User-space NFS Server (UNFS3)
This image implements the User-space NFSv3 Server (http://unfs3.sourceforge.net/)
The official description: "UNFS3 is a user-space implementation of the NFSv3 server specification. It provides a daemon for the MOUNT and NFS protocols, which are used by NFS clients for accessing files on the server."
A number of Docker host platforms don't offer a kernel-space NFS daemon such as Tinycore or CoreOS, limiting their ability to successfully run other Docker NFS server images such as https://github.com/cpuguy83/docker-nfs-server or https://github.com/pandrew/docker-nfs-server.
Although these platforms can be custom-built with NFS daemon support, implementing a user-space NFS daemon circumvents the need to go through the non-trivial process of configuring and building such an OS image.
The current UNFS3 implementation is fairly simple and uses a statically linked /etc/exports file. To add your own exports entries you must use a volume mount to link to an exports file on the host with -v /path/on/host/exports:/etc/exports - this way a new export entry can easily be made on the host. This image will be updated at a later time to allow shares to be defined at docker runtime, as is common with aforementioned NFS server images. More advanced configuration through etcd is also in the works.
Prepare an exports file on the host:
$ echo "/to/share (ro|rw)" >> /host/path/exports
Run Docker and mount any number of host-based volumes or volumes from other containers at the guest path(s) specified in the exports file:
$ docker run --rm -d -p --privileged -p 111:111/udp -p 111:111/tcp -p 2049:2049/udp -p 2049:2049/tcp (-v /host/path:/to/share | --volumes-from <container>) -v /host/path/exports:/etc/exports --name unfs3 macadmins/unfs3
Adding an exports entry
$ echo "/some/other/path (ro|rw)" >> /host/path/exports
$ docker stop unfs3 && docker start unfs3
Or if using CoreOS:
$ systemctl restart unfs3