imple "OK" status.  If the request fails,
 then the PingRequestHandler will respond back with the
 corrisponding HTTP Error code.  Clients (such as load balancers)
 can be configured to poll the PingRequestHandler monitoring for
 these types of responses (or for a simple connection failure) to
 know if there is a problem with the Solr server.
 </p>

 <pre class="prettyprint">
 &lt;requestHandler name="/admin/ping" class="solr.PingRequestHandler"&gt;
   &lt;lst name="invariants"&gt;
     &lt;str name="qt"&gt