Virtualization and WebSphere Virtual Enterprise

By configuring application infrastructure virtualization in WebSphere® Virtual Enterprise, you can pool together resources that are normally kept separate to accommodate the fluctuations of workload in your environment and increase the quality of service. You can also use application infrastructure virtualization with server virtualization capabilities that are provided by the physical hardware on which the product is hosted.

Application infrastructure virtualization

With application infrastructure virtualization, you can separate applications from the physical infrastructure on which they are hosted. Workloads can then be dynamically placed and migrated across a pool of application server resources, which allows the infrastructure to dynamically adapt and respond to business needs. Requests are prioritized and intelligently routed to respond to the most critical applications and users.

Typically, applications and Java Platform, Enterprise Edition (Java EE) resources are statically bound to a specific server. Some of these applications might experience periodic increases in load that last a short time. The most costly time for an application to become unavailable is during a period of high demand. You must build your IT infrastructures to be able to accommodate these peaks. During the majority of time when your systems experience normal load, a large percentage of your computing capacity might go unused, making inefficient use of IT investments.

In a static environment, applications often span multiple enterprise archives (.ear files), and are not comprehensively defined so that the application can be portable between environments. Statically deployed applications rely on information that is found in the server to which they are deployed.

In the virtualized dynamic operations environment of WebSphere Virtual Enterprise, the static relationship is replaced with a dynamic relationship with looser coupling of applications or resources and server instances. Instead of statically binding applications to servers or clusters, you deploy applications to dynamic clusters, which are application deployment targets that can expand and contract depending on the workload in your environment.

After you deploy your applications to be mobile by using dynamic clusters, the placement of the applications is determined by the operational policies that you define. Autonomic managers control the placement of the server instances and how workload is routed for each application. If workload increases for a specific application, the number of server instances for the dynamic cluster that is hosting the application can increase, using available resources from other applications that are not experiencing increased workload.

Application infrastructure virtualization benefits:

Application infrastructure virtualization example

Figure 1. Application infrastructure virtualization in a Virtual Enterprise environment. You deploy an application to a dynamic cluster that has a specified membership policy or node group. You do not deploy your applications to specific application servers. Instead, the application placement controller (APC) starts application server instances for your dynamic cluster based on the settings that you chose for the dynamic cluster.
With application infrastructure virtualization, the ODR routes to servers that are defined in a dynamic cluster. The nodes that belong to a dynamic cluster are based on a node group or membership policy. This deployment is dynamic because new servers can start on nodes.
Figure 2. The starting of an additional application server to react to changes in application load. Additional application servers can start on the nodes that are selected by your dynamic cluster membership policy to handle additional requests that are coming in for the application.
If workload increases for a specific application, the number of server instances for the dynamic cluster that is hosting the application can increase, using available resources from other applications that are not experiencing increased workload.

Server virtualization

While WebSphere Virtual Enterprise provides virtualization of applications in your environment, you can also deploy the product on virtualized hardware, such as ESX servers, to take advantage of the capabilities provided by the hosting environment.

Server virtualization benefits:

Virtual Enterprise in an environment with server virtualization

WebSphere Virtual Enterprise can operate in supported virtualized server environments. Different server vendors provide different virtualization capabilities, so the behavior of the product can vary in different server virtualization environments. However, common themes exist in server virtualization environments, such as the ability to share server resources across the virtual servers or logical partitions. Server virtualization environments can run in shared processor mode or dedicated processor mode. When you use shared processor mode, the physical processors are pooled and shared between the servers or logical partitions that are running on the physical computer. When you use dedicated processor mode, the physical processors are statically assigned to each virtual server or logical partition.

Figure 3. Shared processor mode. In shared processor mode, the physical processors are pooled and shared among the virtual servers or logical partitions.With shared processor mode, a physical server contains a shared processor pool that is used to run multiple virtual servers or logical partitions, which can contain nodes and application servers.
Figure 4. Dedicated processor mode. In dedicated processor mode, the physical processors are statically assigned to each virtual server or logical partition.
With dedicated processor mode, physical processors are mapped to specific virtual servers or logical partitions. These virtual servers or logical partitions can run nodes and application servers.
Virtual Enterprise can also run in server virtualization environments with dedicated processor mode. The processor capacity is statically fixed to each virtual server or logical partition. The capacity and assignment do not change dynamically. Because the processor resource does not change for each virtual server or logical partition, using dedicated processor mode does not affect the traffic management and virtualization features of the product.
Figure 5. Coexistence of application infrastructure and server virtualization.
Application infrastructure and server virtualization coexistence

On demand router in an environment with server virtualization

The on demand router (ODR) should never be constrained by either CPU or memory usage. Therefore, when you install the ODR in an environment with server virtualization, configure the virtual machine or LPAR in which the ODR runs in dedicated processor mode, or configure it in a mode that guarantees the ODR receives a sufficient amount of CPU resources and dedicated memory when the ODR runs.


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