Switch Docker to use Overlay2 FS instead of the default (used on Ubuntu Trusty and Xenial [systemd])

overlay2.sh

# First, make sure you're using systemd and
# the prerequisites are fulfilled:
# https://docs.docker.com/engine/userguide/storagedriver/overlayfs-driver/#prerequisites

if [ "$EUID" -ne 0 ]
  then echo "Please run as root"
  exit
fi

mkdir -p /etc/systemd/system/docker.service.d
export DOCKER_START_COMMAND=$(awk -F "=" '/ExecStart/ {print $2}' /lib/systemd/system/docker.service)
export DOCKER_STORAGE_CONFIG_FILE=/etc/systemd/system/docker.service.d/storage.conf
cat > $DOCKER_STORAGE_CONFIG_FILE <<- EOM
[Service]
ExecStart=
EOM
echo "ExecStart=${DOCKER_START_COMMAND} -s overlay2" >> $DOCKER_STORAGE_CONFIG_FILE
systemctl daemon-reload
systemctl restart docker
systemctl status --full docker
#docker info
#rm -r /var/lib/docker/aufs