Introduction to Web Services Management
With the boom in distributed computing, the Internet world is heading towards Services Oriented Technologies. Web Services have become the buzzword of today. Web Services offer easy and standardized communication for loosely coupled and dynamically discovered software components over the Internet. Enterprises have started experimenting with Web Services at their corporate intranets before actually going live to their customers over the Web.
Being distributed and dynamic in nature, Web Services need to be managed with care.
In the forthcoming articles, we will discuss each one of the components of WSM in detail and propose implementation architectures for them.
What Are Web Services?
Even if the technologies such as CORBA and COM introduced the services-oriented distributed concepts, they could never become the universal choice of enterprises and developers. In search of standardization and simplicity, e-business technologists and customers looked forward for a loosely coupled and dynamically discovered services technology, which is known as Web Services. These services are software components developed by their vendors to solve some business problems. These services can reside on different systems and can be implemented by vastly different technologies, but they are packaged and transported using standard Web protocols, such as XML and HTTP, thus making them easily accessible by any user on the Web. Web Services Technology has become a key to the Service Oriented Internet World in a very short time period because it promises the interaction of unknown and unrelated applications on the Internet in a more standardized and simpler way than any other approach ever claimed.
Why Manage Web Services?
After understanding the nature of Web Services, we can see their deployment scenarios where the following four players have vital roles to play:
- Web Services Provider (WSP)—This is the entity (for example, a business organization) that designs and develops Web Services.
- Web Services Infrastructure Provider (WSIP)—This entity provides the infrastructure services to deploy Web Services at its premises.
- Web Services Broker (WSB)—Broker has the information of Web Services hosted by WSIP or WSP in the Web Services registries.
- Web Services Client (WSC)—Clients are actual consumers (or, end-users or applications) of Web Services.
Web Services can be deployed in various fashions and on different platforms. This strongly urges a need to manage them in a centralized sphere of control depicted by Figure 1:
Figure 1: Web Services Management—Control Sphere
Note: The direction of the arrows shown in Figure 1 is the direction of the flow of requests initiated by Web Service Clients. Consider an example of this flow: WSC requests WSB to provide the information of a registered Web Service. After getting the response, WSC invokes the Web Service provided by WSP and hosted by WSIP. This flow depends on the design and deployment of Web Services in a business scenario.
The previously-discussed four players (shown in Figure 1) may or may not play a role in the control sphere. Their participation depends upon the Web Services deployment configuration/fashion. This control sphere is also referred as the heart of the Web Services Management Platform (referred to as WSMP hereafter).
Digging into the complexity of business in the present world, there are many development and deployment scenarios possible for Web Services. These scenarios, when needed to interoperate, create more complicated systems. If these systems are not operated carefully, they may hinder the advantages of Web Services. To have control over the above-mentioned complexity of the heart of WSMP, we must have a wrapper of management services over it. This wrapper is responsible for managing Web Services and the four players, which are operating in the heart of WSMP.
The primary goal of enterprises that are currently using Web Services is to derive a business sense out of this technology and drive their strategies based on that. This can only be done when they have proper control over Web Services offered to their customers. This control can be visualized by some infrastructure services in the above-mentioned Control Sphere. There are many core requirements for Web Services to work in a commercialized world where they can help enterprises get returns for their investments.
When we translate the above-discussed needs into the components of the wrapper over the heart of WSMP, we see these core modules:
- Access Mechanism (Authentication and Authorization)
- Web Services Provisioning (Subscription, SLA, and License (Contract) Management, Monitoring, Metering, and Billing)
- Secure Communications
- Service Virtualization and Workflow Management, and so forth
Web Services Management Sphere
Having discussed the need of various infrastructure components of the WSM Sphere, we will now see that our Sphere looks like this:
Figure 2: Web Services Management Sphere—Core Infrastructure Components
Note: The components shown in the WSM sphere are the core functionality modules identified. Different vendors of the WSM platform may identify more advanced pieces in their WSM sphere.
Now, let us briefly discuss each one of the infrastructure components.
These tools aim to assist:
- Web Services Providers develop their Web Services.
- Web Services Infrastructure Providers deploy the Web Services.
- Web Services Brokers provide Web Services information.
- Web Services Clients invoke Web Services.
The WSM infrastructure should be able to authenticate and authorize Web Services Clients. When a client logs in, a session is created and maintained until he/she logs out of the system. Sessions are used in various other components of WSM as well.
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