Getting Your Arms Around SOA Virtually

While business operations have raced ahead at Internet speed with the support of state-of-the-art applications development, IT manages change as a series of unique one-time events. This is troubling at a time when three-tier—web, application, database—composite applications built with Java™ 2 Platform Enterprise Edition (J2EE) servers, such as IBM WebSphere® Application Server, are the norm for high-end business applications of consequence. What's more, the next step in software evolution, the adoption of a Service Oriented Architecture (SOA) (link resides outside of ibm.com), ties composite applications to business processes, and that makes the health of these applications increasingly important. Enterprise Workload Manager (EWLM) is IBM's solution to managing these complex applications easily from end-to-end.

J2EE applications typically run in highly heterogeneous environments with multiple types of servers, middleware, and multiple operating systems. Supporting such an application throughout its lifecycle presents a daunting challenge to any IT shop. Adding to the challenge, a composite application exists as an integrated whole only at the instance when a user interacts with it. That means the health of any one component at any particular instance will reveal little about the application; rather, user perception of the application is entirely determined by how the modules come together. More importantly, how the modules come together is determined by the status of the entire environment.

Virtual Unified Infrastructure
Adding fuel to the fire of support challenges, no preproduction test environment can cover all of the complexity of the final production environment in which the application will be deployed. That makes lifecycle support a constant task of gathering detailed statistics about what is happening within the production environment. To answer that challenge, Enterprise Workload Manager is a key component of the IBM Systems Director solution, designed to dynamically monitor and manage distributed workloads in heterogeneous environments based on well-defined business goals.

EWLM virtualizes servers into a logical group dubbed the EWLM management domain, which can then be managed as a logical entity. In particular, EWLM enables IT operations managers to define EWLM domains that encompass all of the servers in the domain of a three-tier composite application.

"Enterprise Workload Manager (EWLM) is a key component of the IBM Systems Director solution, designed to dynamically monitor and manage distributed workloads in heterogeneous environments based on well-defined business goals."

In such a management domain, an EWLM server facility called the EWLM domain manager can gather and report performance data from each server, application, and process via agent software installed on each managed server. The EWLM domain manager collects this data every 10 seconds and can then send load balancing commands to load balancing switches from Cisco Systems or Nortel Networks. With 10-second granularity, the domain server can readily adjust the load balancers for bursty processing requests. In addition, the EWLM manager can also dynamically manage the resources assigned to a logical partition (LPAR) associated with a POWER® Hypervisor. Visitors to the web sites of the four Tennis Grand Slam events, which featured live audio and video feeds this year, along with the stroke-by-stroke Point Tracker, had their web experience enhanced by EWLM.

Armed for Performance Monitoring
Systems administrators interact with the domain manager through a browser-based user interface dubbed the EWLM control center. The EWLM control center runs as an instance of the WebSphere Application Server included in the System's Director common runtime.

The mechanism that enables the response time measurement of each server is the Application Response Measurement (ARM) (link resides outside of ibm.com). Key applications, including WebSphere, DB2 Universal Database, Apache, and Microsoft® Internet Information Services (IIS), are already enabled for ARM. What's more, IBM offers free Build to Manage (BtM) toolkits that enable in-house and commercial developers to readily incorporate standard management interfaces, including ARM, into their applications. Such instrumentation enables data collection explicit to the application.

Business Rules
The most important aspect of the end-to-end data collection and autonomic management performed by EWLM is that it is all done with respect to business processing goals via service policies. One of four types of performance goals can be set for a service class: percentile response time, average response time, velocity, and discretionary.

The percentile response time goal indicates what percentile of transactions should be completed in a specified amount of time. The average response time goal identifies the average amount of time in which work in the service class should be completed. Applications for which a response time goal is not appropriate can be assigned a velocity goal. Such a goal defines how fast work should run without delays due to processor constraints, storage problems, and I/O delays. EWLM uses CPU utilization, storage, and IO delay statistics for this evaluation. Finally, processes that can be delayed and processed when spare system resources are available can be classified as discretionary.

The benefits derived by managing composite applications with a solution such as EWLM can have a significant impact on service-oriented business initiatives. EWLM enables administrators to assure the availability and performance of critical composite business applications and services by comprehensively monitoring the end-to-end performance of transactions and the health of the resources that support those transactions. What's more, EWLM's autonomic management features think like a business manger. Using service-level objectives established for your business applications, EWLM learns the relationships between the servers, the application middleware, and business processes. The bottom line for the CIO is an understanding of performance bottlenecks as they relate to specific business performance goals.