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OS Virtualization Interview
VirtualizationBuff writes "KernelTrap has a fascinating interview with Andrey Savochkin, the lead developer of the OpenVZ server virtualization project. In the interview Savochkin goes into great detail about how virtualization works, and why OpenVZ outshines the competition, comparing it to VServer, Xen and User Mode Linux. Regarding virtualization, Savochkin describes it as the next big step, 'comparable with the step between single-user and multi-user systems.' Savochkin is now focused on getting OpenVZ merged into the mainline Linux kernel."
well isn't Linux used mostly for server operations? Virtualization also adds a layer of safety and security between child OSes and their processor.
Uhh... these products aren't aimed at your desktop box. They're for use in server farms, where virtualization provides an additional measure of security, along with providing the server operator more flexibility in how their hardware is utilized.
Nah nah nah. It's going to be great. Picture this. You manage a university computer lab. The computers all have identical software, and all of the students files are stored on a network share. When computers are not in use, you'd like to dedicate the cycles to a long-standing distributed computation for experiments carried out by one of the departments.
The student logs in and a disk image runs their OS of choice, they don't have to reboot or know much, they just click an icon saying which OS, which instantly is presented to them. A batch process manager removes the load from the distributed experiment from their machine.
Or, perhaps something that's already fielded. You're a graduate student, and want to emulate 1000 compute nodes for a distributed computing experiment, you log into emulab, and tell the 50 that you've signed up for to boot 20 OS's a piece, and emulate a 1000 node network.
Or, perhaps you're studying viruses (this has also been done), and want to build an Internet scale honeynet.
Or, perhaps you're running a large server farm. You want an easy way to load balance a multitude of services, so you can run something that looks like 100 servers on perhaps 50. By dynamically balancing across nodes, services can automatically adjust themselves, independently of mechanisms built into their software (to some degree). When you want to add new hardware to the network, you just plug in the machine, and tasks start being farmed to it. When you want to retire some, you just tell the manager to stop moving tasks onto that machine, and wait for the tasks on that machine to move off.
Briefly put, VMMs rock. You have to think outside of "geeks playing with VMWare" to really see the interesting applications though.
Unlike Xen or VMware this OpenVZ doesn't run a separate kernel for each virtual machine. This seems like a security risk to me. A kernel bug will affect all the running virtual machines. In other words, you only need to break one kernel and you have them all.
Plus you can't run different operating systems on each virtual machine.
It does have some positive benefits, it all really depends on what you are doing. I like the security of Xen and VMware better though.
The ratio of people to cake is too big