What is a Hypervisor?
What is a Hypervisor?

What is a hypervisor?  The hypervisor is the foundation upon which virtualization runs.  It’s a computer system that allows virtual machines to run on physical machines.  It allows for the creation, management and use of guest machines inside the host operating system.  The guest machines share the resources of the host hardware for compute, power, bandwidth and storage.

What Is a Hypervisor Used For?

The hypervisor allows for the installation and management of virtual machines on a physical host machine.  Virtual machines allow for the installation of many different operating systems, all serving different purposes, on the same physical hardware.  For example, a single physical Windows 2012 r2 Server running a Hypervisor could host machine multiple installations of Linux, macOS and Windows operating systems.  Each guest machine can be configured with different system resources to run different processes and applications independent from the host machine.  In short, the hypervisor enables users to easily realize the many benefits of virtualization.

How To Use a Hypervisor

Using a Hypervisor to manage your virtual machines is very simple.  Usually the hypervisor contains a list of virtual machines in the left panel.  On the right panel, there is information about the individual virtual machines.  The following information is usually given for each VM:

  • Capacity
  • Free Space
  • IP Address (and other network information)
  • Status
  • Memory
  • Processor

vmware-hypervisor-gui

 

 

 

 

 

 

Virtual machines can be provisioned by editing their properties.  This will allow you to adjust RAM, CPU, storage allocation and other settings.  It will also allow you to delete, reboot, start and shutdown machines.

Pros of Using a Hypervisor

The biggest single advantage is virtualization.  With virtualization, the cost of hardware and system administration is drastically reduced.  Instead of purchasing many pieces of physical hardware, a single host machine is all that is needed.  Therefore, the maintenance and replacement costs for the physical systems is nearly eliminated.

Hypervisors also allow for the centralized management of virtual machines.  The hypervisor is what provides the graphical user interface (GUI) that makes VM administration easy and intuitive.

Finally, the hypervisor has built-in features for backups, snapshots, resource management and restore functionality.  The ability to quickly and easily restore a VM from backup can be a game-changer when the unthinkable happens.  Because they run on virtualized hardware, VMs are much easier and quicker to restore.  This means less down-time and fewer headaches.

Cons of Using a Hypervisor

This biggest knock against using a hypervisor and virtualization is the single vendor.  One vendor usually provides the entire virtualized solution, including the choice of hypervisor.  Consequently, if there are any issues there is a single point of contact, rather than several related vendors who can all troubleshoot and fix issues.  It is of paramount importance that vendors are vetted thoroughly, both on technical skill and customer service.  Getting stuck with a bad virtualization vendor can sink a project in a hurry.

Another concern when going virtual is the large cost of implementation.  There will likely be hardware, software, consulting and training expenses to account for.  While cost is a concern, ROI is fairly high, and the initial investment will be recouped over time.

Hypervisor Security Concerns

Hypervisors are generally safe a secure.  The largest concerns is that of unlimited access.  If a hypervisor is hacked, or someone gets the administrator password, upon login they have access to all the virtual machines and resources running on that hypervisor.  For many organizations that could be their entire operation.  Web servers, databases, applications, file access and more could all be taken offline or wiped in seconds.  With this in mind, only trusted administrators should be given access to the hypervisor.  Further, strict password polices should be in place and enforced.

Conclusion

Virtualization is nothing new.  That doesn’t mean, however, that it isn’t still valuable for your business.  Virtualization can mean substantial savings and reduction in administrative overhead for many businesses.  When implementing virtualization, your choice of hypervisor will have a large impact on the day-to-day management of your virtual servers.

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