|As a final preview of this week's building block sessions in the Enabling cloud computing with WebSphere campaign, I caught up with WebSphere DataPower architect Tim Smith. Tim is delivering a podcast that introduces and explains the new Application Optimization capabilities in the WebSphere DataPower line of products. Here is what Tim had to say:|
|Me: I speak with quite a few customers about the WebSphere CloudBurst Appliance, and for once I'm happy to be the one asking this question. Why do we deliver WebSphere DataPower in the appliance form factor?|
Tim: DataPower has become a dominant player in the DMZ and in the ESB. Much of the reason is that this is a purpose built hardware appliance. There are many things that our customers like about this appliance package. First, it has security as part of its DNA. The basis for securing connections, applies throughout the network whether it is in a DMZ or in an ESB. The physical box provides tamper resistant protection. Another reason is availability -- there are no spinning media, dual power supplies, and a focus on fail over support.
In both the DMZ and the ESB, there has been a proliferation of products. The main reason for the proliferation is that customers want to remove as many decisions from the general purpose server as possible, and let servers do what they do best, process application requests. The devices that have been proliferating make more decisions on the request. They do deep packet processing and routing. They also may transform the request into an entirely different request. So, there are an abundance of "pre-processing" decisions and operations made. With DataPower, many functions are integrated into the single hardware platform, giving you a smaller box count. No need to purchase and maintain several platforms, their OS and software versions, compatibility lists, etc. With a single hardware box that does so many things, we can greatly reduce the total cost of ownership for our users.
The DataPower appliance is a blend of Hardware and firmware that is well provisioned with hardware assists that help compile, parse, and assist in many of the intensive packet processing capabilities. To summarize, you get an extremely flexible and adaptable product that reduces total cost while increasing performance.
|Me: A theme that comes up in cloud computing over and over is consolidation. Can you speak to the consolidation offered by WebSphere DataPower appliances with respect to the self-balancing capabilities?|
|Tim: Yes. My answer to the prior question was a long-winded way of describing DataPower's ability to consolidate many features into a single platform. Self-balancing is an example. As DataPower became more popular, larger installations required multiple DataPower appliances in a tier of platforms. A common architecture was to place a load balancer or IP sprayer in front of the tier to distribute the traffic evenly among the tier of DataPower appliances. An IP sprayer is an example of another platform that needs to be added to the environment. It is another box that must be purchased, managed, and maintained. Self-balancing is a feature that was added to DataPower to eliminate the need for an IP sprayer. The way it works is that one of the DataPower appliances in the tier owns the Virtual IP (VIP) Address. It receives all of the traffic, and then distributes it to each of the other DataPower appliances in the tier. If the DataPower appliance that owns the VIP address goes down, one of the others is elected and it takes over. The result is one less product required to support the same level of functionality.|
|Me: For much of the past, cloud computing mostly focused on virtualization and management of resources at the raw compute level (servers, storage, networking, etc.). While there is definitely ongoing focus here, we start to see it moving up the stack towards applications, and part of that effort includes more evolved application load distribution. With that in mind, how can WebSphere DataPower help users more effectively distribute requests to their applications?|
Tim: If a front end appliance or gateway device can dynamically learn information about its environment, specifically the back end, it will be able to make better decisions on how and where to route the request. This is one of the tasks that the Application Optimization feature addresses. Information from the back end can of course be manually configured, but the real value in cloud computing is dynamically adapting when new server resources are brought on line or are taken off line. In the 3.8.0 release, we implemented something called Intelligent Load Distribution (ILD). Intelligent load distribution focuses on continually learning the topology of a back end, updating DataPower's load balancers with that information, and distributing the load based on the updates. In addition to the topology, ILD learns the weights associated with each server. These weights can continually and automatically change as traffic patterns change. The result is load balancing to the back end that sends the optimal amount of load to each server.
Another traffic distribution aspect incorporated into ILD is session affinity. When a server application needs to receive every request from a given client, session affinity is used to route the requests to the same server. In some sense, session affinity overrides the load balancing algorithm. The session affinity support works with any type of back end server, but with a WebSphere back end, all session affinity information is automatically configured.
|Me: Continuing on the theme of application intelligence, what is this new Application Routing option in WebSphere DataPower?|
Tim: ILD focused on learning the topology of the network and making better decisions based on an ever changing cloud topology. Application Routing does something similar by learning which applications are running on each server. Once a request is handed to DataPower's load balancer, the request is classified as to the application that it is targeted for. Then the request is load balanced amongst the servers that are running that application. The information to perform application routing is dynamically learned and changes as applications are added or removed.
WebSphere has invested substantially in managing the life cycle of an application. Changing from one edition of an application to the next sounds like an easy task, but it can be very difficult to perform this type of maintenance on a production environment. The DataPower appliance supports life cycle management by working with the WebSphere back end to provide group and atomic edition rollout. The rollout feature allows traffic to be gracefully diverted from servers that are being taken offline and reloaded with the new application edition. This rollout can be done while leaving the other applications on the server unaffected. This support makes edition rollout a very simple task for the system administrator.
|Me: Thanks Tim!|
|Tim's WebSphere DataPower podcast, along with others, will be available this week on the Global WebSphere Community website.|
|-- Dustin Amrhein|
A view from the clouds: Cloud computing for developers
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