{"id":24172,"date":"2014-04-17T16:00:48","date_gmt":"2014-04-17T13:00:48","guid":{"rendered":"http:\/\/www.javacodegeeks.com\/?p=24172"},"modified":"2014-04-17T09:59:28","modified_gmt":"2014-04-17T06:59:28","slug":"activemq-network-of-brokers-explained","status":"publish","type":"post","link":"https:\/\/www.javacodegeeks.com\/2014\/04\/activemq-network-of-brokers-explained.html","title":{"rendered":"ActiveMQ – Network of Brokers Explained"},"content":{"rendered":"

Objective<\/h2>\n

This 7 part blog series is to share about how to create network of ActiveMQ brokers in order to achieve high availability and scalability.<\/p>\n

Why network of brokers?<\/h3>\n

ActiveMQ message broker is a core component of messaging infrastructure in an enterprise. It needs to be highly available and dynamically scalable to facilitate communication between dynamic heterogeneous distributed applications which have varying capacity needs.<\/p>\n

Scaling enterprise applications on commodity hardware is a rage nowadays. ActiveMQ caters to that very well by being able to create a network of brokers to share the load.<\/p>\n

Many times applications running across geographically distributed data centers need to coordinate messages. Running message producers and consumers across geographic regions\/data centers can be architected better using network of brokers.<\/p>\n

ActiveMQ uses transport connectors over which it communicates with message producers and consumers. However, in order to facilitate broker to broker communication, ActiveMQ uses network connectors<\/b>.<\/p>\n

\n

A network connector is a bridge between two brokers which allows on-demand message forwarding.<\/p>\n<\/blockquote>\n

In other words, if Broker B1 initiates a network connector to Broker B2 then the messages on a channel (queue\/topic) on B1 get forwarded to B2 if there is at least one consumer on B2 for the same channel. If the network connector was configured to be duplex, the messages get forwarded from B2 to B1 on demand.<\/p>\n

This is very interesting because it is now possible for brokers to communicate with each other dynamically.<\/p>\n

In this 7 part blog series, we will look into the following topics to gain understanding of this very powerful ActiveMQ feature:<\/p>\n

    \n
      \n
    1. Network Connector Basics – Part 1<\/li>\n
    2. Duplex network connectors – Part 2<\/li>\n
    3. Load balancing consumers on local\/remote brokers – Part 3<\/li>\n
    4. Load-balance consumers\/subscribers on remote brokers\n
        \n
      1. Queue: Load balance remote concurrent consumers\u00a0– Part 4<\/li>\n
      2. Topic: Load Balance Durable Subscriptions on Remote Brokers – Part 5<\/li>\n<\/ol>\n<\/li>\n
      3. Store\/Forward messages and consumer failover\u00a0\u00a0– Part 6\n
          \n
        1. How to prevent stuck\u00a0\u00a0messages<\/li>\n<\/ol>\n<\/li>\n
        2. Virtual Destinations – Part 7<\/li>\n<\/ol>\n<\/ol>\n

          To give credit where it is due, the following URLs have helped me in creating this blog post series.<\/p>\n

            \n
          1. Advanced Messaging with ActiveMQ<\/a>\u00a0by\u00a0Dejan Bosanac<\/a>\u00a0[Slides\u00a032-36]<\/li>\n
          2. Understanding ActiveMQ Broker Networks<\/a>\u00a0by\u00a0Jakub Korab<\/a><\/li>\n<\/ol>\n

            Prerequisites<\/h4>\n
              \n
            1. ActiveMQ 5.8.0 \u2013 To create broker instances<\/li>\n
            2. Apache Ant \u2013 To run ActiveMQ sample producer and consumers for demo.<\/li>\n<\/ol>\n

              We will use multiple ActiveMQ broker instances on the same machine for the ease of demonstration.<\/p>\n

              Network Connector Basics – Part 1<\/h2>\n

              The following diagram shows how a network connector functions. It bridges two brokers and is used to forward messages from Broker-1 to Broker-2 on demand if established by Broker-1 to Broker-2.<\/p>\n

              \"NC\"<\/a><\/p>\n

              A network connector can be duplex so messages could be forwarded in the opposite direction; from Broker-2 to Broker-1, once there is a consumer on Broker-1 for a channel which exists in Broker-2. More on this in Part 2

              <\/div> <\/div><\/p>\n

              Setup network connector between broker-1 and broker-2<\/h3>\n