User:Mstone/Commentaries/Releases 3

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We make changes to our software for many reasons; however, we make scheduled (major) releases in order to deliver significant changes to our downstream partners. Major releases may include interface-breaking changes. They are different from unscheduled (minor) releases in that they contain larger and more thoroughly planned changes.

Process Overview

Scheduled software releases consist of four phases:

1. OBJECTIVES: Choose a target month. Solicit goals and priorities for the release. Propose ends and means.
2. DEVELOPMENT: Generate changes which may help to meet the new goals.
3. RELEASE: Generate and execute a release contract for each desired change. Execute the Software ECO process to deliver the release.
4. DEPLOYMENT: Help downstream partners adapt to the new release.

Contracts

release contract

an agreement between the release team and one or more contributors to attempt to integrate some desirable change into a release build.

release contracts normally describe:

1. the required quality of an acceptable change,
2. a test plan for judging the quality of a proposed change,
3. who will execute the test plan, and
4. the consequences of breaking the "contract".

(Typically, violation of a release contract will result in deferral of the proposed change.)

Process Step Details

OBJECTIVES

Write an Objectives page (e.g. 8.2.0) recording a consensus on:

• target month.
• development goals and priorities.
• lead customers.
• feasibility of proposed changes.

Module maintainers, product management, and the release team will be responsible for building and maintaining this consensus based on communal, customer, and institutional feedback. All three groups will be responsible for acting to achieve its mandates, e.g. as advisers, maintainers, and managers.

Schedule

We have learned that certain minimum amounts of time must be allocated to integration and testing. The following example schedule records some of this knowledge:

1. >60 days before target date Steam. Changes can be proposed at will and should be proposed as early as possible.
2. 60-30 days before target date Water. Proposals must pass muster with the release team. Release contracts should be written and integration should occur. This is feature-level change control.
3. 30 days before target date Ice. We branch for release and the release team produces release candidates as needed under package-level change-control. Developers should be focused on fixing bugs.
4. <15 days before target date Final Test. Get consensus from test, QA, and engineering communities, then finish the Release Process Checklist.
5. Release day. Announcement Day. Once Release checklist is complete, Kim sends announcement e-mail approving release for production.

DEVELOPMENT

Development consists of creating potentially releasable changes during a Steam period (no change control) and a Water period (feature-level change control).

Steam

Occurs: MORE than 60 days before target date

Prior to the transition to Water (feature-level change control), there is great freedom to propose changes because resources have not been allocated toward integrating and testing the proposed changes. We allocate these resources with release contracts.

Water

Occurs: 60-30 days before target date

When Steam transitions to Water, changes requiring reallocation of integration, test, or downstream resources (i.e. requiring a new release contract) will require approval by module maintainers and Release Management before being accepted. Minor changes can still be added without approval until the transition to Ice. Changes requiring great coordination to deliver like string changes and UI changes will be deferred if possible.

By the end of Water, developers are expected to have created release contracts for each desired change. See previous examples.

RELEASE

Release consists of integrating desirable changes created during development, then executing the Software ECO process to finalize the result.

Ice

Occurs: 30-0 days before target date

When Water transitions to Ice, the release team will branch the development stream twice creating updates and testing build streams.

• Both the updates and testing streams will be placed under package-level change control by the release team.
• The updates stream will be used to house packages being considered by the release team for insertion into the testing stream.
• Official QA will consider builds from the testing stream. When approved by official QA, these builds can become release candidates as part of the underlying Software ECO process being executed by the release team.

DEPLOYMENT

Upon completion of the Software ECO process, a new reference operating system is made available. However, further work must be done to adapt this component to the needs of downstream partners.