Container: operating system virtualization	Virtual machine: hypervisor-based virtualization
Common features	- Migration between hardware nodes - Root access - Web-based remote control (restart, shutdown) - Backup
Operating system	If you don't need many different operating systems running simultaneously, container-based virtualization is a good alternative and offers virtualization performance benefits.	It is flexible and allows you to install nearly any operating system
Principle	One kernel installed and runs on the hardware node, with several different virtual machines installed on top of it. A virtual machine is not a complete operating system instance, but rather a partial instance of the operating system.	A full operating system is running in a virtual machine.
Advantages	More efficient, high concentration of containers per hardware node (order of magnitude: hundreds of containers per hardware node), low overhead per container. It is therefore more economical and is charged less than an hypervisor-based virtualization. QOS is a best try. The kernel is upgraded by the provider	Free choice and full control on the operating system and its parameters. Full control on version and upgrade of the OS. Fully dedicated resources: CPU, RAM and DISK are dedicated to the virtual machine.QOS (quality of service) is therefore a comitment. The virtual machine presents itself exaclty as an hardware node. Mix of operating system is possible on the same hardware node, convenient to consolidate physical servers on a single hardware node.
Remote access	Depending on OS: shell access or remote desktop connection. Available once OS has booted.	Our virtualization platform provides remote console and keyboard functionality. Available before OS boot (from BIOS bootstrap) Can be used to install OS, exactly as if you were locally connected to the console.
Disadvantages	No control on the kernel: only the provider controls the version and upgrades of the kernel. Only one kernel can run on the hardware node, no mix of OS possible. The provider generally supports a limited number of OS. ServerNest supports Linux Centos 5.x and Microsoft Windows(R) 2008 SP2 64bits	More costy and higher overhead per virtual machine. Customer has full responsibility on maintenance. Less virtual machines can run on  an hardware node (order of magnitude: a few to a dozen per hardware node)
Licence	Operating system licence included in the container price.	OS licence fees not included in the virtual machine price. Licence can be bought over the provider or bring your own licence.
Set-up	Quick, usually ready in a few seconds. Fully automatized by provider.	Longer set-up phase, from a few minutes to hours depending on the operating system. Requires installation of the operating system (e.g: installation from DVD ISO image)
Virtualization platform	Virtuozzo(R) from Parallels(R)	Parallels Bare Metal Server (R)