Cloud computing architecture

With the launch of the Oracle Cloud PaaS Platforms we will make the SOA & BPM Partner Community cloud ready. In this article series we will lay the foundation for cloud computing including definition and concepts.

Concepts in Cloud Computing

Industry focus & use case Cloud Computing Providers & Consumers

Differences between Cloud Definitions

NIST Cloud Computing Reference Architecture

Cloud Broker

Types Cloud Broker

Challenges Cloud Broker

Cloud Computing Hype Introduction

Why is everyone talking about cloud computing? Drawn-out, expensive IT projects that are planned and implemented with few benefits for the business stakeholders are commonplace. In contrast, cloud computing offers business users the chance to immediately implement services with usage-based billing that are tailored to their requirements, often without the need to consult with the IT department.

However, aspects including security, architecture, availability, and standards are often not evaluated. Cloud consumers find themselves at the mercy of the cloud provider. Scenarios that require changing cloud providers after a cloud provider goes bankrupt, and the associated moving of data and/or applications, have not yet been sufficiently tested. Business continuity should play a key role from the start of a cloud evaluation process.

One of the greatest challenges here is the integration of existing data and systems into the cloud solution. Without integration spanning clouds and on premise systems, processes can only be executed in isolation, leading to cloud-specific silos of isolated solutions. Important information for users is not available across processes and systems. Problems that would have occurred in the company's internal IT are now shifted to the cloud provider. To prevent "legacy clouds" or solutions that are hard to maintain, it is important to manage the entire architecture proactively and, in particular, the integration into the cloud. Even if cloud providers want us to believe otherwise, not every aspect of IT can be outsourced to cloud solutions!

Cloud Computing Definition and Criteria

Cloud computing is a model for usage-based network access to a common pool of configurable computing resources (e.g. networks, servers, storage systems, applications, and services) that can be provided and used quickly. IP-based services are requested via self-service and used online independently. A prerequisite for this is a broadband Internet connection with low latency. The IT resources are bundled into pools and provided as required. Billing is based on the services used. *1

Concepts in Cloud Computing

In cloud computing, the following models are differentiated on the basis of horizontal scaling:

· Infrastructure-as-a-Service (IaaS) - provides a hardware platform as a service, such as Amazon EC2 or Oracle Compute Service (now in preview)

· Platform-as-a-Service (PaaS) - provides a software platform as a service, such as Google Apps Engine or Oracle Java Cloud

· Software-as-a-Service (SaaS) - allows applications and functions to be outsourced by virtualizing cloud providers' hardware and software and providing the functions as services, such as Salesforce CRM [REF-1] or Oracle Sales Cloud

In deployment models, distinctions are made according to availability and installation location. Public clouds are services that are available to the public on the Internet. Private clouds are internal company services. Hybrid clouds and community clouds represent mixtures of these

models, such as when Amazon computing power is used in the event of a failure or overload of an internal company cloud application.

Industry focus & use case Cloud Computing Providers & Consumers

Large companies for which IT plays a central role or represents a competitive advantage often build internal company cloud solutions in their own data centers “private clouds”. Small and medium enterprises frequently use public cloud services. A further distinguishing feature is the cloud consumer focus. In the business-to-business segment, private clouds are predominantly used, while in the business-to-consumer segment the majority are public clouds ( Figure: 1).

Differences between Cloud Definitions

Thomas Erl, Ricardo Puttini and Zaigham Mahmood define cloud computing in his latest book “Cloud Computing Concepts, Technology & Architecture”. Based on the NIST cloud computing definition they add “ubiquitous access” as a cloud characteristic, to reflect the trend that more and more services are used on mobile devices. As cloud computing becomes more and more adopted also in b2b services, companies run mission critical applications on a global level in the cloud, resiliency of this services becomes important. Therefore Thomas Erl Ricardo Puttini and Zaigham Mahmood add also “resiliency” to the cloud characteristics.*2

Wikipedia defined cloud computing more from a consumer perspective. The article highlights that cloud computing is often used as a jargon term without a commonly accepted non-ambiguous scientific or technical definition.*3. From my perspective the NIST definition is widely accepted between b2b vendors. Many software vendors try to brand their solutions as cloud solution, or cloud enabled solutions without to respect the NIST cloud definition. This reflects the change of the IT industry caused by cloud computing.

NIST Cloud Computing Reference Architecture

Together with the “The NIST Cloud Definition of Cloud Computing” the “NIST Cloud Computing Reference Architecture” lays the theoretical foundation of cloud computing. The NIST Cloud Computing Reference Architecture extends the definition by a reference architecture and a taxonomy. An additional actor and role model is introduced. The cloud provider offers IaaS, PaaS or SaaS services to the cloud consumer. Between them a cloud broker might offer service intermediation, service aggregation and service arbitrage. These services become more important as cloud services need to be integrated with on premise and integrated or exchanged between different cloud providers. A cloud carrier transports the cloud services from the cloud provider to the cloud consumer. A cloud auditor might support the cloud consumer and cloud provider in security, privacy impact and performance audits*4

Cloud Broker

NIST and Gartner define three different types of cloud brokers:

Service Intermediation

Provides value added services on top of a cloud platform. An example is the Force identity service from Salesforce. This identity service can be used to identify users across several cloud services.

Service Aggregation

Ensures the interoperability between different cloud services. An example is Boomi from Dell. The service let cloud consumers integrate for example a Salesforce CRM system with a Netleger billing system and or an on premise solution. As IT System are often historical grown and rally build on a green field approach cloud aggregation becomes key for cloud adoption.

Service Arbitration

A cloud service arbitrage provides flexibility and an “opportunistic choices”

Category: Architecture

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