Virtualization Explained

What is virtualization?

Virtualization is a technology that allows us to host multiple virtual machines on a single physical system. It enables us to run multiple operating systems simultaneously on one computer system.

Virtualization is ideal for testing environment. If we need to test a specific software on different operating systems, we can create virtual machines and install the required operating system and test the software. It also provides an isolated environment with no interference from other systems.

Virtualized VS Non-Virtualized Environment

For a better understanding, lets compare a virtualized environment with a non-virtualized environment.

In the scenario below, an organization is using one dedicated server for each of its services, one for database one for e-commerce and other for email client.

To transform this server environment into virtualized environment we need to buy one strong server which must be able to process all queries and requests related to these three services. Then, install a hypervisor on the server and on top of hypervisor, we will create three virtual machines and install required operation systems. Each VM can be assigned to each such service.

Components of Virtualization

To set up a virtual platform, we need at least three components.

Host: it is the physical system where virtualization takes place. It could be a server or your laptop computer. The resources of this system will be allocated to VMs.

Hypervisor: It is a software or firmware that creates, runs, and manages virtual machines. The hypervisor also responsible for interaction between the host and the virtual machine.

Virtual Machine (VM): A VM is a virtual computer system created using hypervisor. We can create multiple VMs on a single system as per our needs as well as under the hardware limitations. A VM is an isolated environment with its own operating system and applications.

Type 1 hypervisor & Type 2 hypervisor

There are two types of hypervisors, type 1 and type 2 hypervisors.

Type 1 hypervisors are also known as bare metal hypervisors because they are installed directly on physical material. VMware ESXi and Microsoft Hyper-V are the examples of type1 hypervisor. We install a hypervisor and then we create and manage the VMs with that hypervisor.

Type 2 hypervisor is little different from type1 hypervisor. On physical hardware, it required a host operating system, which can be windows or MacOS. On the host operating system we install type2 hypervisor of your choice for instance, Oracle VirtualBox or VMware Workstation. Then with this hypervisor, we can create virtual machines as per our requirement.

Benefits of Virtualization

Virtualization has various advantages in comparison with traditional systems. Some of them are discussed here.

Cost Effective

Virtualization is cost effective, various organizations are adopting virtualization to reduce their hardware and operating costs.

Fast Provisioning

Virtualization also provide fast provisioning, so if you need to add a new system you can simply copy the virtual machine from another hypervisor or from your backup.

Minimized Downtime

Virtualization minimizes downtime, in case of a system failure or a disaster, the deployment of virtual machine is easy and quick. We can copy or import a VM, and it will be up and ready to use in a few moments.

Enhanced Security

Virtualization offers better security than traditional networks, due to its secure features like built in virtual firewalls and isolated environment.

Eco-Friendly

Virtualization is considering eco-friendly because virtualized systems consume low energy, produce low noise and low heat as compared to traditional environment.

?Challenges of Virtualization

Virtualization has some challenges too, some of which will be discussed here.

VM Sprawl

VM sprawl occurs when we create a lot of undocumented virtual machines. If multiple users are allowed to create VMS, the system could end up with a lot of unused VMs. These VMs can create security and management issues.

VM Sprawl Avoidance:

To avoid VM Sprawl, there must be some policies and VM control system in place. Large organizations may use a VM life cycle management system. For small-scale use, you can use the appropriate naming convention or any accounting system.

VM Escape

It refers to malware or viruses running on guest operating system, sometimes jump to other virtual machine or infect the host hardware and host operating system.

VM Escape Protection:

To protect the system from VM escape, design a proper and secure network for your VMs and use vendor services to keep your system secure & updated. For small scale usage, keep your host operating system and hypervisor fully patched and updated.

?Resource allocation

The allocation of host system resources to VMs may be challenging if there is no policy in place to create and manage VMs. All VMs on the same host share the resources of physical systems and improper allocation can cause resource exhaustion. Resource allocation must be under the host hardware limitations and should be documented for future allocation.

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Special thanks to David Meece for providing a wonderful platform.

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