Not sure if this issue is in boot2docker or docker, and if docker support to mount a folder which is link.
If the mount folder is link:
mkdir /app/datadir
ln -s /app/datadir /home/datadir
docker run -d -v /home/datadir:/var/lib/mysql --name mysql mysql:5.7.7
get this error:
FATA[0000] Error response from daemon: Could not create local directory '/home/datadir' for bind mount: mkdir /home/datadir: file exists!
If I mount with /app/datadir, it is fine.
My env:
$ boot2docker version
Boot2Docker-cli version: v1.6.0
Git commit: 9894ae9
$ docker version
Client version: 1.6.0