commit.

LaunchPad Project

Most of the tools used for OpenStack require a launchpad.net ID for authentication.

Adding New Features

Starting with the Mitaka development cycle, Ironic tracks new features using RFEs (Requests for Feature Enhancements) instead of blueprints. These are bugs with ‘rfe’ tag, and they should be submitted before a spec or code is proposed. When a member of ironic-drivers launchpad team decides that the proposal is worth implementing, a spec (if needed) and code should be submitted, referencing the RFE bug. Contributors are welcome to submit a spec and/or code before the RFE is approved, however those patches will not land until the RFE is approved.

Feature Submission Process

  1. Submit a bug report at https://bugs.launchpad.net/ironic/+filebug. There are two fields that must be filled: ‘summary’ and ‘further information’. The ‘summary’ must be brief enough to fit in one line: if you can’t describe it in a few words it may mean that you are either trying to capture more than one RFE at once, or that you are having a hard time defining what you are trying to solve at all.
  2. Describe the proposed change in the ‘further information’ field. The description should provide enough details for a knowledgeable developer to understand what is the existing problem in the current platform that needs to be addressed, or what is the enhancement that would make the platform more capable, both from a functional and a non-functional standpoint.
  3. Submit the bug, add an ‘rfe’ tag to it and assign yourself or whoever is going to work on this feature.
  4. As soon as a member of the ironic-drivers team acknowledges the bug, it will be moved into the ‘Triaged’ state. The importance will be set to ‘Wishlist’ to signal the fact that the report is indeed a feature and there is no severity associated to it. Discussion about the RFE, and whether to approve it, happens in bug comments while in the ‘Triaged’ state.
  5. The ironic-drivers team will evaluate the RFE and may advise the submitter to file a spec in ironic-specs to elaborate on the feature request, in case the RFE requires extra scrutiny, more design discussion, etc. For the spec submission process, please see the Ironic Specs Process.
  6. If a spec is not required, once the discussion has happened and there is positive consensus among the ironic-drivers team on the RFE, the RFE is ‘approved’, and its tag will move from ‘rfe’ to ‘rfe-approved’. This means that the feature is approved and the related code may be merged.
  7. If a spec is required, the spec must be submitted (with the bug properly referenced as ‘Partial-Bug’ in the commit message), reviewed, and merged before the RFE will be ‘approved’ (and the tag changed to ‘rfe-approved’).
  8. The bug then goes through the usual process – first to ‘In progress’ when the spec/code is being worked on, then ‘Fix Released’ when it is implemented.
  9. If the RFE is rejected, the ironic-drivers team will move the bug to “Won’t Fix” status.

Change Tracking

When working on an RFE, please be sure to tag your commits properly: “Partial-Bug: #xxxx” or “Related-Bug: #xxxx” for intermediate commits for the feature, and “Closes-Bug: #xxxx” for the final commit. It is also helpful to set a consistent review topic, such as “bug/xxxx” for all patches related to the RFE.

If the RFE spans across several projects (e.g. ironic and python-ironicclient), but the main work is going to happen within ironic, please use the same bug for all the code you’re submitting, there is no need to create a separate RFE in every project.

Note

Currently the Ironic bug tracker is managed by the open ‘ironic-bugs’ team, not the ironic-drivers team. This means that anyone may edit bug details, and there is room to game the system here. RFEs may only be approved by members of the ironic-drivers team.

Managing Change Sets

If you would like some help, or if you (or some members of your team) are unable to continue working on the feature, updating and maintaining the changes, please let the rest of the ironic community know. You could leave a comment in one or more of the changes/patches, bring it up in IRC, the weekly meeting, or on the OpenStack development email list. Communicating this will make other contributors aware of the situation and allow for others to step forward and volunteer to continue with the work.

In the event that a contributor leaves the community, do not expect the contributor’s changes to be continued unless someone volunteers to do so.

Timeline Expectations

As with any large project, it does take time for features and changes to be merged in any of the project repositories. This is largely due to limited review bandwidth coupled with varying reviewer priorities and focuses.

When establishing an understanding of complexity, the following things should be kept in mind.

