Before you begin
Download and install the Apache httpd including mod_jk support and make sure it is running properly. For more information about how to install and run Apache httpd, refer to the official Apache documentation.
Download and install the Apache ActiveMQ standard distribution and run it. For more information about how to install and run Apache ActiveMQ on your platform, refer to the Apache ActiveMQ documentation.
- Install the first MDM Server as you would for an installation on a single machine.
Duplicate this first instance on as many machines as you want to include in
your cluster. In this case, duplicate means rerun the installation process with
exactly the same parameters each time.
Note that you can also work with multiple instances on the same physical server, using different port numbers, but in this case you do not have the same level of protection against the physical failure of a machine.
- On each MDM Server instance, open the <$INSTALLDIR>/conf/mdm.conf file to edit it.
Add the line
System Settingssection to enable the clustering configuration.
Change the value of
tcp://AMQHOST:AMQPORT, for example,
AMQHOSTis the name of the server hosting ActiveMQ, and
AMQPORTis the OpenWire TCP port that Apache ActiveMQ listens to.Note: By default, an MDM server uses an embedded Apache ActiveMQ broker as the JMS provider. In order to ensure correct communication between nodes, the JMS broker must be externalized and shared by every node of the cluster.
Add the following two lines to let MDM create authenticated connections to the
In the file <TomcatPath>/conf/server.xml, locate the
<Engine>element and add an attribute for
<Engine name="Catalina" defaultHost="localhost" jvmRoute="mdm_node1">
Here the value of
jvmRouterepresents the unique identifier of each MDM server node included in the cluster and must correspond to the worker name in the worker.properties file.
For a specific example about how to set up a load balancer using Apache httpd with mod_jk support, see An example of how to set up a load balancing solution using Apache httpd and mod_jk.
- Repeat the previous for each server instance.
- Restart all the MDM nodes in the cluster.
Full-text index replication is implemented within each MDM cluster. For more information, see Full-text index replication.
Once you have installed and configured all the required MDM Server instances, you need to explicitly connect them together in a cluster. Different solutions exist for doing so, both hardware and software. For an example of doing so, see An example of how to set up a load balancing solution using Apache httpd and mod_jk.