Enforce overlay2 on Debian (#155)

Author: alvaroaleman

pkg/installer/installation/prerequisites.go

@@ -135,6 +135,11 @@ source /etc/os-release
 # Short-Circuit the installation if it was arleady executed
 if type docker &>/dev/null && type kubelet &>/dev/null; then exit 0; fi
 
+sudo mkdir -p /etc/docker
+cat <<EOF |sudo tee /etc/docker/daemon.json
+{"storage-driver": "overlay2"}
+EOF
+
 sudo apt-get update
 sudo apt-get install -y --no-install-recommends \
      apt-transport-https \