Phoronix reports Overlayfs has finally been merged into the Linux kernel. This has been in the works for sometime. LXC supports Overlayfs based containers lxc-clone and lxc-snapshot tools can work with Overlayfs. See our LXC advanced guide for a short intro.

Overlayfs has been merged in kernel 3.18-rc2 so it will be sometime before it flows downstream but this is exciting news. For those who are out of the loop union file systems like Overlayfs allow multiple file systems to be combined and presented to the user as a single tree.

With LXCs existing support for Overlayfs, and support in the vanilla kernel opens new possibilities for building containers using layers.  We will probably do a guide on this. In the interim here are some interesting articles on Overlayfs.

Overlayfs introduction

A post by Serge Hallyn on LXC snapshot with Overlayfs

LWN discussion on Overlayfs

And here is an interesting case of using Overlayfs with LXC containers. This is a QT4 app called virtenv.

You can run GUI apps in LXC containers. For those who missed it there is a guide on how to run Chrome browser and Steam in LXC containers by LXC developer Stephane Graber in his 10 post introduction to LXC 1.0