<value>
  <id>8db08c68-bc70-11e4-a8c4-fa163e1d1a9b</id>
  <meter>instance</meter>
  <type>gauge</type>
  <unit>instance</unit>
  <volume>1.0</volume>
  <user_id>efd87807-12d2-4b38-9c70-5f5c2ac427ff</user_id>
  <project_id>35b17138-b364-4e6a-a131-8f3099c5be68</project_id>
  <resource_id>bd9431c1-8d69-4ad3-803a-8d4a6b89fd36</resource_id>
  <source>openstack</source>
  <timestamp>2015-02-24T22:00:32.747930</timestamp>
  <recorded_at>2015-02-24T22:00:32.747930</recorded_at>
  <metadata>
    <item>
      <key>name2</key>
      <value>value2</value>
    </item>
    <item>
      <key>name1</key>
      <value>value1</value>
    </item>
  </metadata>
</value>