Hybrid cloud

 General description

  • Composition of at least one private cloud and at least one public cloud.
  • Safe connections are needed between private and public clouds.
Fig. 5.5/1
Fig. 5.5/1 - Hybrid cloud
A few years ago, the IT world was focused on public cloud computing. In 2010, after IT directors expressed concerns over public cloud security issues, the focus shifted to private clouds. And now, because everyone wants operational flexibility, hybrid clouds are at the top of the wish list.
Several recent cloud surveys confirm these high levels of interest in hybrid cloud. A Unisys survey in January 2011 indicated that 21% of IT organizations are focusing on hybrid clouds, and a 2010 Sand Hill Group survey of over 500 IT managers indicates that hybrid cloud use will triple over the next three years.
Hybrid cloud
A hybrid cloud is a composition of at least one private cloud and at least one public cloud. The private cloud can be an on-premises private cloud or a virtual private cloud located outside the enterprise data center. The illustration shows one of the simplest macro views of a hybrid cloud: a single private cloud connected to a single public cloud.
A hybrid cloud could also theoretically consist of multiple private and/or public clouds. The enterprise data center denoted in the illustration might have active servers (virtualized or physical) that are not included in the private cloud.

 Primary goals of a hybrid cloud

Leveraging a hybrid model accomplishes several goals.
Using a hybrid model is a valuable approach to architecture, considering you can mix and match the resources between local infrastructure, which is typically a sunk cost but difficult to scale, with infrastructure that is scalable and provisioned on demand. You place the applications and data on the best platforms, then span the processing between them.
The use of hybrid computing acknowledges and validates the fact that not all IT resources should exist in public clouds today—and some might never exist in public clouds. Considering compliance issues, performance requirements, and security restrictions, the need for local is a fact of life. This experience with the hybrid model helps us all get better at understanding what compute cycles and data have to be kept local and what can be process remotely.
It provides a clear use case for public cloud computing. Specific aspects of existing IT infrastructure (say, storage and compute) occur in public cloud environments, and the remainder of the IT infrastructure stays on premise. Take the case of business intelligence in the cloud—although some people promote the migration of gigabytes of operational data to the cloud, many others find the hybrid approach of keeping the data local and the analytical processing in the cloud to be much more practical.

 Hybrid cloud advantages and disadvantages

Hybrid cloud advantages
The main objective of the hybrid cloud is to take advantage of public and private cloud benefits. However, some of the risks and disadvantages of public and private clouds are not always solved in hybrid clouds.
The challenge of hybrid computing is to provide seamless operation across platforms, cloud application programming interfaces (APIs), and hypervisors. Users prefer to use their data center tools to manage hybrid cloud environments. Ideally, they want to be able to create applications, or move existing applications between the clouds in a hybrid cloud environment, without having to change anything serious like networking, security policies, operational processes or management/monitoring tools. This could be a problem due to issues around interoperability, mobility, differing APIs, and tools, as well as policies and procedures.
Clouds generally increase complexity.
With the use of a hybrid cloud computing model, a company can capitalize on the advantages of keeping data secure while outsourcing infrastructure and other computing services to the cloud. This enables an effective ROI, cost, and ease-of-use benefits, while reaching a broader market. A hybrid cloud environment seamlessly integrates such external applications available on the private and public clouds, with your own in-built processes.
Hybrid cloud disadvantages
Hybrid clouds are based on public and private clouds, it is this dichotomy that poses security issues for hybrid cloud computing (that is, mixed public and private) when compared to dealing with its individual components.