Cloud Services Foundation Reference Architecture - Overview

Published:  June 20, 2013
Version:  1.0
Abstract: This article provides an overview of the Cloud Services Foundation Reference Architecture article set. The article set details the operational processes and technical capabilities that are critical for providing cloud services to consumers. 

Table of Contents

1.0 Introduction
2.0 Background
3.0 Reference Architecture
4.0 Cloud Services Foundation
5.0 Summary

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1.0  Introduction

Effectively solving any problem requires fully understanding it, having a clearly-defined approach to solving it, and using previous knowledge and experience to avoid costly mistakes that others have already made trying to solve the same problem. The Cloud Services Foundation Reference Architecture (CSFRA) article set includes guidance that helps you fully understand the processes and technical capabilities required to provide cloud services to your consumers.  This article provides the background for why the CSFRA was created, defines the terms  cloud services foundation  and  reference architecture , and lists the articles included in the article set.

1.1  Included Articles

This article is one of several articles that are included in the Cloud Services Foundation Reference Architecture (CSFRA) article set.  Article sets include multiple articles that are expected to be collectively read, like the chapters of a book.  

The Cloud Services Foundation Reference Architecture article set includes the articles listed below.   

  1. Overview   (this article) :  This article introduces the cloud services foundation problem domain, the article set and its audience, and the articles included in the article set.

  2. Cloud Services Foundation Reference Model (CSFRM): This article defines common terminology for the cloud services foundation problem domain, which includes various subdomains that encompass the minimum set of operational processes, vendor-agnostic technical capabilities, and relationships between the two that are necessary to provide services with cloud characteristics. We recommend that you read this article before you read other articles in the article set, because the terminology in it is used in the remaining articles.

  3. Principles, Concepts, and Patterns: This article defines:

    • Principles: Enduring, rarely amended, and inform and support the way a cloud services foundation fulfills its purpose. They strive to be compelling and inspirational. These principles are often interdependent and together can be applied to the reference model to create a physical implementation.
    • Concepts: Abstractions or strategies that support the principles and facilitate the composition of a cloud services foundation. They are guided by one or more of the principles and directly support them.
    • Patterns: Specific, reusable ideas that have proven to resolve commonly occurring problems. They enable the concepts and principles.

    The principles, concepts, and patterns together form the strategic basis for developing any cloud services foundation. These principles, concepts, and patterns exist across multiple providers of cloud services.

1.2  Audience

The primary audience for the Cloud Services Foundation Reference Architecture (CSFRA) is anyone in an organization who has any of the following responsibilities:

  • To design new or modify existing technical capabilities that are aggregated to provide cloud services
  • To design IaaS, PaaS, or SaaS cloud services that are deployed in in the private, public, community, or hybrid cloud deployment models.
  • To design operational processes that support cloud services

Although the articles in the article set are primarily written for members of an enterprise IT organization that typically provide services to their consumers in the private and hybrid cloud deployment models, most of the guidance is equally applicable to members of an organization that also provide services to their consumers in the public cloud deployment model, such as hosting service providers.

Guidance for implementers that want to implement the cloud services foundation with Microsoft products and technologies can be found at the Microsoft Cloud and Datacenter Solutions Hub.

2.0  Background

From end-users self-provisioning a new email account with the Microsoft e-mail service, to information technology (IT) professionals self-provisioning new virtual machines with the Windows Azure Virtual Machines service, most everyone has experienced how quickly and easily they can start utilizing new IT functionality from public cloud service providers such as Microsoft. As a result, most people have come to expect all of the IT functionality they consume to be as quick and easy to begin using, regardless of who provides the functionality to them.

When most people go to work each day however, they find that their ability to begin using new IT functionality is often much slower and more difficult than it is when consuming similar functionality from a public cloud services provider. This is because most IT organizations were not created to provide IT functionality with fast and easy self-service and the levels of automation that enable it. While many IT organizations understand the benefits of providing IT functionality to their users with similar levels of simplicity and speed as public cloud service providers, they realize that doing so may require significant changes to organizational structures, operational processes, technical skills, and technologies deployed, but they aren’t quite sure where to begin.

