Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

Amazon MQ Network of brokers

Amazon MQ supports ActiveMQ's network of brokers feature.

A network of brokers is comprised of multiple simultaneously active single-instance brokers or active/standby brokers. You can configure networks of brokers in a variety of topologies (for example, concentrator, hub-and-spokes, tree, or mesh), depending on your application's needs, such as high availability and scalability. For instance, a hub and spoke network of brokers can increase resiliency, preserving messages if one broker is not reachable. A network of brokers with a concentrator topology can collect messages from a larger number of brokers accepting incoming messages, and concentrate them to more central brokers, to better handle the load of many incoming messages.

For a tutorial and detailed configuration information, see the following:

The following are benefits of using a network of brokers:

How does a network of brokers work?

Amazon MQ supports the ActiveMQ network of brokers feature in a number of ways. First, you can edit the parameters within each broker's configuration to create a network of brokers, just as you would with native ActiveMQ. Second, Amazon MQ has sample blueprints that use Amazon CloudFormation to automate the creation of a network of brokers. You can deploy these sample blueprints directly from the Amazon MQ console, or you can edit the related Amazon CloudFormation templates to create your own topologies and configurations.

A network of brokers is established by connecting one broker to another using network connectors. Once connected, these brokers provide message forwarding. For instance, if Broker1 establishes a network connector to Broker2, messages on Broker1 are forwarded to Broker2 if there is a consumer on that broker for the queue or topic. If the network connector is configured as duplex, messages are also forwarded from Broker2 to Broker1. Network connectors are configured in the broker configuration. See, Configuration. For instance, here is an example networkConnector entry in a broker configuration:

<networkConnectors>
  <networkConnector name="connector_1_to_2" userName="myCommonUser" duplex="true"
    uri="static:(ssl://b-1234a5b6-78cd-901e-2fgh-3i45j6k178l9-1.mq.us-east-2.amazonaws.com:61617)"/>
</networkConnectors>

A network of brokers ensures that messages flow from one broker instance to another, forwarding messages only to the broker instances that have corresponding consumers. For the benefit of broker instances adjacent to each other within the network, ActiveMQ sends messages to advisory topics about producers and consumers connecting to and disconnecting from the network. When a broker instance receives information about a consumer that consumes from a particular destination, the broker instance begins to forward messages. For more information, see Advisory Topics in the ActiveMQ documentation.

How Does a Network of Brokers Handle Credentials?

For broker A to connect to broker B in a network, broker A must use valid credentials, like any other producer or consumer. Instead of providing a password in broker A's <networkConnector> configuration, you must first create a user on broker A with the same values as another user on broker B (these are separate, unique users that share the same username and password values). When you specify the userName attribute in the <networkConnector> configuration, Amazon MQ will add the password automatically at runtime.

Brokers must be in the same VPC or in peered VPCs. For more information, see Prerequisites in the Creating and Configuring a Network of Brokers tutorial.

Sample blueprints

To get started using a Network of Brokers, Amazon MQ provides sample blueprints. These sample blueprints create a Network of Brokers deployment, and all related resources using, Amazon CloudFormation. The two sample blueprints available are:

From the Create brokers page, select one of the sample blueprints and choose Next. Once the resources have been created, review the generated brokers and their configurations in the Amazon MQ console.

By creating brokers and configuring different networkConnector elements in the broker configurations, you can create a network of brokers in many different topologies. For more information on configuring a network of brokers, see Networks of Brokers in the ActiveMQ documentation.

Network of brokers topologies

By deploying brokers, and then configuring networkConnector entries in their configurations, you can build a network of brokers using different network topologies. A network connector provides on-demand message forwarding between connected brokers. Connections can be configured as duplex, where messages are forwarded both ways between brokers, or not duplex, where the forwarding only propagates from one broker to the other. For example, if we have a duplex connection between Broker1 and Broker2, messages will be forwarded from each to the other if there is a consumer.

With a duplex network connector, messages are forwarded from each broker to the other. These are forwarded on-demand: if there is a consumer on Broker2 for a message on Broker1, the message is forwarded. Similarly, if there is a consumer on Broker1 for a message on Broker2 the message is also forwarded.

