Mounting nfs shares inside docker container

Question

Does anyone know how to mount nfs share inside docker container with centos base image? I've tried this command:

mount server:/dir /mount/point 

and got the next error:

mount.nfs: rpc.statd is not running but is required for remote locking.
mount.nfs: Either use '-o nolock' to keep locks local, or start statd.
mount.nfs: an incorrect mount option was specified

when I try to use it with -o nolock option, the error is:

mount.nfs: Operation not permitted 

Answer 1

Starting from docker 17.06, you can mount NFS shares to the container directly when you run it, without the need of extra capabilities

export NFS_VOL_NAME=mynfs export NFS_LOCAL_MNT=/mnt/mynfs export NFS_SERVER=my.nfs.server.com export NFS_SHARE=/my/server/path export NFS_OPTS=vers=4,soft  docker run --mount \   "src=$NFS_VOL_NAME,dst=$NFS_LOCAL_MNT,volume-opt=device=:$NFS_SHARE,\"volume-opt=o=addr=$NFS_SERVER,$NFS_OPTS\",type=volume,volume-driver=local,volume-opt=type=nfs" \   busybox ls $NFS_LOCAL_MNT 

Alternatively, you can create the volume before the container:

docker volume create \   --driver local \   --opt type=nfs \   --opt o=addr=$NFS_SERVER,$NFS_OPTS \   --opt device=:$NFS_SHARE \   $NFS_VOL_NAME  docker run --rm -v $NFS_VOL_NAME:$NFS_LOCAL_MNT busybox ls $NFS_LOCAL_MNT 

• Got the hint from https://github.com/moby/moby/issues/28809
• official docs from docker: https://docs.docker.com/storage/volumes/#create-a-service-which-creates-an-nfs-volume

Answer 2

For using mount, you'll need the CAP_SYS_ADMIN capability, which is dropped by Docker when creating the container.

There are several solutions for this:

1. Start the container with the --cap-add sys_admin flag. This causes Docker to retain the CAP_SYS_ADMIN capability, which should allow you to mount a NFS share from within the container. This might be a security issue; do not do this in untrusted containers. [A previous version of this answer suggested using the --privileged=true to retain all capabilities, thanks to @earcam for the suggestion to use --cap-add instead].

2. Mount the NFS share on the host and pass it into the container as a host volume:

   you@host > mount server:/dir /path/to/mount/point you@host > docker run -v /path/to/mount/point:/path/to/mount/point 

3. Use a Docker volume plugin (like the Netshare plugin) to directly mount the NFS share as a container volume:

   you@host > docker run \   --volume-driver=nfs \   -v server/dir:/path/to/mount/point \   centos