Features
- Full ssh and root access
- Guaranteed Resources
- 4 processor Xen instances
- Dedicated IP address
- Unlimited traffic
- Datacenters in US and Europe
- Windows, Linux, BSD virtualization
What is Xen Hypervisor?
Xen is an open-source VMM, or hypervisor, for both 32- and 64-bit processor archi- tectures. It runs as software directly on top of the bare-metal, physical hardware and enables you to run several virtual guest operating systems on the same host computer at the same time.The virtual machines are executed securely and efficiently with near-native performance.
A computer running the Xen hypervisor contains three components:
- Xen Hypervisor
- Domain 0, the Privileged Domain (Dom0) – Privileged guest running on the hypervisor with direct hardware access and guest management responsibilities
- Multiple DomainU, Unprivileged Domain Guests (DomU) – Unprivileged guests running on the hypervisor; they have no direct access to hardware (e.g. memory, disk, etc.)
The Xen hypervisor runs directly on the hardware and becomes the interface for all hardware requests such as CPU, I/O, and disk for the guest operating systems. By separating the guests from the hardware, the Xen hypervisor is able to run multiple operating systems securely and independently.
The Domain 0 Guest referred to as Dom0 is launched by the Xen hypervisor during initial system start-up and can run any operating system except Windows. The Dom0 has unique privileges to access the Xen hypervisor that is not allocated to any other Domain Guests. These privileges allow it to manage all aspects of Domain Guests such as starting, stopping, I/O requests, etc. A system administrator can log into Dom0 and manage the entire computer system.
The Domain Guests referred to as DomUs are launched and controlled by the Dom0 and independently operate on the system. These guests are either run with a special modified operating system referred to as paravirtualizion or un-modified operating systems leveraging special virtualization hardware (Intel VT and AMD-V) referred to as hardware virtual machine (HVM). Note – Microsoft Windows requires a HVM Guest environment.
- Paravirtualization A term used to describe a virtualization technique that allows the operating system to be aware that it is running on a hypervisor instead of base hardware. The operating system must be modified to accommodate the unique situation of running on a hypervisor instead of basic hardware.
- Hardware Virtual Machine (HVM)
A term used to describe an operating system that is running in a virtualized environment unchanged and unaware that it is not running directly on the hardware. Special hardware is required to allow this, thus the term HVM.
