Turn off VT-x and limit to 1 CPU

tests/Vagrantfile

@@ -13,7 +13,14 @@ Vagrant.configure(2) do |config|
   config.vm.define "vsrx" do |vsrx|
       vsrx.vm.hostname = "vsrx"
       vsrx.vm.box = "juniper/ffp-12.1X47-D15.4-packetmode"
+
+      vsrx.vm.provider :virtualbox do |vb|
+        vb.customize ["modifyvm", :id, "--hwvirtex", "off"]
+        vb.cpus = 1
       end
+  end
+
+
 
   config.vm.provision "ansible" do |ansible|
       ansible.groups = {