Hybrid Cloud Architecture: A Primer on the Development Trends

Public cloud computing was once all the rage in the IT world. in 2010, the industry's focus shifted back to private clouds after IT professionals voiced concerns about the security of public clouds. Now, because everyone wants to demand operational flexibility, hybrid clouds are a natural fit.

The results of several recent cloud computing surveys confirm the growing interest in hybrid clouds. 21% of IT organizations are looking at hybrid clouds, according to a Unisys survey conducted in 2010, and the results of a 2010 Sand Hill Group survey of more than 500 IT executives suggest that hybrid cloud usage will triple in the next three years.

Hybrid Cloud Architecture Analysis

So what is a hybrid cloud? For the uninitiated, a hybrid cloud is a combination of at least one private cloud and one public cloud. The private cloud can be an on-premises private cloud or a virtual private cloud located in an enterprise data center. As shown in the figure below, we provide a simple schematic of a hybrid cloud that includes a single on-premises private cloud and a single off-premises public cloud:

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The black circle in the diagram represents the active virtual server image, while the white circle represents the virtual server image that has completed migration using a secure connection. The arrows indicate the direction of the migration. Enterprise users are connected to the cloud using a secure connection, where the secure connection can be a virtual private network (VPN) or a secure HTTP browser.

In theory, a hybrid cloud could also include multiple private and/or public clouds. The enterprise data center in the diagram may include active servers (either virtual or physical) that are not part of the private cloud.

What is driving hybrid cloud computing?

Hybrid clouds have arisen out of a concern to utilize the benefits of both public and private clouds in a seamless manner. But some of the risks associated with public and private clouds are also present in hybrid clouds. The benefits and risks of public, private, and hybrid clouds are listed below:

Benefits of Public Cloud:

Low investment hurdle: pay for what you actually use

Good test/development environment for applications that scale to many servers

Risks of Public Cloud:

Security issues: multi-tenancy and transmission over the Internet

IT organizations may react negatively to loss of control of data center functions

Benefits of private cloud:

No need to focus too much on security because existing data centers are under control

IT organization retains control and management of the data center

Risks of Private Cloud:

High investment risk in private cloud implementation and procurement of new hardware and software

New business processes need to be developed; original processes are not well suited for private cloud

Benefits of Hybrid Cloud:

Operational Flexibility: Run business-critical operations on private cloud, development and testing on public cloud

Elasticity: can run peak and high-volume workloads on public cloud

Risks of Hybrid Cloud:

Hybrid clouds are still in the development stage; few products and services are available for real-world use

Security controls between private and public clouds; some of these concerns are the same as for public clouds

Challenges of Hybrid Cloud

Challenges from hybrid cloud computing are providing cross-platform, cross-cloud applications, maintaining interfaces and seamless operation across management software. Users want to use data center tools to manage hybrid cloud environments. Ideally, they want to be able to create applications, or move existing applications between clouds in a hybrid cloud environment without having to make any critical changes such as network settings, security policies, business processes or management/monitoring tools. This is a real challenge, and hybrid clouds tend to become more and more complex due to issues such as interoperability, mobility, and different APIs, tools, policies, and processes.

In the follow-up to Hybrid Cloud Systems, we will cover the most prominent hybrid clouds on the market today and identify a best use case for hybrid cloud computing offerings.

Author Bio:

Bill Claybrook is a marketing research analyst with over 30 years of experience in the computer industry and 10 years of experience with Linux and open source. From 1999 to 2004, Bill was Director of Linux and Open Source Research at the Aderdeen Group in Boston. He resigned in June 2009 after a 4.5 year stint in competitive analysis/Linux product marketing at Dell. Currently, he is President of New River Market Research in Concord, MA. He holds a Ph.D. in Computer Science.