labs: option to set number of vCPUs for each node

Currently, all nodes get the default number of vCPUs (1). With this
patch, the number of vCPUs can be set in a node's configuration
file.

For the compute node, we set the number of vCPUs to 2.

Change-Id: I137be612bc6cb8f2d31adfd756404a9c6349e3c5
Implements: blueprint openstack-training-labs

labs/config/config.compute

@@ -10,3 +10,6 @@ FOURTH_OCTET=53
 NET_IF_0=nat
 NET_IF_1=MGMT_NET
 NET_IF_2=DATA_NET
+
+# Override number of virtual CPUs (default is 1)
+VM_CPUS=2

labs/lib/osbash/virtualbox.functions

@@ -291,6 +291,12 @@ function vm_mem {
     $VBM modifyvm "$NAME" --memory "$MEM"
 }
 
+function vm_cpus {
+    local NAME="$1"
+    local CPUS="$2"
+    $VBM modifyvm "$NAME" --cpus "$CPUS"
+}
+
 # Port forwarding from host to VM (binding to host's 127.0.0.1)
 function vm_port {
     local NAME="$1"

labs/lib/osbash/virtualbox.install_node

@@ -50,6 +50,9 @@ function vm_build_node {
     # Set VM_MEM in config/config.NODE_NAME to override
     vm_mem "$NODE_NAME" "${VM_MEM:-512}"
 
+    # Set VM_CPUS in config/config.NODE_NAME to override
+    vm_cpus "$NODE_NAME" "${VM_CPUS:-1}"
+
     _vbox_configure_ifs
 
     # Port forwarding