Docker-machine automounts the users directory… But sometimes that just isn’t enough.

I don’t know about docker 1.6, but in 1.8 you CAN add an additional mount to docker-machine

Add Virtual Machine Mount Point (part 1)

CLI: (Only works when machine is stopped)

VBoxManage sharedfolder add <machine name/id> --name <mount_name> --hostpath <host_dir> --automount

So an example in windows would be

/c/Program\ Files/Oracle/VirtualBox/VBoxManage.exe sharedfolder add default --name e --hostpath 'e:\' --automount

GUI: (does NOT require the machine be stopped)

1. Start “Oracle VM VirtualBox Manager”
2. Right-Click <machine name> (default)
3. Settings…
4. Shared Folders
5. The Folder+ Icon on the Right (Add Share)
6. Folder Path: <host dir> (e:)
7. Folder Name: <mount name> (e)
8. Check on “Auto-mount” and “Make Permanent” (Read only if you want…) (The auto-mount is sort of pointless currently…)

Mounting in boot2docker (part 2)

Manually mount in boot2docker:

1. There are various ways to log in, use “Show” in “Oracle VM VirtualBox Manager”, or ssh/putty into docker by IP address docker-machine ip default, etc…
2. sudo mkdir -p <local_dir>
3. sudo mount -t vboxsf -o defaults,uid=`id -u docker`,gid=`id -g docker` <mount_name> <local_dir>

But this is only good until you restart the machine, and then the mount is lost…

Adding an automount to boot2docker:

While logged into the machine

1. Edit/create (as root) /mnt/sda1/var/lib/boot2docker/bootlocal.sh, sda1 may be different for you…

2. Add

   mkdir -p <local_dir>
   mount -t vboxsf -o defaults,uid=`id -u docker`,gid=`id -g docker` <mount_name> <local_dir>
   

With these changes, you should have a new mount point. This is one of the few files I could find that is called on boot and is persistent. Until there is a better solution, this should work.

---

Old method: Less recommended, but left as an alternative

• Edit (as root) /mnt/sda1/var/lib/boot2docker/profile, sda1 may be different for you…

• Add

  add_mount() {
    if ! grep -q "try_mount_share $1 $2" /etc/rc.d/automount-shares ; then
      echo "try_mount_share $1 $2" >> /etc/rc.d/automount-shares
    fi
  }
  
  add_mount <local dir> <mount name>
  

As a last resort, you can take the slightly more tedious alternative, and you can just modify the boot image.

• git -c core.autocrlf=false clone https://github.com/boot2docker/boot2docker.git
• cd boot2docker
• git -c core.autocrlf=false checkout v1.8.1 #or your appropriate version
• Edit rootfs/etc/rc.d/automount-shares

• Add try_mount_share <local_dir> <mount_name> line right before fi at the end. For example

  try_mount_share /e e
  

  Just be sure not to set the to anything the os needs, like /bin, etc…

• docker build -t boot2docker . #This will take about an hour the first time 🙁
• docker run --rm boot2docker > boot2docker.iso
• Backup the old boot2docker.iso and copy your new one in its place, in ~/.docker/machine/machines/

This does work, it’s just long and complicated

docker version 1.8.1, docker-machine version 0.4.0