Understanding Virtualization

I want to know about Virtualization in开发者_如何学Go detail. But start from basics, like what is virtualization, with real world examples and scenarios. When ever I search, i got Virtualization technologies, but I want to learn and in fact know what exactly is virtualization, its types and all... Please help me in getting practical details of term "Virtualization"

Virtualization is a big topic, but very roughly speaking there are three main levels of virtualization:

• OS virtualization with a type 1 hypervisor
• Virtual machine that run on an existing hardware/OS, e.g. VMWare
• High-level virtual machines, e.g. JVM

I would recommend this book: Virtual Machines, by J. E. Smith and R. Nair.

It covers pretty much all virtual execution environments: process virtualization, high level virtual machines, system virtual machines, multiprocessor virtualization, etc.

Note that depending on the level which you are interested in, it gets pretty much related to system administration / hardware, so you might also ask the question on serverfault.com.

The question is pretty generic so it can lead to different replies, but I think that you first need to define and understand what is an actual hypervisor and why it is used:

The hypervisor is used to do the abstraction between the physical and the virtual resources. In other words, it is responsible to create a virtualized layer and share the hardware components (CPU, RAM, NIC, storage) to the virtual machines that will be used. Therefore, it is a lot simpler to centralize and manage multiple sources of heterogeneous elements. It is possible to deploy two types of hypervisors:

Type 1 Hypervisor: There is no actual operating system installed on the bare metal server except the software used to deploy the hypervisor. It is especially used in an enterprise context considering that you maximize the resources to share (you do not have the limitation of running an underlying operating system), but it also possible to deploy one in a home lab if you have the required hardware. A classic example is a VMWare ESXi host.

Type 2 Hypervisor: It consists of installing the hypervisor on top of the actual operating system (Windows, Linux, MacOS). It is used especially for testing, deploying simple services and to extend your software capabilities (you can run multiple different operating systems simultaneously). A classic example is Oracle’s Virtual Box.

In your case, I think that the best choice to actually learn about virtualization would be to download a type 2 Hypervisor (Virtual Box or VMWare Workstation Player for instance) in order to deploy a few multiple virtual machines and gain your first hands-on experience.

Specifically, try to explore the different virtual network and storage configurations that are available to differentiate every component.