For non-duplex connections, messages are forwarded only from one broker to the other. In this example, if there is a consumer on Broker2 for a message on Broker1, the message is forwarded. But messages will not be forwarded from Broker2 to Broker1.

Using both duplex and non-duplex network connectors, it is possible to build a network of brokers in any number of network topologies.

Mesh topology

A mesh topology provides multiple brokers that are all connected to each other. This simple example connects three single-instance brokers, but you can configure more brokers as a mesh.

This topology, and one that includes a mesh of active/standby pairs of brokers, can be created using sample blueprints in the Amazon MQ console. You can create these sample blueprint deployment to see a working network of brokers, and review how they are configured.

You can configure a three broker mesh network like this by adding a network connector to Broker1 that makes duplex connections to both Broker2 and Broker3, and a single duplex connection between Broker2 and Broker3.

Network connectors for Broker1:

<networkConnectors>
    <networkConnector name="connector_1_to_2" userName="myCommonUser" duplex="true"
        uri="static:(ssl://b-9876l5k4-32ji-109h-8gfe-7d65c4b132a1-2.mq.us-east-2.amazonaws.com:61617)"/>
    <networkConnector name="connector_1_to_3" userName="myCommonUser" duplex="true"
        uri="static:(ssl://b-743c885d-2244-4c95-af67-a85017ff234e-3.mq.us-east-2.amazonaws.com:61617)"/>
</networkConnectors>

Network connectors for Broker2:

<networkConnectors>
    <networkConnector name="connector_2_to_3" userName="myCommonUser" duplex="true"
        uri="static:(ssl://b-743c885d-2244-4c95-af67-a85017ff234e-3.mq.us-east-2.amazonaws.com:61617)"/>
</networkConnectors>

By adding the above connectors to the configurations of Broker1 and Broker2, you can create a mesh between these three brokers that forwards message between all the brokers on demand. For more information, see Amazon MQ Broker Configuration Parameters.

Hub and Spoke Topology

In a hub and spoke topology, messages are preserved if there is a disruption to any broker on a spoke. Messages are forwarded throughout, and only the central Broker1 is critical to the network’s operation.

To configure the hub and spoke network of brokers in this example, you could add a networkConnector to each of the brokers on the spokes in the configuration of Broker1.

<networkConnectors>
    <networkConnector name="connector_hub_and_spoke_2" userName="myCommonUser" duplex="true"
        uri="static:(ssl://b-1234a5b6-78cd-901e-2fgh-3i45j6k178l9-1.mq.us-east-2.amazonaws.com:61617)"/>
    <networkConnector name="connector_hub_and_spoke_3" userName="myCommonUser" duplex="true"
        uri="static:(ssl://b-9876l5k4-32ji-109h-8gfe-7d65c4b132a1-2.mq.us-east-2.amazonaws.com:61617)"/>
    <networkConnector name="connector_hub_and_spoke_4" userName="myCommonUser" duplex="true"
        uri="static:(ssl://b-743c885d-2244-4c95-af67-a85017ff234e-3.mq.us-east-2.amazonaws.com:61617)"/>
    <networkConnector name="connector_hub_and_spoke_5" userName="myCommonUser" duplex="true"
        uri="static:(ssl://b-62a7fb31-d51c-466a-a873-905cd660b553-4.mq.us-east-2.amazonaws.com:61617)"/>
</networkConnectors>

Concentrator topology

In this example topology, the three brokers on the bottom can handle a large number of connections, and those messages are concentrated to Broker1 and Broker2. Each of the other brokers has a non-duplex connection to the more central brokers. To scale the capacity of this topology, you can add additional brokers that receive messages and concentrate those messages in Broker1 and Broker2.

To configure this topology, each of the brokers on the bottom would contain a network connector to each of the brokers they are concentrating messages to.

