Date: January 19, 2025

Topic: Introduction to Virtualization

Recall

Virtualization gives the illusion of owning a platform and being able to run apps on top of this without actually being given the physical platform which can result in cheaper costs.

Notes

Platform Virtualization

Virtualization is extensibility applied at an entire OS level

A platform is an OS running on top of some hardware. Virtualization allows running of a real platform at a fraction of the cost

Instead of a real platform (Alice Inc), we use a virtual platform which is cheaper (Bala Inc)
Bala Inc is not concerned what goes on inside the black box (virtual platform), just want to make sure apps can run on top of this platform
- As long as it can provide the same abstractions and capabilities for running the applications, Bala Inc is satisfied
Virtualization gives the illusion of having his own platform without actually being given one

Instead of acquiring resources individually, companies can share hardware resources through cloud providers which scale with their usage.

This reduces costs and also allows each individual company to anticipate sudden spikes in resource demands since collectively, the amount of usage is almost consistent.

Utility Computing

Sharing hardware resources across several different user communities allows cost of ownership and maintenance of the shared resources cheaper

Many companies can share the same hardware resources
Resource usage is typically in a burst

Memory Usage Example

Adding dynamic needs of different user communities, we can get a more stable cumulative usage pattern
For any one company, they would need to purchase resources as much as the peak usage (not cost efficient)
Virtual machine has resources that is much more than individual needs of any one company
Cost of the total resources is also shared among them
Furthermore, each company has access to a lot more resources while paying a fraction of the cost
- Can potentially hit up to total available if needed
Maintaining and upgrading the resource is shared across the companies

Native hypervisors run directly on top of the shared hardware and interferes minimally with the guest OS operations. It also offers the best performance for the guest OS

<aside> 📌 SUMMARY: Platform virtualization allows Guest OS to run on top of some shared hardware. In this way, the Guest OS are able to access much larger resources if needed, and the cumulative usage across would be fairly consistent. Two types of hypervisors exist - Bare Metal, which runs directly on top of the shared hardware, and Hosted, where the hypervisor runs on top of a Host OS. Two types of virtualizations also exist - Full-Virtualization, where the Guest OS run with unchanged binaries, and Para-Virtualization, where some part of the Guest OS (<2%) is modified to allow for optimizations

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