interlayfs

interlayfs is a tool for composing a Linux filesystem tree from several other trees. It is a variation on union filesystems like aufs and overlay. The key difference is that interlayfs does not provide filesystem layers shadowing the lower layers. Instead, it combines several filesystem trees in a way that the resulting virtual fs tree routes all I/O to the original trees according to the configuration. interlayfs is a mount-like tool for managing complex Linux bind-mount setup in a user-friendly way. interlayfs is actually not a filesystem.

Usage

 interlayfs [-ri] [-o options] --treetab file --pathtab file dir
 interlayfs -u dir

TBD.

Typical Use Case

Mass virtual hosting of interpreted applications. As an example consider a project with

• Vendor scripts
• Customization scripts
• Application data relevant to a single node in a cluster environment - usually temporary or cache files
• Application data shared across nodes - usually persistent user data

TBD.

Contributing

TBD.

Bugs and TODO

• Make up a recursive acronym "interlayfs ... not ... filesystem" :-)
• Implement usage without a root tree?
• Better atomic mounting and umounting using mount --move
• Make environment variable substitutions work more contextually rather than like just "macro preprocessing"
• Add more unit tests
• Add more docs and a man page