What is Virtualization? VM and Virtualization Technology Guideline

• Virtualization Definition

  Virtualization Definition

  What is virtualization? Virtualization is a technology that helps simulate multiple isolated virtual resources or environments using a hypervisor on a physical system or resources.

  You can virtualize various types of hardware resources such as storage, compute, networking, and applications, among others.
• What is server virtualization?

  What is server virtualization?

  Server virtualization is a process of creating multiple virtual machines (VMs) isolated from each other.

  Server virtualization relies on a  virtualization software, a hypervisor that helps you abstract resources from a physical machine and facilitate creating virtual machines. The hypervisor allocates some resources from the physical machine to VMs and enables these VMs to use resources as needed.

  Each VM runs similar to a physical machine and can run a different operating system or application than its neighboring VMs on the same physical machine.

  In server virtualization, three specific terms are used:

  1. Host: The physical machine on which VMs run
  2. Guest: A VM running on a host (physical machine)
  3. Guest Operating System or Guest OS: The VM’s operating system
• What are the different types of hypervisors?

  What are the different types of hypervisors?

  Hypervisors can be classified into two types:

  1. Type 1: Frequently known as a bare-metal or native hypervisor, such hypervisors run directly on a physical machine without requiring an operating system.
     Type 1 hypervisors are relatively simple and provide basic functionality to help create and manage VMs such as VMware ESXi and Microsoft Hyper-V. These are mainly used in data center infrastructure
  2. Type 2: This hypervisor type is also known as a hosted hypervisor. Unlike type 1 hypervisors, type 2 hypervisors run inside an operating system and cannot run directly on a physical machine. This type of hypervisor runs akin to the other applications in an operating system.
     It’s easy to create and manage VMs using the type 2 hypervisors such as Oracle VM VirtualBox and VMware Workstation. These are mainly used in endpoint devices and workstations.
• How to manage virtual machines

  How to manage virtual machines

  In smaller production and test environments, virtualization tools such as hypervisors can help you to create, manage, and terminate virtual machines.

  In enterprise-scale environments, however, you need more comprehensive virtualization tools to manage performance, safeguard VMs, apply configuration changes, and dynamically adjust capacity.

  Virtual machine sprawl occurs when administrators are overwhelmed with the number of VMs due to rapidly growing VM deployments. Using inefficient methodologies and tools to manage VM life cycles eliminates the benefits achieved through virtualization such as efficient resource utilization and cost optimization.

  While virtualization vendors are increasingly adding management features to their core virtualization software, third-party IT vendors offer virtualization tools and management solutions that integrate with core virtualization software’s APIs or leverage SDKs to help you manage VM life cycles.

  Using virtualization management solutions, you can constantly monitor VM environments, take backups, apply security policies, report resource utilization, and automate configuration tasks. Similarly, you can improve overall infrastructure utilization and terminate unused VMs.
• Benefits of virtualization

  Benefits of virtualization

  Virtualization offers numerous benefits mainly by improving organizational hardware utilization and management. Some of these benefits include:

  • Cost-savings: Traditionally, organizations deploy one production application in one operating system environment to ensure reliability. Without virtualization, this approach limits one application deployment per physical machine. 
    However, not all applications fully use the resources available on the physical machine, leading to inflated costs.
    Virtualization alleviates this problem by allowing you to use resources more efficiently through virtual machines, improving utilization efficiency and cutting IT infrastructure costs.
  • Easier Deployments: In the traditional approach, deploying a new application or creating a test environment requires procuring a new physical machine, setting it up, and testing the setup manually. This is time-consuming and becomes chaotic when deploying at scale.
    With virtualization, it’s easier to create new VMs on an existing physical machine. You can also use a snapshot of a similar VM to create a new VM to bring down the time required to deploy an application. This also helps test updates in a beta environment and directly deploy successfully tested VMs without unnecessary back and forth. In case a deployment fails, you can quickly roll back the VM to an earlier state to recover quickly.
  • Operational Agility: When you deploy an application on a physical machine, it becomes especially challenging to deal with machine failures. Even redeploying the application from one machine to another consumes a lot of time. As a result, this can lead to lost revenue as the timely availability of business applications is critical. 
    A significant benefit of VMs is you can shift them from one host to another host almost instantaneously. Moreover, you can take VM snapshots at regular intervals and maintain the most-recent backups. This helps immensely when a host fails fatally or if you need to retire a host nearing its end of life.
• Limitations of virtualization

  Limitations of virtualization

  While virtualization helps flexibly manage resources and improve IT operations significantly, it has some disadvantages:

  • Each virtual machine needs to run its own operating system. This approach consumes additional, redundant resources on a host. A more efficient approach to resource utilization would be containerization.
  • Some applications may not run in a virtualized environment and require deployment on a physical machine.
  • If a hypervisor is compromised, an attacker could gain unauthorized access to all the VMs the hypervisor manages. This presents a significant risk if hypervisors aren’t patched or maintained properly.
  • Initial investments in virtualization technology, monitoring and management tools, and personnel can be significant.