containerfs

An implementation of overlay+shiftfs in FUSE for rootless containers.

Known issues:

A known issue is that containerfs reports a different inode even if the inode on disk is the same, as with hard links.

The current implementation keeps in memory the entire tree of the lower directories. A side effect is that modifications to the lower layers is never propagated to the merged directory. Overlayfs doesn't allow changes to the layers as well, altough since there is not such caching done, changes are usually propagated.

Read-only mode is not supported, so it is always required to specify an upperdir and a workingdir.

Usage:

$ containerfs -o lowerdir=lowerdir/a:lowerdir/b,upperdir=up,workdir=workdir merged

Specify a different UID/GID mapping:

$ containerfs -o uid=0:10:100:100:10000:2000,gid=0:10:100:100:10000:2000,lowerdir=lowerdir/a:lowerdir/b,upperdir=up,workdir=workdir merged