harness.xml

<cluster xmlns="http://www.globus.org/2008/06/workspace/metadata/logistics">

 <workspace>
   <name>head-node</name>
   <image>ami-xxxxxxxx</image>
   <quantity>1</quantity>
   <nic wantlogin="true">public</nic>
   <ctx>
     <provides>
       <identity/>
       <role>head-node</role>
     </provides>
     <requires>
       <identity/>
       <role name="worker-node" hostname="true" pubkey="true" />
     </requires>
   </ctx>
 </workspace>

 <workspace>
   <name>worker-node</name>
   <image>ami-xxxxxxxx</image>
   <quantity>1</quantity>
   <nic wantlogin="true">public</nic>
   <ctx>
     <provides>
       <identity/>
       <role>worker-node</role>
     </provides>
     <requires>
       <identity/>
     </requires>
   </ctx>
 </workspace>

</cluster>