Chapter 6. Virtualization in the Cloud

Virtualization is a key enabler of cloud but it is not cloud itself. As previously discussed, cloud is defined by the following three attributes: elastic, on demand, metered. Virtualization doesn’t directly enable any one of these three attributes but it does help to enable all three.

Note

Virtualization is a key enabler of cloud but it is not cloud itself.

Virtualization in its various forms enables the following:

Partitioning
Vendors don’t make any money if they can’t pack a lot of their customers on each physical server. Many vendors offer virtualized servers with as little as one physical hardware thread. There are typically two hardware threads per physical CPU core, 12 cores per processor and two processors per physical host. That means a single commodity machine can be divided up into 48 unique servers, each capable of being rented out to an individual or organization. Density is how vendors make their money.
Isolation
Given that partitioning hardware is required to make business models work, isolation is required to keep individual partitions from interfering with each other. You wouldn’t want a CPU-intensive workload like DNA sequencing to interfere with your application server’s ability to respond to HTTP requests. You can provision whole servers from many Infrastructure-as-a-Service vendors, just like you would secure fractional slices of physical servers.
Portability
Virtualization has tooling that makes it easy to take snapshots ...

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