Release Plan 2.4.0 (Oct 2019)

Release Dates

• KIP Freeze: Sep 25, 2019 (a KIP must be accepted by this date in order to be considered for this release)
• Feature Freeze: Oct 4, 2019 (major features merged & working on stabilization, minor features have PR, release branch cut; anything not in this state will be automatically moved to the next release in JIRA)
• Code Freeze: Oct 16, 2019
• Release: Dec 16

These dates are goals and subject to change, but we expect to stay on the Time Based Release Plan unless unexpected critical issues come up. While the target release date is fixed at ~2w after code freeze, RCs will roll out as needed until the release vote passes.

The release manager is Manikumar Reddy O.

Release Features

This is a list of all the features/improvements/bugfixes that we can include with release notes:

- KIP-213: Support non-key joining in KTable
- KIP-307: Allow to define custom processor names with KStreams DSL
- KIP-309: Add toUpperCase support to sasl.kerberos.principal.to.local rule
- KIP-369: Alternative Partitioner to Support "Always Round-Robin" Selection
- KIP-379: Multiple Consumer Group Management
- KIP-382: MirrorMaker 2.0
- KIP-392: Allow consumers to fetch from closest replica
- KIP-412: Extend Admin API to support dynamic application log levels
- KIP-429: Kafka Consumer Incremental Rebalance Protocol (Partially implemented)
- KIP-434: Add Replica Fetcher and Log Cleaner Count Metrics
- KIP-440: Extend Connect Converter to support headers

- KIP-444: Augment metrics for Kafka Stream (Partially Implemented)
- KIP-455: Admin API for Replica Reassignment (Partially implemented)
- KIP-460: Admin Leader Election RPC
- KIP-464: Defaults for AdminClient#createTopic

- KIP-467: Augment ProduceResponse error messaging for specific culprit records (Partially implemented)
- KIP-470: TopologyTestDriver test input and output usability improvements
- KIP-471: Expose RocksDB Metrics in Kafka Streams (Partially Implemented)
- KIP-474: To deprecate WindowStore#put(key, value)
- KIP-475: New Metrics to Measure Number of Tasks on a Connector
- KIP-479: Add StreamJoined config object to Join
- KIP-480: Sticky Partitioner
- KIP-481: SerDe Improvements for Connect Decimal type in JSON
- KIP-482: The Kafka Protocol should Support Optional Fields
- KIP-484: Expose metrics for group and transaction metadata loading duration
- KIP-488: Clean up Sum,Count,Total Metrics
- KIP-492: Add java security providers in Kafka Security config
- KIP-495: Dynamically Adjust Log Levels in Connect
- KIP-496: Administrative API to delete consumer offsets
- KIP-503: Add metric for number of topics marked for deletion
- KIP-504: Add new Java Authorizer Interface
- KIP-525: Return topic metadata and configs in CreateTopics response
- KIP-507: Securing Internal Connect REST Endpoints

- KIP-511: Collect and Expose Client's Name and Version in the Brokers (Partially implemented)

- KIP-517: Add consumer metrics to observe user poll behavior
- KIP-521: Enable redirection of Connect's log4j messages to a file by default
- KIP-528: Deprecate PartitionGrouper configuration and interface

How to Contribute

Before code freeze:

• Participate in votes and discussions to land or postpone the open KIPs.
• Review patches. We anticipate that this release will be bottlenecked mostly on reviews. The more reviewers, the more content we can fit in.
• Write unit/integration/system tests. We want to preserve the tradition of high-quality releases in Apache Kafka. 

After code freeze:

• Write more unit/integration/system tests. We want to preserve the tradition of high-quality releases in Apache Kafka.
• Improve documentation
• Test the release candidates
• Open blocker JIRAs on critical issues found. Open non-blocker JIRAs on any other issues found.
• Fix critical bugs
• Review bug fixes
• Vote on RCs. Even though only PMC votes are binding, community votes are super important as we evaluate the readiness of the release

Open Issues

Also feel free to refer to this release page for more details of the included tickets.

Planned KIP Content

Note: The planned content is not binding - final content will be based the features committed by branch-cutting date. See Kafka Improvement Proposals for the full list of KIPs.

Postponed to subsequent release