An application and its operating system packaged together for a virtualized environment such as VMware or Xen. A virtual appliance is the software equivalent of a hardware device that performs a fixed set of functions (see hardware appliance). See system image.Faster and SimplerThe regular process of deploying a new application in a virtualized computer is to set up a new virtual machine (VM) partition, install the operating system and then the application. The processes are time consuming and configuration mistakes can be made. In contrast, virtual appliance deployment is faster because the appliance image (application and OS) is copied to the virtual machine pre-installed and pre-configured. The application and OS have already been tested together, and running the software is less error prone. See virtual machine, virtualization, software appliance and NFV.