Previously, I blogged about differences between hosting and cloud on cloudops.com. To continue with the theme of contrasting Infrastructure as a Service (IaaS) cloud to things that are often confused with cloud, in this post I will compare IaaS cloud to virtualization. First off, SaaS can run on cloud, but is not cloud. I am strictly referring to an IaaS cloud.
Cloud is an operational model
I suggest we agree to use the NIST definition for cloud computing. Adopting the technology is not enough. Cloud technology needs to be adopted in a way that allows the users to self-serve. At cloud.ca, we believe cloud has to have APIs for infrastructure services that are developer-friendly. Automation using these APIs is essential for getting value out of cloud operations. Host virtualization is simply a technology.
Cloud does not require host virtualization
Virtualization is a great technology that lets us create many from one. We can create multiple virtual machines running on a single physical machine. It is frequently used by IaaS cloud, but even in our Canadian cloud - cloud.ca, it is not required. It is still cloud if you are respecting the NIST definition and deploying directly on physical hosts, often referred to as bare-metal clouds. Bare-metal zones in clouds do not use host virtualization at all.
Cloud can free you of addiction to expensive crutches
In the world of host virtualization, the virtualization layers are often used an expensive crutch to maintain system stability and availability. Host virtualization vendors encourage enterprises to license lots of features that seem to promise 100% availability of infrastructure services. However, these features restrict users to specific vendors and specific versions of their platform[s], resulting in lock-in with the vendor and the specific platform version. On an IaaS cloud, applications should be deployed and replicated in a way that is infrastructure agnostic. The stability and availability becomes a responsibility of the operator instead of the infrastructure. Cloud operations result in greater agility and leverage over your cloud service providers.