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Draft Article on WAS V6 System Management and Configuration

WebSphere Application Server V6 System Management and Configuration

The versions and product overview is covered by WAS article.

Service Data Objects (SDO) provide unified data access and representation across heterogeneous data stores. Not to replace other data access technologies, it provides another choice

Clients query a data mediator and data mediators access the data stores. Clients get a data graph in response. The data graph is structured data objects that represent a data store. Clients update the data graph and send it back to the mediator service to have the updates applied.

SDO simplifies application programming required to access data stores. SDO support is includes _ Support for SDO naming and packaging _ Externalization of the following APIs _ SDO Core APIs _ EJB Mediator for entity EJBs _ JDBC Data Mediator for relational databases supported by WebSphere Application Serve

The application server is the primary runtime component in all configurations. It is where an application executes. All WebSphere Application Server configurations can have one or more application servers. In the Express and Base configurations, each application server functions as a separate entity. There is no workload distribution or common administration among application servers. With Network Deployment, you can build a distributed server environment consisting of multiple application servers maintained from a central administration point. In a distributed server environment, you can cluster application servers for workload distribution.

Nodes, node groups, and node agents
A node is a logical grouping of server processes managed by WebSphere. A node groups server processes that share common configuration and operation control. A node is associated with one physical installation of WebSphere Application Server. In a stand-alone application server there is only one node. With Network Deployment, multiple nodes can be set up to manage from one common administration server. In this configurations, each node has a node agent that works with a deployment manager to oversee administration processes.

A node group was introduced with WebSphere Application Server V6 and is a grouping of nodes within a cell that have similar capabilities. A node group validates that the node is capable of performing certain functions before allowing those functions. For example, a cluster cannot contain both z/OS nodes and non-z/OS nodes. In this case, two node groups are defined, one for the z/OS nodes and one for non-z/OS nodes. A DefaultNodeGroup is automatically created based on the deployment manager platform. This node group contains the deployment manager and any new nodes with the same platform type.

Cells
A cell is a grouping of nodes into a single administrative domain. In the Base and Express configurations, a cell contains one node. That node might have multiple servers, but the configuration files for each server are stored and maintained individually. In a distributed server configuration, a cell can consist of multiple nodes which are all administered from a single point. The configuration and application files for all nodes in the cell are centralized into a cell master configuration repository.

At the heart of each member of the WebSphere Application Server family is an application server. Each family has essentially the same architectural structure. Although the application server structure for Base and Express is identical, there are differences in licensing terms, the provided development tool, and platform support. With Base and Express, you are limited to stand-alone application servers. Each stand-alone application server provides a fully functional J2EE 1.4 environment. Network Deployment has workload management, scalability, high availability, and central management of multiple application servers.

Express, Base, and Network Deployment all have a single stand-alone server environment. In the stand-alone configuration, each application server acts as a unique entity. An application server runs one or more J2EE applications and provides the services required to run those applications.Multiple stand-alone application servers can be run on one machine, either through independent installations or through multiple configurations of one installation. However, WAS does not have common management or administration for multiple application servers. Stand-alone application servers do not have workload management or failover functions.

Network Deployment builds a distributed configuration, enabling central administration, workload management, and failover. It integrates one or more application servers into a cell managed by a deployment manager. Application servers can be on the same machine as the deployment manager or on separate machines.Administration and management are handled centrally from the administration interfaces through the deployment manager. Multiple application servers can be createtd to run sets of applications and then manage them from a central location. Application servers can be clustered to allow for workload management and failover capabilities.

Profiles
Profiles were introduced with WebSphere Application Server V6. After installation, profiles need to be defined to have a functional system. Core product files are shared among the runtime components defined by profiles.

System Management
WAS system management uses Java Management Extensions (JMX), allowing users of WAS to buy third-party management tools. WebSphere Application Server provides managed objects (MOs) defined by the JSR-77 specification.