RabbitMQ 3.12.0-beta.1

[michaelklishin]

RabbitMQ 3.12.0-beta.1

RabbitMQ 3.12.0-beta.1 is a preview of a new feature release.

Highlights

This release includes several new features and optimizations and graduates (makes mandatory) a number of feature flags.

The user-facing areas that have seen the biggest improvements in this release are

• Lower MQTT and Web MQTT memory footprint per connection
• Classic queue message store memory efficiency and footprint predictability
• OAuth 2, OIDC, IDP support

This release also features many internal API improvements in preparation to 4.0
with Khepri.

See Compatibility Notes below to learn about breaking or potentially breaking changes in this release.

Obtaining Packages

RabbitMQ releases are distributed via GitHub, Cloudsmith,
and PackageCloud.

Erlang/OTP Compatibility Notes

This release requires Erlang 25.0 or later.
This introduces feature parity for x86- and ARM64-based CPUs: Erlang 25 offers the JIT and
modern Flame Graph profiling tooling
for both of those major CPU architectures.

Provisioning Latest Erlang Releases explains
what package repositories and tools can be used to provision latest patch versions of Erlang 25.x.

Upgrading to 3.12

Documentation guides on upgrades

See the Upgrading guide for documentation on upgrades and RabbitMQ change log
for release notes of other releases.

Required Feature Flags

RabbitMQ 3.12.0 will require all feature flags from the 3.11.x release series to be enabled before upgrading,
similarly to how 3.11.0 required all feature flags introduced before 3.9.0.

If the feature flags are not enabled, RabbitMQ 3.12 and later nodes will refuse to start.

Mixed version cluster compatibility

RabbitMQ 3.12.0 nodes can run alongside 3.11.x nodes. 3.12.x-specific features can only be made available when all nodes in the cluster
upgrade to 3.12.0 or any other patch release in the new series.

While operating in mixed version mode, some aspects of the system may not behave as expected. The list of known behavior changes is covered below.
Once all nodes are upgraded to 3.12.0, these irregularities will go away.

Mixed version clusters are a mechanism that allows rolling upgrade and are not meant to be run for extended
periods of time (no more than a few hours).

Compatibility Notes

More Feature Flags Gratuate to Core Features ("Always Enabled")

RabbitMQ 3.12.0 will require all feature flags from the 3.11.x release series to be enabled before upgrading.

If the feature flags are not enabled, RabbitMQ 3.12 and later nodes will refuse to start.

Minimum Supported Erlang Version

Starting with this release, RabbitMQ requires Erlang 25.0 or later versions. Nodes will fail to start
on older Erlang releases.

Erlang 25 as our new baseline means much improved performance on ARM64 architectures, profiling with flame graphs
across all architectures, and the most recent TLS 1.3 implementation available to all RabbitMQ 3.11 users.

Client Library Compatibility

Client libraries that were compatible with RabbitMQ 3.11.x will be compatible with 3.12.0.

Getting Help

Any questions about this release, upgrades or RabbitMQ in general are welcome on the RabbitMQ mailing list.

Changes Worth Mentioning

Release notes are kept under rabbitmq-server/release-notes.

Core Server

Bug Fixes

All bug fixes worth mentioning in this release have also shipped
in the 3.11.x release series.

Enhancements

• Reduced memory footprint, improved memory use predictability and throughput of classic queues.
  This particularly benefits classic queues with longer backlogs.

  GitHub issues: #4522, #7516

• Reduced peak memory footprint of quorum queues.

  GitHub issue: #7175

• Improved stream leader distribution efficiency. Mostly relevant to environments with lots of
  streams.

  GitHub issue: #6440

• All feature flags introduced before 3.11.0 are now required to be enabled. Make sure
  all feature flags are enabled before upgrading to 3.12.0.

  GitHub issue: #7219

• Plugin and core API: all schema data store operations are now available via the rabbit_db_* modules.
  Plugin maintainers should switch to them for an easier transition to a future 4.0 release.

  GitHub issues: #6430, #6821

• Plugin and core API: node data directory now should be accessed using rabbit:data_dir/0.

  GitHub issue: #6462

• Initial Erlang 26 compatibility

  GitHub issues: #7443,

• There is now a way to pre-configure user permissions for newly created virtual hosts.

  Contributed by @illotum (AWS).

  GitHub issue: #7208.

CLI Tools

Features

• rabbitmq-streams restart_stream is a new command that can be used to kick off
  a new leader election for a stream. This can be used to rebalance stream leaders
  across cluster nodes.

  GitHub issue: #6440

• Classic queue metrics are now available via rabbitmq-diagnostics observer.

  GitHub issue: #3314

• rabbitmqctl set_permissions_globally is a new command that sets up user permissions in all existing virtual hosts.

  GitHub issue: #1000

• rabbitmq-diagnostics cluster_status now lists how many CPU cores are available to individual nodes, plus a total.

  GitHub issue: #7135

MQTT Plugin

Enhancements

• Significant (up to more than 90% with some workloads) reduction in memory footprint of MQTT connections,
  and a double digit % reduction in memory footprint of MQTT-over-WebSockets (Web MQTT) connections.

  GitHub issues: #5895, #7091, #7234

Management Plugin

Enhancements

• Support for Identity Provider-initiated Login (IDP).

  GitHub issues: #6015, #6201,
  #6247

Consul Peer Discovery Plugin

Bug Fixes

• Consul peer discovery now correctly determines if the node uses long or short names.

  Contributed by @SimonUnge (AWS).

  GitHub issue: #4230

Dependency Changes

• ra was upgraded to 2.4.9

Source Code Archives

To obtain source code of the entire distribution, please download the archive named rabbitmq-server-3.12.0.tar.xz
instead of the source tarball produced by GitHub.

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This discussion was created from the release RabbitMQ 3.12.0-beta.1.