WebSphere Extended Deployment, Version 6.0.x
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Overview of application placement

Dynamic application placement for Internet InterORB Protocol (IIOP), Java Message Service (JMS), and HTTP request types is achieved through the cooperation of various product components. These components include node groups, dynamic clusters, the on demand router (ODR) and associated autonomic managers, and the application placement controller. The fluctuating volume of work requests for applications is dynamically met on the application server side by the application placement feature, which ensures the integrity of the defined business goals.

Application placement is a natural extension to the request flow prioritization feature. While the ODR and its associated autonomic managers ensure that the work flows appropriately according to the defined policy, the application placement feature ensures that the applications and the nodes that they run on are kept at appropriate levels to support the influx of work. In times of less work flow, the application instances that run within the resource pool are kept at a minimum. In times of significant work flow, the application instances that run are increased to keep pace with the requests.

The following image shows the application placement process for a stock trading firm in times of less demanding workflow; that is, the request flow is during an off-peak hour. The ODR and its managers are controlling the incoming request flow prioritization. The decision making unit of the application placement function is made aware of the service policy for the incoming Universal Resource Identifier (URI) requests, as well as the demand level for the given application server resources. As a result, the application instances that run are comfortable for the given demand.

Application placement during light workflow

The following image shows a sudden increase in incoming URI requests occurs. For example, it is now lunch time and all online trade customers are now free to access the Web for personal use. The sudden work request fluctuation, which in other environments requires manual intervention to address, is handled by the autonomic features of dynamic operations.

Application placement during increased workflow

During times of more robust request flow, the application placement function must ensure that the business goals created for the many application URIs are met. As a result, the autonomic managers of dynamic operations must work together to bring a balance to the environment. You can see this balance achieved in the previous graphic. The work flow fluctuation is met by increasing the application instances that run on the available nodes, while balancing the service policy definitions. When the peak declines, the application placement function reduces the running number of application instances accordingly.

The functionality of dynamic application placement requires fundamental WebSphere® Extended Deployment components. Application placement requires node groups, dynamic clusters and service policies. Node groups are resource pools of nodes with common capabilities. Dynamic clusters are application deployment targets and are tightly integrated with a node group. Service policies are performance goals that are assigned to a specific application URI.

These components, when integrated with the autonomic managers, support dynamic application placement.




Related concepts
Overview of request flow prioritization
Related tasks
Configuring dynamic application placement
Configuring the autonomic request flow manager
Concept topic    

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Last updated: Oct 16, 2009 11:07:34 AM EDT
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