rabbitmq/rabbitmq-server v3.10.0-rc.4

RabbitMQ 3.10.0-rc.4

on GitHub

Highlights

This release improves efficiency of quorum and classic queues. Per-queue memory footprint was reduced for some
workloads. Queue operations produce less runtime GC pressure.

Quorum queues now support message TTL, at-most-once and at-least-once
strategies for dead-lettering, an operationally safer re-queue operation behavior,
and can be used for durable MQTT subscriptions in new clusters.

3.10.0 is the first release to introduce Erlang 25 support (at RC stage at the time of writing).

Classic queues now ship a new message store and queue index implementation known as CQv2.
The operator must opt in to use them, CQv1 is still used by default.

Definition re-import on node restart now can be skipped if the source (a file, directory or a file retrieved over HTTPS)
has not changed. Queue and exchange re-import is now more efficient, the speed-up is over two orders of magnitude
in some environments.

The OAuth 2 plugin provides a way to map "non-standard" or "alias" scopes
to a set of RabbitMQ permissions.

Obtaining Packages

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

Erlang/OTP Compatibility Notes

This release requires Erlang 23.2 or later. Erlang 24 is recommended as it offers 20%-50% throughput improvements for many workloads.

Provisioning Latest Erlang Releases explains what package repositories and tools can be used to provision latest patch versions of Erlang 23.3.x and 24.x.

Upgrading to 3.10

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

RabbitMQ 3.10.0 nodes can run alongside 3.9.x nodes. 3.10.x-specific features can only be made available when all nodes in the cluster
upgrade to 3.10.0 or any other patch release in the 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 3.10.0, 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

Client Library Compatibility

Client libraries that were compatible with RabbitMQ 3.9.x will be compatible with 3.10.0.

Upgrading to Erlang 24.x

RabbitMQ 3.8.16 and later require Erlang 23.2 and support Erlang 24 (recommended).
Users of RabbitMQ versions that do not support Erlang 23.2 should first upgrade to the latest 3.8.x patch release on Erlang 23.2,
then upgrade to 3.10.0, and ideally Erlang 24.

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

Enhancements

• Reduced memory footprint of quorum queues. Quorum queues now move enqueues messages to disk as quickly as
  possible, ignoring the x-max-in-memory-length and x-max-in-memory-bytes policy keys. This reduces per-queue memory footprint
  and makes throughput and latency less variable.

  GitHub issue: #3898

• New classic queue index and message store implementations. This makes memory footprint of classic queues less variable
  and on average, lower than before. Consumer delivery is more efficient, potentially increasing throughput for workloads
  where consumers do keep up with producers.

  This implementation is not enabled by default. It can be enabled using a policy:

  rabbitmqctl set_policy cq_version "^cq\." '{"queue-version": 2}' --priority 1 --apply-to queues

  or set via rabbitmq.conf:

  classic_queue.default_version = 2

  GitHub issue: #3029

• Quorum queues now support message TTL.

  GitHub issue: #3121

• Reduced per-queue garbage collection.

  GitHub issue: #4110

• Stream replication connections now adopt TLS settings configured for inter-node communication links.

  GitHub issue: #3553

• Quorum queues now support two dead lettering strategies, at-most-once (the 3.9 quorum queue and classic queue behavior)
  and at-least-once.

  To use at-least-once the user must opt-in.

  GitHub issue: #3100

• Messages delivered by a quorum queue and negatively acknowledged with a requeue will be added to the back of the queue
  until the queue has redelivery limit set. With a redelivery limit, requeueing will use the original position of the message
  if possible.

  This improves operational safety: consumers that get stuck or requeue deliveries at a high rate will not indefinitely
  grow quorum queue Raft log, potentially driving the node out of disk space.

  This is a potentially breaking change.
  Applications can make sure quorum queues have a redelivery limit
  set if the original behavior is important to keep.

  GitHub issue: #3776

• Boot time definition sync now can be skipped if definition source (e.g. file or directory) contents
  have not changed:

  definitions.skip_if_unchanged = true
  
  definitions.import_backend = local_filesystem
  definitions.local.path = /path/to/definitions/defs.json

  GitHub issue: #4062

• Classic mirrored queues peak eager sync throughput now can be limited.

  Contributed by @thuandb (AWS).

  GitHub issue: #3925

• Optional queue arguments are now more strictly validated at queue
  declaration time, as are optional consumer arguments when new consumers subscribe.

  GitHub issue: #4572

• Headers exchanges (AMQP 0-9-1) now support a new matching strategy, "any-with-x",
  which works the same way as "any" but also considers headers that begin with
  an "x-".

  GitHub issue: #4143

• Queues can no longer be created in a vhost while deletion of that vhost is in progress

  Contributed by @tomyouyou.

