RabbitMQ 4

AMQP 1.0 as a core protocol: For more information, see Protocols.

Local shovels: Shovels now support a new protocol called "local" in addition to AMQP 0-9-1 and AMQP 1.0. Local shovels are internally based on AMQP 1.0 but instead of using separate TCP connections, they use intra-cluster connections between cluster nodes and internal APIs for publishing and consuming messages. This can only be used for consuming and publishing within the same cluster and can offer higher throughput while using fewer resources than AMQP 0-9-1 and AMQP 1.0.

Quorum queues support message priorities: Quorum queue message priorities are always active and do not require a policy to work. As soon as a quorum queue receives a message with a priority set it will enable prioritization. Quorum queues internally only support two priorities - high and normal. Messages without a priority set will be mapped to normal as will priorities 0 - 4. Messages with a priority higher than 4 will be mapped to high. High priority messages will be favoured over normal priority messages at a ratio of 2:1, i.e. for every 2 high priority message the queue will deliver 1 normal priority message (if available). Hence, quorum queues implement a kind of non-strict, "fair share" priority processing. This ensures progress is always made on normal priority messages, but high priorities are favoured at a ratio of 2:1.

Khepri: Khepri is used as the default metadata store for RabbitMQ 4 brokers

Mirroring of classic queues: Classic queues continue to be supported without any breaking changes for client libraries and applications, but they are now a non-replicated queue type. Clients will be able to connect to any node to publish to and consume from any non-replicated classic queues. Quorum queues are recommended for replication and data safety.

Removal of Global QoS: Customers are recommended to set per-consumer QoS (non-global) instead of Global QoS, where a single shared prefetch is used for an entire channel.

Support for transient, non-exclusive queues: Transient queues are queues whose lifetime is linked to the uptime of the node they are declared on. In a single instance broker, they are removed when the node is restarted. In a cluster deployment, they are removed when the node they are hosted on is restarted. We recommend using queue TTL for auto-deleting unused, idle queues after some time of inactivity. Exclusive queues continue to be supported and are deleted once all connections to the queue have been removed.

Default queue type: The default queue type on a RabbitMQ 4 broker is set to quorum. If no queue type argument is specified during queue creation, a quorum queue will be created.

Default redelivery limit on quorum queues is set to 20: Messages that are redelivered 20 times or more will be dead-lettered or dropped (removed). If 20 deliveries per message is a common scenario for a queue, a dead-lettering target or a higher limit must be configured for such queues to avoid data loss. The recommended way of doing that is via a policy.

amqplib: Node JS client amqplib versions older than 0.10.7 or any AMQP client library using frame_max < 8192 will not be able to connect to RabbitMQ

Default resource limits: Amazon MQ for RabbitMQ has introduced default resource usage limits for connections, channels, consumers per channel, queues, vhosts, shovels, exchanges, and maximum message size. These serve as guardrails to protect broker availability and can be customized using configurations to match your specific requirements.

Local Random exchanges: Local random exchanges are not supported on Amazon MQ since the Amazon MQ nodes are behind a network load balancer.

Message Interceptor: RabbitMQ message interceptors are not supported on Amazon MQ.

Per queue metrics: Amazon MQ will not vend RabbitMQ queue metrics for RabbitMQ 4 brokers through AWS CloudWatch. Amazon MQ will still provide broker level metrics through AWS CloudWatch. You can query queue metrics using the RabbitMQ management API. We recommend querying metrics for specific queues at a frequency of one minute or longer intervals.