RabbitMQ 3.9.24

[michaelklishin]

RabbitMQ 3.9.24 is a maintenance release in the 3.9.x release series.

Please refer to the Upgrading to 3.9 section from v3.9.0 release notes if upgrading from a version prior to 3.9.0.

This release requires at least Erlang 24.2, and supports Erlang 25. RabbitMQ and Erlang/OTP Compatibility Matrix has more details on Erlang version requirements for RabbitMQ.

Minimum Supported Erlang Version

Erlang 23 support has reached its end of support.

Starting with this release, RabbitMQ requires Erlang 24.2 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.

Open File Handle Limit is Capped by Default on Linux, *BSD, macOS

Nodes now default to 65536 concurrent client connections instead of using the effective kernel open file handle limit.
Users who want to override this default, that is, have nodes that should support more concurrent connections and open files,
now have to perform an additional configuration step:

• Pick a new limit value they would like to use, for instance, 100K
• Set the maximum open file handle limit (for example, via systemd or similar tooling) for the OS user used by RabbitMQ to 100K
• Set the ERL_MAX_PORTS environment variable to 100K

This change was introduced because of a change in several Linux distributions: they now use a default open file handle limit so high,
they cause a significant (say, 1.5 GiB) memory preallocated the Erlang runtime.

For example, RHEL 9 and CentOS Stream 9 are examples of such distributions.
The new default comes from modern systemd.

See rabbitmq/rabbitmq-server#5684 and docker-library/rabbitmq#545
for details.

Changes Worth Mentioning

Release notes can be found on GitHub at rabbitmq-server/release-notes.

Changes Worth Mentioning

Release notes can be found on GitHub at rabbitmq-server/release-notes.

Core Server

Bug Fixes

• Intra-cluster communication link metric collector could run into an exception when
  peer connection has just been re-established, e.g. after a peer node restart.

  GitHub issue: #6127

MQTT Plugin

Bug Fixes

• When a node was put into maintenance mode, it closed all MQTT client connections
  cluster-wide instead of just local client connections.

  GitHub issue: #6108

Dependency Upgrades

None in this release.

Source Code Archives

To obtain source code of the entire distribution, please download the archive named rabbitmq-server-3.9.24.tar.xz
instead of the source tarball produced by GitHub.

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This discussion was created from the release RabbitMQ 3.9.24.