Development Guide
This section provides guidance on code changes, version control, and releases.
Git
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Release Manager Guide
This document describes the process to release Apache Ozone. The process is not yet scripted, and the documentation is a work in progress.
Code References
This page lists references that help you read and navigate the Apache
Ozone Enhancement Proposals
This document proposes a standard process for creating, reviewing, publishing, and maintaining design proposals for the Apache Ozone project.
Upgrade Compatibility
Zero Downtime Upgrade (ZDU) lets the internal components of an Ozone cluster (OM, SCM, Datanode, S3 Gateway, and Recon) run in mixed versions during an upgrade with no interruption to service. Additionally, Ozone provides a window where a cluster can be downgraded after the upgrade. Both of these features require every release to uphold certain compatibility guarantees; otherwise, an upgrade can silently introduce problems such as diverging OM state machines, a corrupted container replica, or a Datanode that is unable to re-register. This page is a practical guide to what counts as an incompatible change inside the cluster, and how to safely introduce such changes in each area of the code.