The Cloud Services Foundation Reference Architecture (CSFRA) article set was created to help IT organizations start addressing some of the necessary changes. It includes guidance that helps IT organizations understand the vendor-agnostic technical capabilities and operational processes required to deliver IT services with the ease, speed, and “cloud” characteristics that most consumers now expect from all IT functionality that they consume. The guidance also helps organizations understand how they can integrate functionality provided by public cloud services with their own on-premises functionality. This is the new reality for IT organizations; providing both private cloud services to their consumers and integrating functionality from public cloud services providers to provide hybrid cloud services to their consumers.

3.0  Reference Architecture

The term reference architecture means different things to most people that use it. In this article and the article set that it is part of, the term means: A set of words, definitions, relationships, principles, and best practices for a problem domain. Reference architectures are typically created with information that is collected across multiple implementations of solutions in the problem domain for which they’re created. As a result, they often help decrease the amount of costly errors that people who implement solutions in the problem domain might otherwise make.

Reference architectures for a problem domain can be created at any level of detail, from conceptual to physical. The reference architecture that is defined in this article set is conceptual, but it can be used as a foundation for creating physical architectures. The problem domain for which this reference architecture was created is: cloud services foundation.


4.0  Cloud Services Foundation

The word cloud also means different things to most people that use it. This article set uses the following terms from The NIST Definition of Cloud Computing:

  • Essential characteristics: on-demand self-service, broad network access, resource pooling, rapid elasticity, and measured service.
  • Service models: infrastructure as a service (IaaS), platform as a service (PaaS), and software as a service (SaaS)
  • Deployment models: private cloud, public cloud, community cloud, and hybrid cloud

These terms are used commonly throughout the information technology (IT) industry and aren’t redefined in this article, but the terms are used in all articles contained in the Cloud Services Foundation Reference Architecture article set.

To understand the purpose of the Cloud Services Foundation Reference Architecture article set, it’s important to first define the words cloudservices, and foundation, as they’re used in this article set.


Services refer to information technology (IT) functionality that is exposed to a consumer, as the consumer perceives the functionality. A virtual machine service may be provided to a consumer that works in an IT department. Email, inventory ordering, billing, and other services may be provided to end-user consumers within an organization. Services are provided to consumers by aggregating the functionality provided by multiple technical capabilities. Technical capabilities are provided by hardware devices and software applications. Services are provided to consumers with a service level agreement (SLA) that often includes metrics such as availability and performance. The figure below shows a basic virtual machine service that includes six technical capabilities: Compute, a virtualization capability that provides virtual machines, network, storage, service monitoring, and service reporting, to monitor and report actual availability levels against the SLA metrics.


Most IT services typically aggregate many more technical capabilities than the basic virtual machine service shown in the figure above. An organization that provides this basic virtual machine service might describe it as follows:

The virtual machine service provides virtual machines to consumers that request them. After the virtual machine is created, the consumer can connect remotely to the running virtual machine and is responsible for all maintenance of the operating system and applications that run on the virtual machine. This service is provided with a 99.9 percent SLA that is calculated monthly, so in an average month of 30 days, there are less than 42 minutes of both planned and unplanned downtime. Availability is calculated only while the virtual machine is running. This is because the consumer can choose to put the virtual machine into a saved state themselves, which would not count against the SLA.

With an SLA is defined in this way, it means that the service does not meet its availability SLA if either of the following conditions occurred:

  • The network and compute and storage technical capabilities were each unavailable for fifteen minutes, for any reason, at different times during the same month, because collectively, the service would have been unavailable for more than 42 minutes.
  • Any of the individual technical capabilities were unavailable for more than 42 minutes, because the service would have been unavailable for 42 minutes.

