M #-: Fix and document vcenter_driver.default

src/vmm_mad/remotes/lib/vcenter_driver/vcenter_driver.default

@@ -1,6 +1,13 @@
+<!-- Only the settings explicitly described in this file can be used -->
 <VCENTER>
  <VM>
    <TEMPLATE>
+     <!-- Used in every attach nic operation (including managed nics).
+         Also the following NIC values can be assigned a default:
+            INBOUND_PEAK_BW
+            OUTBOUND_PEAK_BW
+            INBOUND_AVG_BW
+            OUTBOUND_AVG_BW -->
      <NIC>
        <MODEL>vmxnet3</MODEL>
      </NIC>
@@ -8,9 +15,12 @@
  </VM>
  <IMAGE>
    <TEMPLATE>
+     <!--DEV_PREFIX is only used at the time of importing vCenter images -->
      <DEV_PREFIX>sd</DEV_PREFIX>
-     <VCENTER_DISK_TYPE>thin</DISK_TYPE>
-     <VCENTER_ADAPTER_TYPE>lsiLogic</ADAPTER_TYPE>
+     <!-- Disk and Adapter types are only used when creating new image in
+          vCenter from OpenNebula -->
+     <VCENTER_DISK_TYPE>thin</VCENTER_DISK_TYPE>
+     <VCENTER_ADAPTER_TYPE>lsiLogic</VCENTER_ADAPTER_TYPE>
    </TEMPLATE>
  </IMAGE>
 </VCENTER>