In the past year, private clouds have dominated discussion amongst IT managers, mostly due to concerns over the security of public clouds. But public clouds are also very appealing, especially for applications and data where security is not a large risk; they're ideal for bursty applications that need peak computing power and storage for short periods of time.
We expect IT organizations that build private clouds will eventually look to extend their cloud model to hybrid clouds, meaning that those building a private cloud consider the extensions needed to expand to a hybrid cloud.
These are six considerations to keep in mind when planning for hybrid clouds:
- Security: Security in a hybrid cloud has to happen at the site where the transfer begins, as you'll need to encrypt data before sending it. The data comes across encrypted and the public cloud service provider would not be able to decrypt it. You'll also need a secure VPN. The public cloud needs to know who is accessing resources, but it does not need to know what is going on inside the application. The question is: How can data be farmed out to public clouds and then brought back in securely so that it is not exposing the private cloud to any kind of public breach?
- Hypervisor usage: If the hypervisor(s) used in the private cloud differ from what's being used in the public cloud, then you need efficient conversion package(s) that can be used when data and applications are moved between your private and public clouds. If your private cloud is using KVM or VMware ESX and you want to use Amazon (and the Xen hypervisor), then you'll need conversion software.
- Developing a hybrid cloud environment is difficult: There are no out-of-the-box solutions for a private cloud, and certainly none for a hybrid cloud. If you find a vendor that claims that he can build you a hybrid cloud environment, then you will be locked in to their products for a long time. As of right now, you have to patch together software from a number of vendors to build private and hybrid clouds.
- Understand your data: The ability to run applications in a private cloud during peak usage hours and then offload to the public cloud during off-peak hours affords enormous flexibility. This provides maximum use and efficiency of both internal and external resources. You need to know which data needs high security, which data must be compliant with regulatory requirements and which data you can safely farm out to public clouds.
- Communication between private and public clouds: You need a trusted arbitrator between the private cloud and the public cloud that allows you to make decisions on what goes to the public cloud. You'll also need to monitor the public cloud's delivery of resources to make sure that they are sufficient for what you need. You will not generally know whether your applications are running in the data center downstairs or in an Amazon public cloud. The capability to know where your applications and data are physically located is important because you do not want them moving from private to public and back again too frequently.
- Management: Hybrid clouds require greater levels of automation management to achieve higher degrees of availability, performance, and security.
According to Ken Ferderer, CTO at LineSider Technologies, the goal of hybrid clouds is that as you run out of capacity in the private cloud, you can quickly reach out to the public cloud to get the resources that you need to operate your business, providing a balance between private and public clouds. During critical times for the use of mission critical applications, you can bring them inside the private cloud. When they do not have as high demand, or they are not in use, you push them out to the public cloud. The idea is to move virtual resources back and forth without impacting things like security and without disrupting service. Hybrid clouds are considered the nirvana of cloud computing.
About the author:
Bill Claybrook is a marketing research analyst with over 30 years of experience in the computer industry, with the last 10 years in Linux and open source. From 1999 to 2004, Bill was Research Director, Linux and Open Source, at Aberdeen Group in Boston. He resigned his competitive analyst/Linux product marketing position at Novell in June 2009 after spending over four and a half years at the company. He is now President of New River Marketing Research in Concord, Mass. He holds a Ph.D. in Computer Science.
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