  • Generally, small and minor changes can gain consensus and merge fairly quickly. These sorts of changes would be: bug fixes, minor documentation updates, follow-up changes.
  • Medium changes generally consist of driver feature parity changes, where one driver is working to match functionality of another driver.
    • These changes generally only require an RFE for the purposes of tracking and correlating the change.
    • Documentation updates are expected to be submitted with or immediately following the initial change set.
  • Larger or controversial changes generally take much longer to merge. This is often due to the necessity of reviewers to gain additional context and for change sets to be iterated upon to reach a state where there is consensus. These sorts of changes include: database, object, internal interface additions, RPC, rest API changes.
    • These changes will very often require specifications to reach consensus, unless there are pre-existing patterns or code already present.
    • These changes may require many reviews and iterations, and can also expect to be impacted by merge conflicts as other code or features are merged.
    • These changes must typically be split into a series of changes. Reviewers typically shy away from larger single change sets due to increased difficulty in reviewing.
    • Do not expect any API or user-visible data model changes to merge after the API client freeze. Some substrate changes may merge if not user visible.
  • You should expect complex features, such as cross-project features or integration, to take longer than a single development cycle to land.
    • Building consensus is vital.
    • Often these changes are controversial or have multiple considerations that need to be worked through in the specification process, which may cause the design to change. As such, it may take months to reach consensus over design.
    • These features are best broken into larger chunks and tackled in an incremental fashion.

Driver Internal Info

The driver_internal_info node field was introduced in the Kilo release. It allows driver developers to store internal information that can not be modified by end users. Here is the list of existing common and agent driver attributes:

  • Common attributes:
    • is_whole_disk_image: A Boolean value to indicate whether the user image contains ramdisk/kernel.
    • clean_steps: An ordered list of clean steps that will be performed on the node.
    • instance: A list of dictionaries containing the disk layout values.
    • root_uuid_or_disk_id: A String value of the bare metal node’s root partition uuid or disk id.
    • persistent_boot_device: A String value of device from ironic.common.boot_devices.
    • is_next_boot_persistent: A Boolean value to indicate whether the next boot device is persistent_boot_device.
  • Agent driver attributes:
    • agent_url: A String value of IPA API URL so that Ironic can talk to IPA ramdisk.
    • hardware_manager_version: A String value of the version of the hardware manager in IPA ramdisk.
    • target_raid_config: A Dictionary containing the target RAID configuration. This is a copy of the same name attribute in Node object. But this one is never actually saved into DB and is only read by IPA ramdisk.

Note

These are only some fields in use. Other vendor drivers might expose more driver_internal_info properties, please check their development documentation and/or module docstring for details. It is important for developers to make sure these properties follow the precedent of prefixing their variable names with a specific interface name (e.g., ilo_bar, drac_xyz), so as to minimize or avoid any conflicts between interfaces.

Ironic Specs Process

Specifications must follow the template which can be found at specs/template.rst, which is quite self-documenting. Specifications are proposed by adding them to the specs/approved directory, adding a soft link to it from the specs/not-implemented directory, and posting it for review to Gerrit. For more information, please see the README.

The same Gerrit process as with source code, using the repository ironic-specs, is used to add new specifications.

All approved specifications are available at: https://specs.openstack.org/openstack/ironic-specs. If a specification has been approved but not completed within one or more releases since the approval, it may be re-reviewed to make sure it still makes sense as written.

Ironic specifications are part of the RFE (Requests for Feature Enhancements) process. You are welcome to submit patches associated with an RFE, but they will have a -2 (“do not merge”) until the specification has been approved. This is to ensure that the patches don’t get accidentally merged beforehand. You will still be able to get reviewer feedback and push new patch sets, even with a -2. The list of core reviewers for the specifications is small but mighty. (This is not necessarily the same list of core reviewers for code patches.)

Changes to existing specs

For approved but not-completed specs:

  • cosmetic cleanup, fixing errors, and changing the definition of a feature can be done to the spec.

For approved and completed specs:

  • changing a previously approved and completed spec should only be done for cosmetic cleanup or fixing errors.
  • changing the definition of the feature should be done in a new spec.

Please see the Ironic specs process wiki page for further reference.

Creative Commons Attribution 3.0 License

Except where otherwise noted, this document is licensed under Creative Commons Attribution 3.0 License. See all OpenStack Legal Documents.