Cloud Reference Architecture
Reference Architecture (RA) provides a blueprint of a to-be-model with a well-defined scope, the requirements it satisfies, and architectural decisions it realizes. By delivering best practices in a standardized, methodical way, an RA ensures consistency and quality across development and delivery projects.

Major players in the cloud computing field are:

• Hewlett Packard
• IBM
• Microsoft (Unlike HP, IBM Microsoft's Cloud Reference Architecture is specific to HYPER-V )

They have created their reference architecture for cloud computing. This should be a very happy news for enterprise adoption as we have blueprints from the industry leaders.  We strive to analyze their reference architecture on how they view the blueprint of a cloud model.

The intention at this time, not to give any opinion on which is better, it is more of a understanding of their point of view.

For the rest of the article, Cloud Computing Reference Architecture is mentioned as (CCRA).

All the materials discussed in this article are taken from the publically available content (Google Search) of the respective vendors.

Service Consumer in CCRA
IBM: Cloud Service Consumer or Client is viewed as ‘In House IT' who can use an array of Cloud integration tools to get the desired business capability. This could be individuals within the enterprise too, however the ‘In house IT' could be a general collection of all of them.

HP: Cloud Service Consumer is represented in ‘Demand' layer of CCRA. However the demand layer covers more than the consumer, but also service catalog, portal access for provision of services. The service provider plays a important role in the Demand layer too, as provider is the one who makes services available as Configure to Order through an automated service system.

Microsoft: The tenant/user self-service layer provides an interface for Hyper-V cloud tenants or authorized users to request, manage, and access services, such as VMs, that are provided by the Hyper-V cloud architecture.

Service Provider in CCRA
IBM: Providers are the ones, who deliver the  Cloud Services to the  clients.  They consist of basic models:

• Infrastructure-as-a-Service
• Platform-as-a-Service
• Software-as-a-Service
• Business-Process-as-a-Service

The providers are also inclusive of existing third-party services and partner eco systems.

HP: Service Providers play their role in both ‘Demand', ‘Deliver' layers of CCRA. In the delivery layer, Service Providers intelligently orchestrates the configuration and activation of services and schedules for the provisioning of the necessary resources by aggregating data from the service configuration model.

Microsoft: Taking a service provider's perspective toward delivering infrastructure transforms the IT approach. If infrastructure is provided as a service, IT can use a shared resource model that makes it possible to achieve economies of scale. This, combined with the other principles, helps the organization to realize greater agility at lower cost. As evident this Reference Architecture concentrates more on IaaS delivery.

Service Creator in CCRA
IBM: Service creator are the ones who use service development tools to develop new cloud services. This includes both the development of runtime artifacts and management-related aspects (e.g., monitoring, metering, provisioning, etc.). "Runtime artifacts" refers to any capability needed for running what is delivered as-a-service by a cloud deployment. Examples are JEE enterprise applications, database schemas, analytics, golden master virtual machine images, etc.

HP: Service creator plays a role in ‘ Supply Layer' which functions as the dynamic resource governor that integrates a dynamic and mixed work load utility function across a heterogeneous environment with a model based orchestration system to optimize the supply of resources to fulfill the delivery of service requests. Again there are templates and tools that support the Service Creator in ‘Supply Layer'.

Microsoft: The orchestration layer must provide the ability to design, test, implement, and monitor these IT workflows. The orchestration layer is the critical interface between the IT organization and its infrastructure and transforms intent into workflow and automation.

Infrastructure in CCRA
IBM: "Infrastructure" represents all infrastructure elements needed on the cloud service provider side, which are needed to provide cloud services. This includes facilities, server, storage, and network resources, how these resources are wired up, placed within a data center, etc. The infrastructure element is purely scoped to the hardware infrastructure.

HP: "Infrastructure" layer is abstracted behind the ‘Supply Layer' and consists of power & cooling, servers , storage, network, Software, information and other external cloud.

Microsoft: "Infrastructure" layer covers, Servers, Storage, Networking, Virtualization.

Management Platform in CCRA
IBM: Cloud management platform consists of Operational Support Services (OSS) and Business Support Services (BSS).

Business Support Services represents the set of business-related services exposed by the Cloud platform, which are needed by Cloud Service Creators to implement a cloud service. Some of them being:

• Customer Account Management
• Service Catalog Offering
• Pricing/Billing/Metering
• Accounts Receivable and Payable

Operational Support Services represents the set of operational management / technical-related services exposed by the cloud platform, which are needed by Cloud Service Creators to implement a cloud service. Some of them being

• Provisioning
• Incident and Problem Management
• Image Life Cycle Management
• Platform and Virtualization Management

HP: Aspects of Cloud Management,  cuts across all the layers of CCRA below are some of the management aspects taken care in each layer (this is not the exhaustive list):

Demand Layer

• User Access Management
• Service Offer Management

Delivery Layer

• Billing and Rating
• Request Processing & Activation

Supply Layer

• Usage Metering
• Dynamic Work Load Management

Microsoft: The management layer consists of the tools and systems that are utilized to deploy and operate the infrastructure. In most cases, this consists of a variety of toolsets for managing hardware, software, and applications. Ideally, all components of the management system would use the automation layer and not introduce their own protocols, scripting languages, or other technologies, because this increases complexity and may require additional staff expertise.

Qos (Quality of Service) in CCRA
IBM: Security, Resiliency, Performance & Consumability are cross-cutting aspects on QoS spanning the hardware infrastructure and Cloud Services. These non-functional aspects must be viewed from an end-to-end perspective including the structure of CCRA by itself, the way the hardware infrastructure is set up (e.g., in terms of isolation, network zoning setup, data center setup for disaster recovery, etc.) and how the cloud services are implemented. The major aspects of QoS being

• Threat and Vulnerability Management
• Data Protection
• Availability & Continuity Management
• Ease of doing business
• Simplified Operations

HP: Much like Cloud Management QoS in CCRA cuts across all the layers of CCRA.

Demand Layer

• Quality Of Experience
• SLA Compliance

Delivery Layer

• Quality Of Service

Supply Layer

• Resource Monitoring and Dynamic allocation

Microsoft: The service management layer provides the means for automating and adapting IT service management best practices.

Summary

Availability of a Reference Architecture by the three leading industry pioneers is a good sign for the enterprises to adopt Cloud Computing based delivery model. As we have seen there is a fair amount of similarities in between which should pave the way for inter-operability and avoid vendor lock in with the cloud applications. The following diagram summarizes the common building blocks in the reference architecture published by the big 3. We also find the Microsoft Reference Architecture covers more physical aspects of a cloud platform.

References

IBM Presentation : Building Your Cloud Using IBM Cloud Computing Reference Architecture

HP Cloud Reference Architecture - HP Software Universe 2010 - Presentation on Slide Share

Microsoft Hyper-V Cloud Reference Architecture White Paper

• Reference Architecture for Cloud Computing
• Big 3's Share of U.S. Market Drops Below 50% for First Time in History, an Industrial Info News Alert
• rPath's take on Cloud Computing: Pragmatic Cloud Adoption
• Cloud Computing Reference Architectures, Models and Frameworks