The Virtualization Illusion
Cloud computing is based in one way or an other on the basic idea that
The Virtualization Illusion is maintainted. The basics of the illusion are:
- All end user computing is done on virtual hardware (CPU, RAM and storage at a minimum)
- There is no difference from the end-user's point of view if it is real or virtual hardware
In a typical cloud configuration this means you can run many virtual machines on each real machine. When people talk about how cloud computing (as distinct from cloud hosting) will save IT a sigificant amount, they are refering to the above ability.
Please note when we talk about being inside or outside the illusion, we do not mean just the VM's it runs on but all the components of the illusion including networking, if the networking or other service is virtual. In other words, if you're inside the illusion there should be no way to see out of it, and similarly there should be no way to see into it from the outside. However, the recursion theorem from The Theory of Computation implies that the illusion cannot be maintained completely 100% of the time.
Maintaining and Enhancing the Illussion
The virtualization illusion is maintained by creating virtual versions of the RAM and CPU. Storage and networking are funny in-between things in that they can be "backed" by real hardware but within its current (virtual) execution context be run as if it is virtual. Once the illusion is established it can be enhanced (usually by the means of software running inside the illusion vs. from outside of it). For how PetiteCloud allows you to take the blue pill see the
documentation page.
Once the illusion is established and maintained it can be enhanced with, among other tricks, virtualization the location of the resources. The creation of this secondary illusion and it's management is the domain of higher layer cloud platforms and will not be discussed here.
The Unexpected Effects of Breaking the Illusion
The primary problem that occurs when the red pill is available is security. Namely if someone can break out of the illusion then they would be able to control the illusion and do other very interesting things (like fly). The security implications for the most common types of red pills are show below:
- "The world is not real", the illusion is too thin and/or pushed to it's limits. In the spots where the illusion fails it is often possible to read/write data to the host (the machine the VM is running on)
- "Time slip", time inside the illusion moves at a slower pace then time outside of it, if you can predict when a time slip will freeze the instance up. it is possible to place data on the host that will be executed blindly
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