In this chapter, we will cover recipes to simplify the configuration of an SOA Suite cluster:
- Gathering configuration information
- Preparing the operating system
- Preparing the database
- Preparing the network
An SOA Suite cluster can process more composite instances by spreading the load across multiple machines, providing greater capacity. It also provides resiliency by allowing composites to continue to execute on remaining machines in the cluster in the event of a machine failing.
Using a cluster provides the following benefits:
- Greater capacity
- Greater resiliency
Oracle provides a comprehensive guide to creating an SOA Suite cluster called the Enterprise Deployment Guide (EDG). Rather than duplicating the guide, this chapter will provide recipes that enhance the guide and elaborate on the steps required.
SOA Suite is normally deployed on a WebLogic application server and in this chapter we will use WebLogic nomenclature to describe SOA Suite entities:
The following figure shows the target SOA Suite deployment architecture for a three-machine SOA Suite cluster:
At the heart of the cluster are three physical machines running SOA Suite. They make use of a highly available database and a shared filesystem. HTTP access to the machines is provided through two web server machines which run HTTP servers. Finally, a load balancer is used to distribute the load across the web servers. See the Preparing the network recipe for more details on the load balancer.
This architecture may be scaled by adding additional SOA machines. For most environments, the two web servers are only required for resilience. They can generally handle all but the highest client loads. Each web server machine will distribute requests to all machines in the SOA Suite cluster; there is no affinity between a particular HTTP machine and a particular SOA machine.
Note that each set of machines forms a layer that may be separated by using firewalls to improve security. If this is not required then the web servers may run on the SOA machines, removing the need for the web machines.
The database is required by SOA Suite to store composite instance state and configuration information. The shared filesystem is required by WebLogic to store shared configuration files, transaction logs, and queues. A highly available database, such as Oracle Real Application Clusters (RAC), is recommended.
An SOA Suite cluster is typically made up of several WebLogic clusters; a Web Services Manager cluster, an SOA cluster, and a BAM cluster. These clusters may share hardware, as shown in the following figure:
Note
An SOA Suite Cluster contains not just the core SOA Suite functionality of BPEL, Mediator, Rules, and Human Workflow but also Web Services Manager and BAM. The Web Services Manager and BAM have their own WebLogic clusters which run alongside the core SOA cluster. Hence, the SOA Suite cluster has within it three WebLogic clusters, one of which, the SOA cluster, has the core SOA Suite functionality.
In our three-machine cluster we have chosen to have an SOA Cluster with three managed servers, a BAM cluster with two managed servers, and a WSM cluster with two managed servers. We can adjust the number of managed servers in a cluster to accommodate different numbers of physical machines. Note that in our example each machine hosts at least two servers, but the machines may host more or fewer servers depending on their capacity (CPU, memory, and network).
The Node Manager is responsible for monitoring the state of the managed servers and restarting them in the event of failure, either on the original machine if possible, or in the event of machine failure on another machine in the cluster.