**Response**

  The response should be a valid HTTP response with a blank or arbitrary body.
  Only the HTTP header information is considered by the requestor. A successful
  response MUST have a HTTP status code of 200. In case of an error condition,
  the appropriate HTTP status code MUST be set, and an exception or error
  information MAY be returned in the response body.

  **Example**

  Example of ping request and response for a Member Node (Coordinating Nodes
  implement the same functionality). Lines prefixed with ">" indicate outgoing
  information, lines prefixed with "<" show content returned from the server.
  Lines associated with SSL connection initiation and close are not shown here.
  Note that the actual response headers may vary, the only required header
  fields are the first status line and a ``Date`` entry. However, in order to
  fully support clients that may cache the response, it is recommended that the
  ``Expires``, and ``Cache-Control`` headers are returned.

  .. code-block:: bash
     :emphasize-lines: 2,11

     export NODE="https://demo2.test.dataone.org/knb/d1/mn"
     curl -k -v "$NODE/v1/monitor/ping"
    
     > GET /knb/d1/mn/v1/monitor/ping HTTP/1.1
     > User-Agent: curl/7.21.6 (x86_64-pc-linux-gnu) libcurl/7.21.6 
       OpenSSL/1.0.0e zlib/1.2.3.4 libidn/1.22 librtmp/2.3
     > Host: demo2.test.dataone.org
     > Accept: */*
     > 
     < HTTP/1.1 200 OK
     < Date: Tue, 06 Mar 2012 14:19:59 GMT
     < Server: Apache/2.2.14 (Ubuntu)
     < Content-Length: 0
     < Content-Type: text/plain
     <