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Creating a hybrid cloud: key considerations

Hybrid cloud is a federation between internal IT and public cloud, wherein some applications are hosted internally while a few others are delivered via a public cloud. This allows organizations to seamlessly scale up

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from the internal to the external infrastructure or down from the external to the internal cloud as per resource requirement.

Here are a few things to consider when creating a hybrid cloud environment:

Identify applications that can be moved to the public cloud

The first step to creating a hybrid cloud is to identify applications that should stay on-premise and those that can be moved to the cloud.

-   Some applications have high availability requirements and response times. Functioning of these applications could be affected due connectivity issues or latency. For example any transaction processing application, if scaled up to the public cloud, or a BI application drawing data from data warehouses spread across multiple clouds will have a lower response time in the hybrid cloud due to latency issues.  Applications such as CRM and e-mail which do not need to provide results in real-time could be moved to the public cloud.

-   Certain applications may process sensitive or confidential information. Security is an important aspect that needs to be considered when moving this data within the hybrid cloud infrastructure. Depending upon what application an organization defines as critical according to its policies, anything ranging from an ERP application to a mailing system can have security concerns when being scaled up or down within the hybrid cloud.

-   A few applications that have static licensing models may not be suitable for running on a cloud infrastructure. An application aimed at running on the cloud should have a licensing mechanism that scales up or down in accordance with the number of instances of that application on the hybrid cloud.

An organization creating a hybrid cloud should set the necessary SLA expectations with the cloud service provider to ensure that requirements related to uptime, performance and security are met.

Interfacing the internal IT infrastructure with the public cloud

To create a hybrid cloud it is necessary that the internal and the external clouds are running on similar platforms. For example integration between an internal cloud running on UNIX and an external one, running on Windows will be difficult.

The application or the platform on which the application runs needs to be aware of federation between the two or more cloud infrastructures in a hybrid cloud environment. This awareness would allow workloads to be throttled from the internal to external cloud and scaled back into the internal cloud depending on the performance requirements.

Most cloud infrastructure platforms for creating a hybrid cloud environment provide this capability. The platform monitors the performance of the internal cloud and opens up a ticket to the external cloud for the application workload to be processed from the public cloud when resource utilization levels reach their thresholds.

These integrations can be created at the application level through coding by taking the Web services, SOAP or SOA based approaches. It is necessary that the APIs of applications on the two IT infrastructures are exposed and available for creating the interconnection and integration between them.

Managing the hybrid cloud infrastructure

The cloud service provider typically provides a cloud management console. The organization would have deployed an infrastructure management platform to monitor and manage Internal IT. While both may offer resource provisioning and resource monitoring capabilities they would not offer performance management capabilities that allow automatic scaling of resources as per consumption.

The two management platforms need to be integrated to provide a single view of the hybrid cloud. However neither provides the functionality to do so and therefore would require add-ons or plug-in components which provide the functionalities to manage the two infrastructures as a whole.

A lot of third party vendors offer components that help create a layer of these functionalities on the existing infrastructure management platforms. These functionalities allow managing the hybrid cloud singularly by providing the automated monitoring and provisioning functionalities.

While vendors such as BMC, CA, HP, IBM and others offer such functionalities to an extent, there are other third party vendors such as RightScale and Mashery that exploit the APIs provided by the public cloud service vendors to offer a management console that allows monitoring and managing both the internal IT and the public cloud.

About the author: Karthik Ramarao is Principal Consultant for Unified Computing, Solutions Development Group, Datacraft Asia. He is currently playing a key role in Datacraft’s collaborative efforts with BSNL, India’s largest telco, to setup a cloud infrastructure.

(As told to Harshal Kallyanpur)

This was first published in February 2011

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