A virtual machine is a tightly isolated software container that can run its own operating systems and applications as if it were a physical computer. A virtual machine behaves exactly like a physical computer and contains it own virtual CPU, RAM hard disk and network interface card.
Virtual machines can share the physical resources of a single computer, yet remain completely isolated from each other as if they were separate physical machines. If one of the virtual machines crashes, the other virtual machines remain available.
A virtual machine is essentially a software container that bundles or “encapsulates” a complete set of virtual hardware resources, as well as an operating system and all its applications, inside a software package. Encapsulation makes virtual machines incredibly portable and easy to manage. You can move and copy a virtual machine from one location to another just like any other software file.
Rather than purchasing servers, software, data center space or network equipment, you can instead buy those resources as a fully outsourced service. The service is typically billed on a utility computing basis that reflects the level of activity or usage. There is no minimum commitments, allowing you to pay for what you need, when you need it, scaling up or down on demand.
Companies offering virtual machines will provide a secure online account for you on their portal. Using your account, you may manage your virtual machines and monitor costs.