  GitHub issue: #4260

• rabbitmqctl encode/decode can now accept more values via standard input

  GitHub issue: #4258

• rabbitmq_tracing now uses local time for timestamps

  GitHub issue: #4277

Internal API and Other Changes

• Two rarely used classic queue metrics have been removed. Their removal reduces pressure
  on internal table writes and boosts classic queue v1 throughput by 10 to 20 percent.

  Contributed by @felixhuettner.

  GitHub issue: #4431

• Tracing and idle_since timestamps now reflect local time in RFC 3339 format. Previously
  a custom format was used for these timestamps and they always reflected UTC time.

  GitHub issue: #4276

• Inter-node message transfer is optimized for the case where a message is only routed to one queue.

  Contributed by @tomyouyou.

  GitHub issue: #3865

• Definition import now can be extended to support arbitrary sources. This is done
  by providing a module that implements three functions: is_enabled/0, load/1, load_with_hashing/3.
  The module can then should be specified as the definitions.import_backend value:

  definitions.import_backend = rabbit_definitions_import_our_custom_backend

  GitHub issue: #3311

• Elixir 1.13 is now supported at build time.

  GitHub issue: #4108

Bug Fixes

This release includes all applicable bug fixes that shipped in 3.9.x releases.

• Addressed a performance regression for large fanouts when streams were not enabled.

  GitHub issue: #4073

• Stream delivery rate could drop if concurrent stream consumers consumed in a way
  that made them reach the end of the stream often.

  GitHub issue: #4371

• Channels could confirm a subset of messages published as mandatory in some cases.

  GitHub issue: #3870

• Direct Erlang client initialisation had a race condition with earlier boot steps,
  which could lead plugins that depend on it to fail to open connections.

  GitHub issue: #3685

• Exclusive queues are always placed on local node.

  Exclusive queues are by definition node-local because they are tied to the lifecycle of
  their declaring connection, which is node-local.

  GitHub issue: #3341

Prometheus Plugin

Bug Fixes

• Prometheus collector could run into an exception early on node's
  schema database sync.

  GitHub issue: #4376

Management Plugin

Enhancements

• idle_since field now uses RFC 3339 format.

  This is a potentially breaking change.
  Sample value with the previous format: 2022-03-22 11:39:37. With the new format: 2022-03-22T11:39:37.908+01:00.
  Clients of the REST API should be able to parse values in the new format.

  GitHub issue: #4276

Bug Fixes

• rabbitmqadmin now correctly loads TLS-related keys from its configuration file.

  Contributed by @fwolfsjaeger.

  GitHub issue: #4408

MQTT Plugin

Enhancements

• Durable (QoS 1) subscriptions now can be backed by quorum queues if configured so.

  This setting can only be applied for new clusters: existing durable classic
  queues will not be converted. Enabling this setting in a cluster with existing
  durable subscription data of MQTT clients will make it impossible for them to
  subscribe without explicit queue deletion by the cluster operator.

  To opt in to use quorum queues for durable MQTT subscriptions, use the mqtt.durable_queue_type
  configuration key in rabbitmq.conf:

  mqtt.durable_queue_type = quorum

  GitHub issue: #4401

OAuth 2 AuthN and AuthZ Backend Plugin

Enhancements

• The plugin now supports scope aliases. In some environments, it's unrealistic to
  adopt JWTs that follow the scope convention assumed by the plugin. Instead,
  identity services fill scope or claims field with a "role name" or "role alias"
  that implicitly maps to a set of scopes/permissions.

  With this feature, RabbitMQ operators can map those values to a set of
  scopes that can be translated to RabbitMQ permissions.

  GitHub issue: #4588

• Improvements to JKW support and new HTTPS settings.

  Contributed by @anhanhnguyen (Erlang Solutions).

  GitHub issue: #3887

Shovel Plugin

Enhancements

• Dynamic Shovels can be deleted or restarted from any cluster node

  Contributed by @kostakal.

  GitHub issue: #4242

Bug Fixes

• Shovels with automatic deletion threshold of 0 are now correctly deleted immediately.

  Contribited by @luos (Erlang Solutions).

  GitHub issue: #4098

Consul Peer Discovery Plugin

Bug Fixes

• Handle a response code change in Consul 1.11.

  Contributed by @maestroes.

  GitHub issue: #4149

Dependency Changes

• ra upgraded from 2.0.0 to 2.0.9
• osiris upgraded from 1.0.0 to 1.2.5
• ranch upgraded from 2.0.0 to 2.1.0
• prometheus upgraded from 4.8.1 to 4.8.2
• eetcd upgraded from 0.3.3 to 0.3.5
• observer_cli upgraded from 1.6.2 to 1.7.3
• gen_batch_server upgraded from 0.8.6 to 0.8.7