Vagrant nodes with different IPs and RAM

Demonstrate assigning private network interfaces to VMs, in order for them
to communicate with each other. And assigning a different amount of RAM to a
single node. Nodes are defined in a Ruby hash.

VirtualBox provider customisations have been moved into the `nodes.each`
loop because it needs access to `node_opts[:memory]`. There seems to be no
speed impact to `vagrant status`. Whereas calling `customize` twice would
have been significantly slower, even if it did look cleaner.

Vagrantfile

@@ -1,29 +1,40 @@
 # -*- mode: ruby -*-
 # vi: set ft=ruby :
 
-nodes = %w{node0 node1 node2}
+nodes = {
+  'node0' => {:ip => '172.16.10.1', :memory => 512},
+  'node1' => {:ip => '172.16.10.2'},
+  'node2' => {:ip => '172.16.10.3'},
+}
 
 Vagrant.configure("2") do |config|
   config.vm.box     = "precise64"
   config.vm.box_url = "http://files.vagrantup.com/precise64.box"
 
-  config.vm.provider :virtualbox do |vb|
-    modifyvm_args = ['modifyvm', :id]
-    # Isolate guests from host networking.
-    modifyvm_args << "--natdnsproxy1" << "on"
-    modifyvm_args << "--natdnshostresolver1" << "on"
-    vb.customize(modifyvm_args)
-  end
-
   config.vm.provision :puppet do |puppet|
     puppet.manifest_file  = "site.pp"
     puppet.manifests_path = "manifests"
     puppet.module_path    = [ "modules", "vendor/modules" ]
   end
 
-  nodes.each do |node_name|
+  nodes.each do |node_name, node_opts|
     config.vm.define node_name do |node|
       node.vm.hostname = node_name
+
+      if node_opts[:ip]
+        node.vm.network(:private_network, :ip => node_opts[:ip])
+      end
+
+      config.vm.provider :virtualbox do |vb|
+        modifyvm_args = ['modifyvm', :id]
+        if node_opts[:memory]
+          modifyvm_args << "--memory" << node_opts[:memory]
+        end
+        # Isolate guests from host networking.
+        modifyvm_args << "--natdnsproxy1" << "on"
+        modifyvm_args << "--natdnshostresolver1" << "on"
+        vb.customize(modifyvm_args)
+      end
     end
   end
 end