# File lib/deltacloud/drivers/vsphere/vsphere_driver.rb, line 124
    def realms(credentials, opts=nil)
      vsphere = new_client(credentials)
      safely do
        if opts and opts[:id]
          datastore = find_datastore(credentials, opts[:id])
          [convert_realm(datastore)]
        else
          rootFolder = vsphere.serviceInstance.content.rootFolder
          rootFolder.childEntity.grep(RbVmomi::VIM::Datacenter).collect do |dc|
            dc.datastoreFolder.childEntity.collect { |datastore| convert_realm(datastore) }
          end.flatten
        end
      end
    end