Neutron Core Reviewers

Neutron Core Reviewers

The Neutron Core Reviewer Team is responsible for many things related to Neutron. A lot of these things include mundane tasks such as the following:

  • Ensuring the bug count is low
  • Curating the gate and triaging failures
  • Working on integrating shared code from projects such as Oslo
  • Ensuring documentation is up to date and remains relevant
  • Ensuring the level of testing for Neutron is adequate and remains relevant as features are added
  • Helping new contributors with questions as they peel back the covers of Neutron
  • Answering questions and participating in mailing list discussions
  • Interfacing with other OpenStack teams and ensuring they are going in the same parallel direction
  • Reviewing and merging code into the neutron tree

In essence, core reviewers share the following common ideals:

  1. They share responsibility in the project’s success.
  2. They have made a long-term, recurring time investment to improve the project.
  3. They spend their time doing what needs to be done to ensure the projects success, not necessarily what is the most interesting or fun.

A core reviewer’s responsibility doesn’t end up with merging code. The above lists are adding context around these responsibilities.

Core Review Hierarchy

As Neutron has grown in complexity, it has become impossible for any one person to know enough to merge changes across the entire codebase. Areas of expertise have developed organically, and it is not uncommon for existing cores to defer to these experts when changes are proposed. Existing cores should be aware of the implications when they do merge changes outside the scope of their knowledge. It is with this in mind we propose a new system built around Lieutenants through a model of trust.

In order to scale development and responsibility in Neutron, we have adopted a Lieutenant system. The PTL is the leader of the Neutron project, and ultimately responsible for decisions made in the project. The PTL has designated Lieutenants in place to help run portions of the Neutron project. The Lieutenants are in charge of their own areas, and they can propose core reviewers for their areas as well. The core reviewer addition and removal polices are in place below. The Lieutenants for each system, while responsible for their area, ultimately report to the PTL. The PTL may opt to have regular one on one meetings with the lieutenants. The PTL will resolve disputes in the project that arise between areas of focus, core reviewers, and other projects. Please note Lieutenants should be leading their own area of focus, not doing all the work themselves.

As was mentioned in the previous section, a core’s responsibilities do not end with merging code. They are responsible for bug triage and gate issues among other things. Lieutenants have an increased responsibility to ensure gate and bug triage for their area of focus is under control.

The following are the current Neutron Lieutenants.

Area Lieutenant IRC nick
API Akihiro Motoki amotoki
DB Ann Taraday ataraday
Built-In Control Plane Kevin Benton kevinbenton
Client Akihiro Motoki amotoki
Abhishek Raut abhiraut
Docs Miguel Lavalle mlavalle
Infra Ihar Hrachyshka ihrachys
Armando Migliaccio armax
YAMAMOTO Takashi yamamoto
L3 Brian Haley haleyb
Miguel Lavalle mlavalle
Testing Jakub Libosvar jlibosva

Some notes on the above:

  • “Built-In Control Plane” means the L2 agents, DHCP agents, SGs, metadata agents and ML2.
  • The client includes commands installed server side.
  • L3 includes the L3 agent, DVR, Dynamic routing and IPAM.
  • Services includes FWaaS, LBaaS, and VPNaaS.
  • Note these areas may change as the project evolves due to code refactoring, new feature areas, and libification of certain pieces of code.
  • Infra means interactions with infra from a neutron perspective

Neutron also consists of several plugins, drivers, and agents that are developed effectively as sub-projects within Neutron in their own git repositories. Lieutenants are also named for these sub-projects to identify a clear point of contact and leader for that area. The Lieutenant is also responsible for updating the core review team for the sub-project’s repositories.

Area Lieutenant IRC nick
networking-bgpvpn networking-bagpipe Mathieu Rohon matrohon
Thomas Morin tmorin
net…-dynamic-routing Ryan Tidwell tidwellr
Vikram Choudhary vikram
neutron-fwaas Sridar Kandaswamy SridarK
networking-midonet Ryu Ishimoto ryu25
YAMAMOTO Takashi yamamoto
networking-odl Isaku Yamahata yamahata
networking-ovn Russell Bryant russellb
networking-sfc Cathy Zhang cathy

Existing Core Reviewers

Existing core reviewers have been reviewing code for a varying degree of cycles. With the new plan of Lieutenants and ownership, it’s fair to try to understand how they fit into the new model. Existing core reviewers seem to mostly focus in particular areas and are cognizant of their own strengths and weaknesses. These members may not be experts in all areas, but know their limits, and will not exceed those limits when reviewing changes outside their area of expertise. The model is built on trust, and when that trust is broken, responsibilities will be taken away.

Lieutenant Responsibilities

In the hierarchy of Neutron responsibilities, Lieutenants are expected to partake in the following additional activities compared to other core reviewers:

  • Ensuring feature requests for their areas have adequate testing and documentation coverage.
  • Gate triage and resolution. Lieutenants are expected to work to keep the Neutron gate running smoothly by triaging issues, filing elastic recheck queries, and closing gate bugs.
  • Triaging bugs for the specific areas.

