def getClusterInstance(clusterName, serviceInstance):
   """
      Get the cluster MO given the cluster name
   """
   content = serviceInstance.RetrieveContent()
   searchIndex = content.searchIndex
   datacenters = content.rootFolder.childEntity
   for datacenter in datacenters:
      cluster = searchIndex.FindChild(datacenter.hostFolder, clusterName)
      if cluster is not None:
         return cluster
   return None