This is a key value of services to the consumer, versus individual technical capabilities. Consumers are not concerned about what caused the service to be unavailable, only whether it met its SLA each month. Aggregating technical capabilities and providing them as services to consumers is certainly not a new concept. Over time, several different IT service management (ITSM) frameworks have been created to help organizations define operational processes that enable them to provide technical capabilities as services.

Transitioning from providing technical capabilities to providing services to consumers is a major undertaking for many organizations however. It often requires significant changes in organizational structures, in the technical capabilities that are used in the organization and how they’re used, and in the operational processes that are used in the organization. Microsoft documented the transition to providing services to consumers in the article Software to Services - A Journey by Microsoft, which includes valuable insight into what kinds of changes are required. Some organizations choose not to make this transition; many other organizations are in the process of making the transition, while others have successfully completed the transition. Successfully transitioning to providing services often requires commitment from senior executives within an organization.

While many organizations find it valuable to provide services to their consumers, services can be provided with various characteristics.


The word cloud is used to represent a specific set of service characteristics. To illustrate cloud characteristics, consider the Windows Azure Virtual Machines public cloud IaaS service that Microsoft provides for its consumers. The functionalitySLA, and pricing information for the service are all published on the Microsoft website. The service provides all of the NIST essential characteristics:

  • On-demand self-service: Any consumer, by using a web browser at any time, can go to the Windows Azure website, create or sign in with an existing Microsoft account, set up a subscription with billing information, and begin creating virtual machines with different memory, processor, and storage configurations, and by using various operating systems. The whole process, from setting up an account to connecting and running a virtual machine, takes less than an hour.
  • Broad network access: Any user can access the Windows Azure Virtual Machines service over the Internet with a web browser on multiple types of devices.
  • Resource pooling: Although the consumer doesn’t necessarily know it, Microsoft provides the service to the general public on pooled resources that consist of thousands of servers and massive amounts of storage. Since data security is critical when providing services with pooled resources, Microsoft describes how it keeps customer data secure in its Windows Azure Trust Center.
  • Rapid elasticity: Consumers can add new or remove existing virtual machines when and as often as they like.
  • Measured service: At any time, consumers can sign in to the Windows Azure Management Portal to view their billing information for each month. They’re billed only for the resources that they use. The amount is based on the published pricing information.

To provide services with cloud characteristics, you might require additional technical capabilities beyond those that you use to provide services without cloud characteristics today. For example, to provide the basic virtual machine service shown in the figure aboveas a service with cloud characteristics, you’d also require the following additional technical capabilities:

  • Consumer portal: This enables the on-demand self-service characteristic
  • Usage and billing: This enables the measured service characteristic
  • Process automation: Automation is a key enabler for both the rapid elasticity and on-demand self-service characteristics

Further, you might require additional operational processes or different operational processes than you use today to provide services without cloud characteristics.


The word foundation represents the minimum operational processes, and technical capabilities that are necessary to provide any services that exhibit cloud characteristics, but it does not represent the services themselves. Each service that you provide might require unique combinations of the foundational technical capabilities, unique operational processes, or both. Further, each service that you provide might require you to add additional technical capabilities to the foundational capabilities. You may provide a service to your consumers with technical capabilities that you manage. This is often referred to as providing a service in a private cloud deployment model. You may provide a service to your consumers with technical capabilities managed by an external provider. This is often referred to as a providing a service in a hybrid cloud deployment model.

The Cloud Services Foundation article set provides guidance that helps you establish a cloud services foundation.


5.0  Summary

This article introduced the cloud services foundation problem domain and the Cloud Services Foundation Reference Architecture article set. We recommend that you read the Cloud Services Foundation Reference Model article next because it contains the terminology that is used throughout the remainder of the articles in the article set. For additional architectural and solutions content, please visit the Cloud and Datacenter Solutions Hub.

6.0  Change Log


Version Date Change Description
1.0 6/20/2013 Initial posting and editing.