Hi all,

While this post isn't exactly Xen, but virtualization related...

I would like to request some leightweight virtualization - containerization (namely OpenVZ) in openSUSE 11.1.

In short: OpenVZ allows very-high density lightweight virtualization. While traditional virtualization (KVM/Xen/VMware) allows for several dozens of VMs per physical machine, OpenVZ allows several hundreds (on powerful hardware even thousands!!!) of VMs running simultaneously. Limitation: Linux-on-Linux only.
Good news: No requirement for hardware VT CPU. (unlike KVM)
Performance: same as Xen for few VMs (i.e. >99%), but as scalability grows big - to several dozens of VMs, OpenVZ outperforms Xen.

Other OSes (Ubuntu/CentOS/RHEL/Solaris) has this type of functionality - either built-in or provided by third party.

Part of it is integrated into mainline kernel (known as cgroups). But since integration is incomplete, host kernel needs to be patched.

Some steps need to be done:
1. Host (openSUSE) kernel needs to be OpenVZ-patched.
2. Guest (openSUSE) OS image needs to be done for OpenVZ.
3. Documentation - official OpenVZ documentation is RedHat centric (very bad for us)

I had difficulty in:
1. Building kernel - I wanted both general-purpose kernel, that also supports containers - and I failed to build one.
When I used their instructions directly, the kernel was built, but it was very limited - i.e. no sound drivers, no other drivers, ... 
I really prefer general-purpose kernels.
OpenVZ kernel should be alternative RPM to the "default" and "bigsmp" kernels.
2. Since OpenVZ uses special images for guest OS templates, I had difficulty understanding that format and preparing those images.
I ended up running CentOS guests on openSUSE host.
3. Documentation (can be done later, I will write some as part of the "Lessons for Lizards" community documentation project for openSUSE)

I wrote an article here:
http://forgeftp.novell.com/lfl/.html/virtualization.html

But I will write much more technical documentation, when I see this project going and the initial difficulties 1. and 2. sorted out.

-Alexey Technologov, 1.Jul.2008.