Neutron Teams

Given all of the above, Neutron has a number of core reviewer teams with responsibility over the areas of code listed below:

Neutron Core Reviewer Team

Neutron core reviewers have merge rights to the following git repositories:

Please note that as we adopt to the system above with core specialty in particular areas, we expect this broad core team to shrink as people naturally evolve into an area of specialization.

Neutron Core Reviewer Teams for Plugins and Drivers

The plugin decomposition effort has led to having many drivers with code in separate repositories with their own core reviewer teams. For each one of these repositories in the following repository list, there is a core team associated with it:

These teams are also responsible for handling their own specs/RFEs/features if they choose to use them. However, by choosing to be a part of the Neutron project, they submit to oversight and veto by the Neutron PTL if any issues arise.

Neutron Specs Core Reviewer Team

Neutron specs core reviewers have +2 rights to the following git repositories:

The Neutron specs core reviewer team is responsible for reviewing specs targeted to all Neutron git repositories (Neutron + Advanced Services). It is worth noting that specs reviewers have the following attributes which are potentially different than code reviewers:

  • Broad understanding of cloud and networking technologies
  • Broad understanding of core OpenStack projects and technologies
  • An understanding of the effect approved specs have on the teams development capacity for each cycle

Specs core reviewers may match core members of the above mentioned groups, but the group can be extended to other individuals, if required.

Drivers Team

The drivers team is the group of people who have full rights to the specs repo. This team, which matches Launchpad Neutron Drivers team, is instituted to ensure a consistent architectural vision for the Neutron project, and to continue to disaggregate and share the responsibilities of the Neutron PTL. The team is in charge of reviewing and commenting on RFEs, and working with specification contributors to provide guidance on the process that govern contributions to the Neutron project as a whole. The team meets regularly to go over RFE’s and discuss the project roadmap. Anyone is welcome to join and/or read the meeting notes.

Release Team

The release team is a group of people with some additional gerrit permissions primarily aimed at allowing release management of Neutron sub-projects. These permissions include:

  • Ability to push signed tags to sub-projects whose releases are managed by the Neutron release team as opposed to the OpenStack release team.
  • Ability to push merge commits for Neutron or other sub-projects.
  • Ability to approve changes in all Neutron git repositories. This is required as the team needs to be able to quickly unblock things if needed, especially at release time.

Code Merge Responsibilities

While everyone is encouraged to review changes for these repositories, members of the Neutron core reviewer group have the ability to +2/-2 and +A changes to these repositories. This is an extra level of responsibility not to be taken lightly. Correctly merging code requires not only understanding the code itself, but also how the code affects things like documentation, testing, and interactions with other projects. It also means you pay attention to release milestones and understand if a patch you’re merging is marked for the release, especially critical during the feature freeze.

The bottom line here is merging code is a responsibility Neutron core reviewers have.

Adding or Removing Core Reviewers

A new Neutron core reviewer may be proposed at anytime on the openstack-dev mailing list. Typically, the Lieutenant for a given area will propose a new core reviewer for their specific area of coverage, though the Neutron PTL may propose new core reviewers as well. The proposal is typically made after discussions with existing core reviewers. Once a proposal has been made, three existing Neutron core reviewers from the Lieutenant’s area of focus must respond to the email with a +1. If the member is being added by a Lieutenant from an area of focus with less than three members, a simple majority will be used to determine if the vote is successful. Another Neutron core reviewer from the same area of focus can vote -1 to veto the proposed new core reviewer. The PTL will mediate all disputes for core reviewer additions.

The PTL may remove a Neutron core reviewer at any time. Typically when a member has decreased their involvement with the project through a drop in reviews and participation in general project development, the PTL will propose their removal and remove them. Please note there is no voting or vetoing of core reviewer removal. Members who have previously been a core reviewer may be fast-tracked back into a core reviewer role if their involvement picks back up and the existing core reviewers support their re-instatement.

Neutron Core Reviewer Membership Expectations

Neutron core reviewers have the following expectations:

  • Reasonable attendance at the weekly Neutron IRC meetings.
  • Participation in Neutron discussions on the mailing list, as well as
    in-channel in #openstack-neutron.
  • Participation in Neutron related design summit sessions at the OpenStack Summits.

Please note in-person attendance at design summits, mid-cycles, and other code sprints is not a requirement to be a Neutron core reviewer. The Neutron team will do its best to facilitate virtual attendance at all events. Travel is not to be taken lightly, and we realize the costs involved for those who partake in attending these events.

In addition to the above, code reviews are the most important requirement of Neutron core reviewers. Neutron follows the documented OpenStack code review guidelines. We encourage all people to review Neutron patches, but core reviewers are required to maintain a level of review numbers relatively close to other core reviewers. There are no hard statistics around code review numbers, but in general we use 30, 60, 90 and 180 day stats when examining review stats.

There are soft-touch items around being a Neutron core reviewer as well. Gaining trust with the existing Neutron core reviewers is important. Being able to work together with the existing Neutron core reviewer team is critical as well. Being a Neutron core reviewer means spending a significant amount of time with the existing Neutron core reviewers team on IRC, the mailing list, at Summits, and in reviews. Ensuring you participate and engage here is critical to becoming and remaining a core reviewer.

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