Article by Chandrashekhar P. More

The business services implemented using the Service Oriented Architecture ( SOA ) and deployed on the “Plug and Play” and the “Pay for you use” infrastructure service of the cloud computing platform will benefits both Business and IT .

In this article, I will provide a cursory walkthrough to demonstrate how the Service Oriented Architecture can be used with the cloud computing platform.

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Scenario Background

The XYZ Company is a nationwide grocery chain. The company uses the internet kiosk for their retail transactions. Each store has the store server computer installed.

The company

	has to go through laborious server upgrade process
	has to deal with the frequent server outages during the shopping season
	has issues during the addition of new items in the inventory and promotions updates - so business wants to improve the Catalog management process

Define Service Oriented Architecture

Identifying the right service is a key for the service oriented architecture development process. The identified services needs to be well defined, self-contained and should encapsulate the business functionality.

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The following section explain the different services layers mapped to the high level business architecture component for the XYZ company:

1. Store Services layer

The store services layer are pluggable store services that can be added as XYZ company adds new stores or removed when company decides to close them. Each store will manage its own item inventory and have an ability to collaborate with peer stores, corporate and vendors.

2. Enterprise Services layer

The enterprise services at the XYZ company are the core services that harness the data and the services required for the business intelligence, financial management , billing or payment services, procurement, vendor etc.

3. Vendor Services layer

The vendor services layer interact with the existing external parties that interact with the organization.

The enterprise services interact with the vendor services for the inventory request, capacity data, financial data etc.,

Communication between Services

The business architecture is not complete without modeling the business processes. The BPM tools will help to model these business processes. The enterprise services, vendor services and the store services collaborate with each other by triggering the business process service at each end. A careful consideration needs to be given while defining the interaction between the service to meet the Service Level Agreement.

The couple of scenarios are explained below to demonstrate effective communication.

Scenario 1: Product Pricing and Promotion Service pipeline

For the XYZ company, a process services called as "Product Pricing and Promotion service pipeline" is created to manage the product pricing and the promotion data. The service is located at three layers and have different responsibility based on the layer.

The working of this service is explained below:

1. The XYZ's vendor sends the new pricing and promotion data using the XYZ's "Vendor Product Pricing and Promotion" service
2. The request is authorized and authenticated by the XYZ's vendor services and then it is forwarded to the "Enterprise Product Pricing and Promotion" service.
3. The request in the enterprise service layer is routed to the automated service for the automatic request approval or if the request needs manual intervention, the request is submitted to appropriate approval department
4. After automatic or manual approval, the change request are broadcasted using the notification service to all the subscribers (stores services in the store services layer )

In the "Product Pricing and Promotion " service pipeline, we saw that the business process service can collaborate with each other by invoking another process service or broadcasting the information to the interested subscriber(in example store services) and are constrained by the policies that are enforced automatically or manually.

Scenario 2: Catalog Management Service

The XYZ company has a policy that items will not be added to the store catalog without prior approval from the catalog manager at the enterprise service layer and therefore the catalog management service is available at enterprise service layer and also at the store services layer.

Each catalog manager will add the item in the enterprise database using the service at the enterprise service layer and the item information will be broadcast to the individual stores on the scheduled date to update the store database.

In both the scenario, we saw that the two independent services-Catalog management and Pricing/promotion management services can effectively perform synchronous and asynchronous communication.

Identify the infrastructure required to deploy the services

The services identified in the service oriented architecture can be a single instance or the multiple instances type. The multiple instances type service will be context driven and will require an effective deployment strategy.

For the XYZ company,

- the store services and the vendor services are of the multiple instances type

- the enterprise services are the core services and are the single instances type

- the store service and vendor services should be deployed by location to improve the SLA

The concept of the "Infrastructure as a Service ( IAAS) " can be effectively used for XYZ company. "Infrastructure as a service" is based on the utility computing and provide "Pay as you use" offerings rather than purchasing brand new server and/or network equipment. The Amazon cloud services for example can be used in this situation as it offers an ability to deploy servers based applications on the locations. This will help XYZ company to eliminate the need of the physical store computer and manage the support for frequent outage issue and enabling business to manage the services instead of servers.

Service Governance

As indicated in the last two sections, there are lots of moving parts to service the enterprise. Aligning IT services to the business and managing the policies and contract of the services are key to maintain the integrity of the system, therefore, the service governance now become critical for the implementation and management of the services.