CISSP 9.16 - Virtualized Systems (Part 1 of 2)

This episode of the ISC2 Certified Information Systems Security Professional (CISSP) exam prep series builds up virtualized systems from the ground within Domain 3. It covers what virtualization is, the hypervisor that runs the guests, how cloud grows from this layer, and the security advantages that let you defend everything built on top of it.

Frequently Asked Questions

What is virtualization, and why do organizations adopt it?

Virtualization lets you run one or more operating systems inside the memory of a single physical host, and even run software that would not otherwise fit the host. Almost any operating system can run on almost any hardware, and many can run side by side at once. The big driver is cost: one organization might collapse a hundred physical servers down to ten, each hosting ten virtual ones, which slashes power, cooling, and operating costs like many tenants sharing one well-run building.

What is the hypervisor, and what are the two types?

The hypervisor, also called the virtual machine monitor, is the engine that creates, runs, and manages the virtual machines, where the physical machine is the host and the systems inside are the guests. A type one hypervisor is bare-metal, installing straight onto the hardware with no host operating system, which maximizes resources and is common for server virtualization. A type two hypervisor is hosted, running as an application on a normal operating system, and suits desktops where guests act as safe sandboxes.

How does cloud grow out of virtualization?

Cloud computing is the natural next step from virtualization, the Internet, and distributed architecture, driven by the need to reach data and resources from anywhere. But moving there raises real questions you must weigh, including privacy, regulatory compliance, open versus closed source choices, adoption of open standards, and whether the data is truly secured or even securable. Cloud gives you reach, but it hands you a fresh set of trust decisions.

What is the difference between elasticity and scalability?

Elasticity is expanding or contracting resources to meet the demand of the moment, so when a heavy job launches inside a virtual machine it can grab spare host capacity, then release it the instant the work finishes. Scalability is the ability to take on more total work over time. Elasticity is short-term and resource-focused, while scalability is long-term and growth-focused. A scalable system must also be elastic, but an elastic one need not be scalable.

What security advantages does virtualization bring?

Backing up a whole virtual system is often faster than backing up its physical twin, and snapshots, also called checkpoints, let you restore a virtual machine in minutes when something goes wrong. Better still, malware that infects a guest rarely reaches the host, thanks to the hypervisor’s isolation between guests and between guest and host. That isolation makes virtualization a safe place to test and experiment, acting like a blast wall between the tenants that keeps trouble from spreading.

Reference: This article is based on concepts discussed in CISSP 9.16 - Virtualized Systems (Part 1 of 2).