Use overlay instead of aufs for docker builds to get around singularity whiteout file issue

apt-get update

apt-get install -y docker-ce

# Use overlay2 to get around issues with aufs .wh files blowing up singularity

sudo systemctl stop docker

cat << EOF > /etc/docker/daemon.json

{

  "storage-driver": "overlay2"

}

EOF

sudo systemctl start docker

# Setup firewall

ufw default deny incoming

ufw default allow outgoing