Virtualization and Cloud Computing Concepts

Virtualization

Virtualization usually refers to running software on a computer to create a virtual machine (VM), an environment that imitates a physical machine.

• Hardware underutilization: A server (or a desktop PC, for that matter) isn’t being used anywhere near its capability.
• Hardware virtualization: Virtualization enables one machine—called the host—to run multiple operating systems simultaneously.
• Virtual machine: special program, running in protected space that enables all the features of the server to run as though they are each separate computers.
• Hypervisor: The program used to create, run, and maintain the VMs.
• Two type of Hypervisors

Abstraction

Abstraction is therefore both a concept and a noun, defining the process of separating functions into discrete units; those discrete units are abstractions.

Flexibility

Replacing hardware components with software generally adds flexibility in how you use that virtual hardware.

Reroute an Input or Output

• Input: VM has no such physical ports or drives so you can rout input from either the host’s physical slot/drive or from a disk image file saved on the host .
• Output: A virtual printer can save the output as a PDF without wasting ink or paper.

Relocate Components

• The VM is just a file. If it needs a faster processor or more RAM, just move the file to an upgraded machine running a compatible hypervisor.

Divide and Combine Resources

• You can divide your resources and give each VM its own fraction or you can combine resources as a single VM with powerful resorces.

Scaling