Add VM README

Author: ccascone

util/vm/.gitignore

@@ -1,2 +1,3 @@
 *.log
 .vagrant
+*.ova

util/vm/README.md

@@ -0,0 +1,27 @@
+# Scripts to build the tutorial VM
+
+## Requirements
+
+- [Vagrant](https://www.vagrantup.com/) (tested v2.2.5)
+- [VirtualBox](https://www.virtualbox.org/wiki/Downloads) (tested with v5.2.32)
+
+## Steps to build
+
+If you want to provision and use the VM locally on your machine:
+
+    cd util/vm
+    vagrant up
+
+Otherwise, if you want to export the VM in `.ova` format for distribution to
+tutorial attendees:
+
+    cd util/vm
+    ./build-vm.sh
+
+This script will:
+
+1. provision the VM using Vagrant;
+2. reduce VM disk size;
+3. generate a file named `ngsdn-tutorial.ova`.
+
+Use credentials `sdn`/`rocks` to log in the Ubuntu system.

util/vm/export.sh util/vm/build-vm.shutil/vm/export.sh renamed to util/vm/build-vm.sh

@@ -2,13 +2,11 @@
 
 set -xe
 
-DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
-
 function wait_vm_shutdown {
     set +x
     while vboxmanage showvminfo $1 | grep -c "running (since"; do
-    echo "Waiting for VM to shutdown..."
-    sleep 1
+      echo "Waiting for VM to shutdown..."
+      sleep 1
     done
     sleep 2
     set -x
@@ -18,7 +16,7 @@ function wait_vm_shutdown {
 vagrant up
 
 VB_UUID=$(cat .vagrant/machines/default/virtualbox/id)
-VBoxManage snapshot ${VB_UUID} take "pre-cleanup"
+VBoxManage snapshot "${VB_UUID}" take "pre-cleanup"
 
 # Cleanup
 vagrant ssh -c 'bash /vagrant/cleanup.sh'