To turn on experimental docker functions create following file by:
sudo nano /etc/docker/daemon.json
and add below content to it
{
"experimental": true
}
and save file (by CTRL+X and Enter ) and exit. In terminal type:
sudo service docker restart
To check that experimental funcions are ON, type in terminal:
docker version
And you should see Experimental: true
UPDATE
Instead of nano you can use this one-liner:
echo $'{\n "experimental": true\n}' | sudo tee /etc/docker/daemon.json