corezfs | ZFS on Linux on CoreOS

corezfs is a Shell library. corezfs has no bugs, it has no vulnerabilities, it has a Permissive License and it has low support. You can download it from GitHub.

CoreOS is a light weight linux distribution designed specifically for running containers but does not currently come with support for ZFS. The idea is the only thing CoreOS does is coordinate containers and all work is performed inside containers. CoreOS is also very focused on reliability, clustering and federating with support for things like kubernetes baked in. ZFS is a very performant filesystem that supports error checking, snapshots, clones, native nfs and cifs support, and incremental backups. The ZFS on Linux project is a port of OpenZFS for Linux. Because the design philosophy of CoreOS is to be a minimal "container orchestration" tool, it is locked down very tightly and most of the file system is read only, which presents a problem for software which requires kernel modules (both because containers need special permissions to communicate with the kernel, and because the CoreOS kernel modules folder is read only). This script downloads a CoreOS development environment and runs it in a container to build zfs and create the archive file. The archive file is a tar file containing an /etc/ directory containing zfs configuration information, and an /opt/corezfs/usr directory which is overlaid over the /usr filesystem and contains the kernel modules and binaries. A systemd unit file called zfs-overlay.service (included in the /etc/ directory of the archive file) mounts the overlay at startup. This script was written on CoreOS stable (1465.7.0), but in theory, will work on any version / channel (ie. stable, beta, alpha). It installs the latest release of ZFS on Linux which is based on OpenZFS and consists of a repository zfs which includes the upstream OpenZFS implementation and a repository spl which is a shim to run OpenZFS on Linux. Note that the script does not effect the filesystem that CoreOS is mounted on, it allows additional block devices to be mounted using the ZFS file system. Hopefully this script will allow more people to experiment with ZFS on CoreOS to gain enough support that the CoreOS developers will bake it into CoreOS (note that this implementation does not gracefully handle updates to the CoreOS OS).