Creating a local workspace for development/testing

Question

I want to be able to mount, say /home/$USER/workspace to /usr/local/workspace. Right now I'm using the python package pyfilesystem which uses fuse to do that. My problem is, that inside that mount I am not able to create symlinks. I don't even need symlinks going outside the mount, but even a symlink that normally is created for a shared library during compilation, will not be created inside the mount.

So I'm either looking for a totally different approach, or a tool (preferably written in Python) that does exactly what pyfilesystem is doing and supports the creation of symlinks.

Further constraints:

• Using a simple symlink instead of a mount does not work for me as the mounted directory will actually be inside a chroot.
• Mounting must not require root privileges.
• Changing fstab is not an option.
• Thus using mount bind is not an option.

Answer 1

Sorry, but such system-wide changes do require some form of root involvement, if just for sanity's sake. Perhaps the nearest to what you want is to create a virtual machine and play in it, or something like Fedora's mock, the mechanism used to create a chroot populated with the required tools to build a package. Probably other distributions have something similar. The whole namespace development in Linux promises help here, there is a series in LWN running now (part 1, part 2, part3, part 4; part 5 is still subscriber-only). But namespace setup will still be a root responsibility.

Answer 2

You can setup a full build/testing environment as a normal user by combining tools like fakechroot, fakeroot and cowdancer.

Answer 3

After searching some more I stumbled upon proot which combines chroot with the ability to mount any directory into the new root. It supports any file operation inside its chroot, yes even symlinks, that will happily work even after proot unmounted the directory. It doesn't need root privileges and made my complicated setup of schroot + pyfilesystem unnecessary.