Discussion on:

Introducing Linux virtual containers with LXC

Thank you; this is an area of intense interest for us. We have been very happy using VServer rather than OpenVZ and thus are very interested to know how LXC compares with VServer on several fronts.

Resource utilization:
The hashify feature of VServer is a life saver for systems with many similar virtual servers (containers). It takes duplicate files in the file system between containers and replaces them with immutable hard links maintaining only one actual copy. The disk space savings can be enormous. Is there anything like this in LXC?

Capabilities:
The fine grained tuning of capabilities, what can and cannot be done in a container, is a great feature of VServer. Is there this kind of control in LXC?

Memory Consolidation:
We are very interested in how KSM will play with both VServer and LXC. Can it be used to consolidate memory between containers within LXC?

Thanks again. This is very helpful - John

Actually openvz is available directly from my distro vendor - out of the box, as debian and ubuntu both support openvz. Just a simple apt-get, a reboot into the openvz kernel, and we're ready to start creating containers.

Sure, some distros would have OpenVZ support in them by doing the patchwork themself. Not all distributions do. With LXC being part of upstream, all vendors can provide LXC support with minimal effort.

The OpenVZ kernels provided by Ubuntu and Debian have always been based on devel branches of the OpenVZ kernel rather than the stable branches... which are RHEL4 and RHEL5 based. As a result, fixes and features have always lagged behind in the devel branches and Debian especially has often had rather outdated versions of the OpenVZ userspace tools... although I hope they are caught up by now.

The future looks brighter though because the OpenVZ Project head said that they are working on a new stable branch based on 2.6.32 which is the kernel that will be in the next Debian, Ubuntu and RHEL releases. They hope to get it done prior to the release of the next Debian... and most surely before RHEL6 which is due sometime this summer. Whether that will pan out remains to be seen. I certainly hope it does.

I also hope that LXC matures and the userspace tools for it mature so even more people can take advantage of containers with them being supported in the mainline kernel.

The OpenVZ Project's goal has always been to get containers into the mainline so they could stop maintaining such a large, third-party patch that has no way of getting into mainline itself.