fuse-overlayfs/README.md
2022-01-13 16:41:19 -05:00

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fuse-overlayfs
===========
An implementation of overlay+shiftfs in FUSE for rootless containers.
Usage:
=======================================================
```
$ fuse-overlayfs -o lowerdir=lowerdir/a:lowerdir/b,upperdir=up,workdir=workdir merged
```
Specify a different UID/GID mapping:
```
$ fuse-overlayfs -o uidmapping=0:10:100:100:10000:2000,gidmapping=0:10:100:100:10000:2000,lowerdir=lowerdir/a:lowerdir/b,upperdir=up,workdir=workdir merged
```
Requirements:
=======================================================
If you are not using the static build as explained in the next chapter, your system needs `libfuse` > v3.2.1.
* On Fedora: `dnf install fuse3-devel`
* On Ubuntu > v19.04: `apt install libfuse3-dev`
Also, please note that, when using `fuse-overlayfs` **from a user namespace**
(for example, when using rootless `podman`) a Linux Kernel > v4.18.0 is required.
Static Build:
=======================================================
This project provides a convenient way to automatically perform a static build using a container.
The result is a self-contained binary without dependencies, that can be copied across hosts.
1. Install `buildah` as explained [here](https://github.com/containers/buildah/blob/master/install.md);
2. Both the build and deploy host require the special device `/dev/fuse`; there are a few ways to obtain it:
* install `fuse2` or `fuse3` using the package manager of your choice (dnf, apt, pacman, etc):
the install script will usually create the device automatically; or
* manually create the device with the command `mknod /dev/fuse -m 0666 c 10 229`
(see [this code](https://github.com/libfuse/libfuse/blob/f0e08cc700d629da2d46def8b620b0ed858cc0d9/util/install_helper.sh#L35))
3. Clone this repository, and switch to the top-level folder containing the file "`Containerfile.static.ubuntu`";
4. Launch the build with the command (note the single dot `.` at the end):
```
buildah bud -v $PWD:/build/fuse-overlayfs -t fuse-overlayfs -f ./Containerfile.static.ubuntu .
```
5. Copy the resulting binary to your host:
```
sudo cp fuse-overlayfs /usr/bin/
```