March 17th, 2006
Red Hat went out public to say loudly about Xen and their plans about that. There is a nice virtualization introduction demo (you need Flash to see it) on their openvirtualization.com site. I have just noticed that if you change the word "Xen" to "OpenVZ", and remove anything concerning "hypervisor", it would be quite an accurate description of what OpenVZ is and what it can do for you. So I welcome everybody to see that demo.
Still, Xen is a bit different. Say, you can not load kernel modules from inside an OpenVZ VPS, or use different kernels for diffrerent VPSs on the same box — but this is possible with Xen.
That leads to the question: what if you need some special kernel module in OpenVZ? The answer is: if it is a device driver and you want to use that device from within one VPS, it is possible (look for '--devnodes' and '--netdev_add' in vzctl man page). If you want to use some special stuff like, say, iptables module, from within a VPS — such module needs to be "virtualized" first (many iptables modules are already virtualized, so you can actually use them from a VPS).
By the way, speaking of that, recently Jason Stubbs, a Gentoo developer, send us a patch to virtualize ipt_REDIRECT kernel module. His work will appear soon in the kernel and vzctl we will release next week. Nice job, Jason!
Still, Xen is a bit different. Say, you can not load kernel modules from inside an OpenVZ VPS, or use different kernels for diffrerent VPSs on the same box — but this is possible with Xen.
That leads to the question: what if you need some special kernel module in OpenVZ? The answer is: if it is a device driver and you want to use that device from within one VPS, it is possible (look for '--devnodes' and '--netdev_add' in vzctl man page). If you want to use some special stuff like, say, iptables module, from within a VPS — such module needs to be "virtualized" first (many iptables modules are already virtualized, so you can actually use them from a VPS).
By the way, speaking of that, recently Jason Stubbs, a Gentoo developer, send us a patch to virtualize ipt_REDIRECT kernel module. His work will appear soon in the kernel and vzctl we will release next week. Nice job, Jason!

Comments
Do you still stand by your opinions above now in 2016?…