Support both virtualbox and libvirt providers in Vagrantfile

Vagrantfile

@@ -10,11 +10,10 @@ Vagrant.configure(2) do |config|
   # Disable synchronization of the /vagrant folder for faster startup.
   config.vm.synced_folder ".", "/vagrant", disabled: true
 
-  # Uncomment to increase RAM to 1G.
-  #config.vm.provider :virtualbox do |vb|
-  #  vb.customize ["modifyvm", :id, "--memory", "1024"]
-  #end
-
+  # Increase RAM to 1G.
+  config.vm.provider :virtualbox do |vb|
+    vb.customize ["modifyvm", :id, "--memory", "1024"]
+  end
   config.vm.provider :libvirt do |libvirt|
     libvirt.memory = 1024
   end
@@ -23,7 +22,7 @@ Vagrant.configure(2) do |config|
   (1..NUM_HOSTS).each do |i|
     config.vm.define "host#{i}" do |m|
       m.vm.hostname = "host#{i}"
-      m.vm.network "private_network", ip: "10.236.82.#{9+i}"
+      m.vm.network "private_network", ip: "10.236.82.#{9+i}", libvirt__dhcp_enabled: false
     end
   end
 end