WebSphere Extended Deployment, Version 6.0.x
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Components of dynamic operations

WebSphere Extended Deployment is built on features of autonomic computing in the dynamic operations environment. With these features the application server environment can expand and contract as the business demands. Using the autonomic managers in the WebSphere Extended Deployment environment, dynamic operations can make logical decisions based on business goals.

The dynamic operations environment has the following components:
Operational policy
An operational policy is a business, or performance objective that supports specific goals for specific requests. Operational policies include service and health policies. A service policy defines a business goal and an importance and contains one or more transaction classes. For a given work class, a rule condition maps to a transaction class which belongs to a service policy to further classify its workload by more specific criteria. This mapping gives the work class its goal. The service policy contains the business goal requirements and the work class contains the work description upon which the service policy is applicable. The combination of these policies is read by the dynamic operations environment to make decisions on HTTP, SOAP, JMS and IIOP work requests.
Node groups
Within WebSphere Extended Deployment, the relationship between applications and the nodes on which they run is expressed in terms of an intermediate construct called a node group. A node group is a pool of computing power, inside of which one or more dynamic clusters is created. The computing power represented by a node group is divided among its dynamic cluster members. This distribution of resources is modified autonomically in accordance with business goals to compensate for changing workload patterns.
Dynamic clusters
A dynamic cluster is an application deployment target that is expandable and contractible, as needed by the dynamic operations environment. Dynamic cluster instances are created on nodes that are members of the node group that is associated with the dynamic cluster.
Autonomic request flow manager
The autonomic request flow manager has numerous functions:
  • Limits concurrency to avoid overloading the current set of WebSphere Application Server instances for a given flow and to manage the competition between deployment targets that compete for node resources.
  • Controls the rate of release requests from the queues.
  • Sends signals to the placement controller. The signals indicate the computing power allocation that best optimizes the performance results given the operational policy and currently offered load.
  • Supplies information to the Tivoli Intelligent Orchestrator about the computing power that is currently available in and ideally needed by each node group.
  • Dispatches requests out of the queues based on weights (one weight per queue, not one per class). Class weights are set by the administrator (manual mode) or autonomically by the controller components of the autonomic request flow manager (automatic mode).
On demand router
The on demand router (ODR) is a type of proxy server in WebSphere Extended Deployment that decides where HTTP requests are routed. The ODR also determines if enough application resources are available to support the work received from the flow control manager. When spikes occur in work requests that require application manipulation, the ODR starts and stops instances of applications accordingly, if the environment is running in the on demand mode.
Dynamic workload manager
The autonomic request flow manager classifies and prioritizes requests to application servers based on the demand and policies. The dynamic workload manager then distributes the requests among the nodes in a node group to balance the work.
Application placement controller
The application placement controller is an autonomic manager in the dynamic operations infrastructure that supports the fluid mobility of applications within a dynamic cluster. The application placement controller adds application instances when the work is more than can be handled by the current application, and stops application instances when there are too few requests for the number of started applications.
Health controller
The health controller constantly monitors the defined health policies. When a condition specified by a health policy is not met in the environment, the health controller assures that the configured actions are taken to correct the problem.
Tivoli Intelligent Orchestrator [For distributed platforms]
The Tivoli Intelligent Orchestrator is an optional piece of the dynamic operations environment. A WebSphere Extended Deployment environment with Tivoli Intelligent Orchestrator integration supports the ability to dynamically allocate additional hardware to the environment.
EWLM
The enterprise workload manager (EWLM) manages sub-goals and resource allocations for the larger environment which contains WebSphere Extended Deployment.



Related concepts
Overview of dynamic operations
Operational policies
Related tasks
Configuring health management
Configuring Tivoli Intelligent Orchestrator to work with WebSphere Extended Deployment
Enabling the on demand router to work with IBM Enterprise Workload Manager
Configuring dynamic application placement
Creating ODRs
Configuring the autonomic request flow manager
Creating dynamic clusters
Deploying applications with defined service levels
Concept topic    

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Last updated: Nov 30, 2007 3:56:25 PM EST
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