Monday, July 25, 2011

Are Cloud Service Models Created Equal - Which One is Right for You?

Trouble Raises Concerns
Organizations are utilizing the cloud in growing numbers, but given the news a few months back about cloud outages, first with Amazon AWS, then Google Blogger and GMail and finally Microsoft BPOS, some organizations are rethinking their strategy and trying to decide how to choose a cloud service model that works best for them. See this article in the NYT for example - Amazon’s Trouble Raises Cloud Computing Doubts.

Even with the outages there is no doubt that the Cloud works for many use cases, however not all cloud is the same. There are different considerations for different applications and choosing the right cloud model is critical to the business. If you are thinking about which cloud model is right for you there are a few things to consider. The primary consideration is whether to go with public or private cloud.

When to use the Public Cloud
With public cloud compute resources are shared and they are accessed over the internet at best effort. When choosing to get services from the public cloud you would consider if regulations concerning data protection will allow it, and if it fits with your corporate goals for availability and recovery. This last concern might be the key deciding factor in cloud service adoption.

Any business that is looking to outsource their IT infrastructure to the cloud must consider the whole of their business before taking the plunge. There is a benefit in having access to resources that are elastic and available on demand. The public cloud can work well for batch work, seasonal, periodic, one-time and some public facing uses cases.

Kevin McEntee, Vice President of Systems Engineering at Netflix explained how they use the public cloud for consumer facing transactions, see Cloud Connect Keynote: Complexity and Freedom. However Netflix still maintain their back office systems in house.

Many organizations that chose the route of acquiring quick and cheap IT services via public cloud have learned a lesson about the need to have priority in the recovery process and control over the network. A prominent cloud outage hinged on the two issues of network availability and access to storage. The details of that outage are explained here: Summary of the Amazon EC2 and Amazon RDS Service Disruption in the US East Region.

While it is possible to configure your public cloud service to deal with outages it isn’t as easy as it sounds. The issues are covered in detail by Cory Hicks, Sr. Manager, Software Engineering at Netflix, in his blog: Lessons Netflix Learned from the AWS Outage.

Private Cloud and Hybrid Cloud
While there are benefits of putting batch workloads and some customer facing services in the public could you might think twice about putting your core business applications there. For core business applications where uptime is critical an alternative is to consider a private cloud model, which allows you to maintain control over the infrastructure and set the terms of service, levels of security, stability and performance of your cloud service platform.

This is not to say that a private cloud has to be entirely owned-and-operated by you. There are cloud service providers who will offer you a managed private cloud, which can provide the cost flexibility of a public cloud service with benefits of a private cloud. This hybrid model where the infrastructure is hosted and managed for the enterprise will likely be the norm in the future.

Priority access to infrastructure and performance of the network are key factors in the reliability of cloud services. Private cloud utilizes infrastructure that is reserved for the customer including compute and storage that is accessed over a private network. Using a private infrastructure platform ensures that you will have resources that are sized for your business critical applications. This can be backed by a contractual arrangement for service levels with your provider, so if something does go wrong you can prioritize the recovery process and ensure and orderly recovery.

There is a considerable benefit in accessing your cloud service over a private network where there is more control over routing and performance levels and where you can obtain service level agreements from a service provider that has an application performance management infrastructure in place and also has a stake in the game. At the recent Uptime Institute Symposium speakers suggested that for business critical applications for the global enterprise the private cloud or hybrid cloud might be the best choice as control is more important than cost.

Choosing the Right Platform
Perhaps the biggest question when considering cloud services should be: "What platform was used to build this cloud?" If you're building your own private cloud, then you have control over the platform and can choose what is right for your organization. If you go the hybrid route you should ask your provider what platform they are using and go with a provider that is deploying a platform that can ensure the performance and scale that you need. Platform choice is an issue that industry analyst Lydia Leong of Gartner covers in her blog: Why transparency matters in the cloud.

There are tremendous benefits to using at platform that is designed for your purposes and is property sized for your requirements, not the least of these benefits is the reliability and predictability that comes with a well-understood infrastructure and the availability of systems level support vs. product level support.

To address the requirements for scale and availability many organizations are deploying private cloud using converged infrastructure platforms and they are adopting a hybrid cloud model based on hosting these platforms with their cloud service provider. One such platform is a Vblock Infrastructure Platform which is a combination of compute, storage and virtualization infrastructure that is pre-engineered, integrated and validated for cloud use cases. The Vblock Platform is delivered by VCE, The Virtual Compute Environment Company, a partnership of VMWare, Cisco and EMC.

To learn More about VCE and Vblock see,

This article first published as Are Cloud Service Models Created Equal - Which One is Right for You? on Technorati.

Backstory: I wrote this blog to promote the value of a hosted private cloud platform while working at VCE. I attended the presentation by Netflix at Cloud Connect and attended the Uptime Institute Symposium where I gathered some of the information used here.

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