DoubleCloud.org

With the growth of virtualization, a new term “virtual appliance” has been coined for a special type of virtual machines that are used like applications. What does it really mean?

First, a virtual appliance is still a virtual machine. When seen in vSphere Client, the virtual appliance does not look much different from other typical virtual machines. Secondly, the functionality of the virtual machine is limited to that of an application. More often than not, the virtual machine is installed with one application. Because of this, the underlying OS is stripped down only to the minimum required to support that application. This type of OS is also called Just Enough OS (JEOS). All the existence of the JEOS is to support the application in the virtual appliance.

Now, is it a VM or an application? It could be either, depending how you look at it. For ESX/vCenter, a virtual appliance is a virtual machine. You can manage it just like any other virtual machine. For application users, it’s an application, a special one that is different from a normal application.  Read more... (500 words, estimated 2:00 mins reading time)