Network connectors for Broker3:

<networkConnectors>
    <networkConnector name="3_to_1" userName="myCommonUser" duplex="false"
        uri="static:(ssl://b-1234a5b6-78cd-901e-2fgh-3i45j6k178l9-1.mq.us-east-2.amazonaws.com:61617)"/>
    <networkConnector name="3_to_2" userName="myCommonUser" duplex="false"
        uri="static:(ssl://b-9876l5k4-32ji-109h-8gfe-7d65c4b132a1-2.mq.us-east-2.amazonaws.com:61617)"/>
</networkConnectors>

Network connectors for Broker4:

<networkConnectors>
    <networkConnector name="4_to_1" userName="myCommonUser" duplex="false"
        uri="static:(ssl://b-1234a5b6-78cd-901e-2fgh-3i45j6k178l9-1.mq.us-east-2.amazonaws.com:61617)"/>
    <networkConnector name="4_to_2" userName="myCommonUser" duplex="false"
        uri="static:(ssl://b-1234a5b6-78cd-901e-2fgh-3i45j6k178l9-1.mq.us-east-2.amazonaws.com:61617)"/>
</networkConnectors>

Network connectors for Broker5:

<networkConnectors>
    <networkConnector name="5_to_1" userName="myCommonUser" duplex="false"
        uri="static:(ssl://b-1234a5b6-78cd-901e-2fgh-3i45j6k178l9-1.mq.us-east-2.amazonaws.com:61617)"/>
    <networkConnector name="5_to_2" userName="myCommonUser" duplex="false"
        uri="static:(ssl://b-9876l5k4-32ji-109h-8gfe-7d65c4b132a1-2.mq.us-east-2.amazonaws.com:61617)"/>
</networkConnectors>

Cross region

To configure a network of brokers that spans Amazon regions, deploy brokers in those regions, and configure network connectors to the endpoints of those brokers.

To configure a network of brokers like this example, you could add networkConnectors entries to the configurations of Broker1 and Broker4 that reference the wire-level endpoints of those brokers.

Network connectors for Broker1:

<networkConnectors>
    <networkConnector name="1_to_2" userName="myCommonUser" duplex="true"
        uri="static:(ssl://b-9876l5k4-32ji-109h-8gfe-7d65c4b132a1-2.mq.us-east-2.amazonaws.com:61617)"/>
    <networkConnector name="1_to_3" userName="myCommonUser" duplex="true"
        uri="static:(ssl://b-743c885d-2244-4c95-af67-a85017ff234e-3.mq.us-east-2.amazonaws.com:61617)"/>
    <networkConnector name="1_to_4" userName="myCommonUser" duplex="true"
        uri="static:(ssl://b-62a7fb31-d51c-466a-a873-905cd660b553-4.mq.us-east-2.amazonaws.com:61617)"/>
</networkConnectors>

Network connector for Broker2:

<networkConnectors>
    <networkConnector name="2_to_3" userName="myCommonUser" duplex="true"
        uri="static:(ssl://b-743c885d-2244-4c95-af67-a85017ff234e-3.mq.us-east-2.amazonaws.com:61617)"/>
</networkConnectors>

Network connectors for Broker4:

<networkConnectors>
    <networkConnector name="4_to_3" userName="myCommonUser" duplex="true"
        uri="static:(ssl://b-743c885d-2244-4c95-af67-a85017ff234e-3.mq.us-east-2.amazonaws.com:61617)"/>
    <networkConnector name="4_to_2" userName="myCommonUser" duplex="true"
        uri="static:(ssl://b-9876l5k4-32ji-109h-8gfe-7d65c4b132a1-2.mq.us-east-2.amazonaws.com:61617)"/>      
</networkConnectors>

Dynamic Failover With Transport Connectors

In addition to configuring networkConnector elements, you can configure your broker transportConnector options to enable dynamic failover, and to rebalance connections when brokers are added or removed from the network.

<transportConnectors>
  <transportConnector name="openwire" updateClusterClients="true" rebalanceClusterClients="true" updateClusterClientsOnRemove="true"/>
</transportConnectors>

In this example both updateClusterClients and rebalanceClusterClients are set to true. In this case clients will be provided a list of brokers in the network, and will request them to rebalance if a new broker joins.

Available options:

When updateClusterClients is set to true, clients can be configured to connect to a single broker in a network of brokers.

failover:(ssl://b-1234a5b6-78cd-901e-2fgh-3i45j6k178l9-1.mq.us-east-2.amazonaws.com:61617)

When a new broker connects, it will receive a list of URIs of all brokers in the network. If the connection to the broker fails, it can dynamically switch to one of the brokers provided when it connected.

For more information on failover, see Broker-side Options for Failover in the Active MQ documentation.