Virtualization in cloud computing

The key component in cloud computing is virtualization. The roots of virtualization trace back to the mainframe computers of the 1960s and 1970s. At the time, mainframes could run only one application at a time. These very expensive machines were designed so that they could handle the peak demand. However, such peaks only occurred briefly, meaning that 99 percent of the time, these resources were left unused. By logically dividing the mainframe’s resources — creating smaller, virtual mainframes within the mainframe — developers were not only able to run multiple applications at once but also better utilize the machine’s computing power.

While the intervening decades have seen a number of changes in the technology landscape, the underlying concept of virtualization has remained: combining unused physical resources into a number of virtual ones. Today, the term virtualization is almost always used to mean OS virtualization, the ability to run multiple OS on a single physical machine.

In cloud computing, virtualization allows a cloud service provider to deliver on-demand resources to its consumer base. However, virtualization also represents many of the vulnerabilities that are specific to cloud computing. Since several consumers rely on the same physical hardware, one demanding operation can impact the availability of resources for other consumers. Further, a failure of that hardware will impact multiple consumers. Another issue is with all these organizations sharing the same physical resources via their virtual machines, if someone managed to break one virtual machine, he or she may be able to gain access to the other virtual machines.

Components of Virtualization

Virtualization is comprised of three main components:

  1. The host is the machine on which the virtualization software runs. It can be either a physical machine or a virtual one.
  2. The guest is the virtual machine running on a host.
  3. The hypervisor, also known as the virtual machine monitor, is the software layer on host and creates the virtual environment for the guests.

Further, the industry recognizes two broad types of hypervisors. Type 1 hypervisors run directly on host hardware. There is no intervening host OS, and often Type 1 is referred to as a “bare metal” hypervisor. Type 2 hypervisors run on top of a host operating system. From a security standpoint, Type 1 hypervisors generally have fewer vectors for attack since they do not require a host operating system. That said, since they tend to be written for specific hardware, there may be issues with compatibility and porting to different hardware configurations. Type 2 hypervisors tend to have better support for varying hardware but come with the tradeoffs inherent with having to run an underlying OS. Also, there are hypervisors, such as the Linux-based Kernel Virtual Machine (KVM), that seem to fall somewhere between Type 1 and Type 2.

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Review Checkpoint

To test your understanding of the content presented in this assignment, please choose your selected response.

1. True or False?

A hypervisor is a security device that filters network traffic.Choose only one answer below.

a. True

b. False

Correct. This is a false statement. Hypervisors are a core component of virtualization. They are the software/firmware that enables hardware to run multiple virtual machines.

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