Industry News Desk
Cloud Computing: A Transition Methodology
Roadmap to the Cloud
By: Rod Fontecilla
Apr. 13, 2009 10:45 AM
Cloud computing refers to the practice of leveraging third-party computing resources, such as network grids and server farms, to extend IT capabilities and reduce the cost of ownership. This practice offers numerous potential benefits to organizations that want to centralize software and data storage management while eliminating the costly overhead of in-house hardware and software maintenance and the personnel required to build, support, and maintain enterprise computing solutions.
Cloud computing has emerged as a new computing paradigm that gathers massive numbers of computers in centralized data centers to deliver Web-based applications, application platforms, and services via a utility model. The primary difference between the service models of cloud computing and previous software (e.g., outsourcing or data center consolidation) is scale. The premise is that as the scale of the cloud infrastructure increases, the incremental time and cost of application delivery trends toward zero.
Cloud computing allows users to dynamically and remotely control processing, memory, data storage, network bandwidth, and specialized business services from pools of resources, providing the ability to specify and deploy computing capacity on-demand. If there's a need to scale up to accommodate sudden demand, users can add the necessary resources using a Web browser. The large data center can provide similar services to multiple external customers (multi-tenancy), leveraging its shared resources to increase economies of scale and reducing service costs.
Although cloud computing is in its early stages and definitions vary greatly, the underlying technologies today are consistent. These technologies include the following:
There are a number of service offerings and implementation models under the cloud computing umbrella, each with associated pros and cons. These models can be grouped into the following three categories: Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS), and Software-as-a-Service (SaaS). These models target varying levels of services, ranging from general infrastructure services, such as operating systems or database services provided by IaaS vendors to targeted functional services provided by SaaS vendors (e.g., customer relationship management from Salesforce.com).
The various players in the current market can be differentiated into the following two categories:
We recognize that the transition to a cloud computing paradigm presents a number of challenges. Issues associated with information security, reliability, and service level agreements challenge mission-critical systems. Furthermore, we've identified what we consider the key characteristics of a cloud computing environment:
My experience has emphasized the importance of "architecting for the cloud" versus simply deploying system components to the cloud to ensure that business requirements are met. Typical software and systems that are not designed to take advantage of the scalability and parallelism of the cloud will likely not achieve the full benefit that is provided by a cloud computing environment. It's also highlighted the need to transition the role of IT managers to brokers and negotiators of IT services rather than the day-to-day management of the operating platform.
My analysis of the benefits and challenges presented by the cloud computing paradigm has resulted in the identification of the following three cloud variations:
Though many cloud providers proclaim that moving existing applications to the cloud is seamless and doesn't require code changes, my experience has shown that greater analysis and re-engineering are required to achieve the full benefits of a cloud computing environment. Complexities remain that organizations must consider when moving to the cloud, and careful planning is essential.
Based on the lessons learned from previous efforts, a phased Cloud Computing Transition Methodology designed to address the issues and risks associated with migrating an existing system to the cloud is developed. Figure 1 provides an overview of this approach.
The Cloud Strategy and Planning phase (Phase 1) consists of three steps designed to ensure that all aspects of moving to a cloud environment have been appropriately evaluated and agreed upon. The three steps are:
1. Conduct a Strategic Diagnostic
The primary areas to be addressed during the diagnostic step are security and privacy, technical, business and customer impact, economics, and governance and policy. We will evaluate the implications of moving to the cloud environment in each of these categories and document the key issues and considerations revealed during the diagnostic step. The outcome of this diagnostic will be sufficient analysis to support a "go/no go" decision to move to a cloud computing environment and the development of an agreed-on cloud strategy.
2. Define a Cloud Strategy
3. Create an Implementation Plan
After completing Phase 1, the organization will have fully analyzed its options, identified all requirements, thoroughly assessed short-term and long-term costs and benefits, gained executive governance approval, and socialized the solution with stakeholders (including oversight entities). This phase ensures that the organization will have a high degree of confidence in successfully moving to the cloud environment, reap the expected benefits, not constrain future functionality, and avoid hidden future costs.
The Cloud Deployment phase (Phase 2) focuses on implementing the strategy developed in the planning phase. Leveraging the various cloud models helps identify the most effective solution(s) based on the existing organization architecture. Some of the criteria used in recommending a vendor are the vendor's primary service model (i.e., infrastructure, platform, or software), business model, how much existing technology can they leverage, end-user experience, and risks involved in porting to the cloud. Deploying to the cloud involves taking the decision analysis from Phase 1 as input and proceeding with the following four steps:
1. Assess/Select the Cloud Provider(s)
The assessment step captures three important inputs: the current organization technical architecture, objectives, and the vendor selection criteria that are tailored to meet the organizational objectives. The vendor assessment results in recommendations on the most appropriate cloud vendor, assists in selecting the most effective cloud model, develops deployment strategies, highlights reusable components, and identifies the security options for the cloud architecture.
2. Establish Service Level Agreements (SLAs)
A typical SLA will identify service levels for the following:
3. Execute Transition
4. O&M and Help Desk
Deploying cloud computing solutions requires both a short-term and a long-term strategy. For example, besides the improved scalability and reliability provided by the cloud, which organizations may achieve through the initial transition, re-engineering some components to take advantage of the parallelism provided by the cloud could improve system performance and overall scalability further. Transitioning an existing system to the cloud requires an approach that addresses not only the technical aspects of cloud computing but also considers the objectives of the organization, the constraints imposed by the existing system, and the impact to its existing customers. As an experienced cloud computing strategist, I believe that corporations and even the government sector are prepared to consider the complexities of cloud computing technologies.
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