private void rpcPreCheck(String requestName) throws ServiceException {
    try {
      checkOpen();
      requirePermission(requestName, Permission.Action.ADMIN);
    } catch (IOException ioe) {
      throw new ServiceException(ioe);
    }
  }
Checks for the following pre-checks in order:
<ol>
<li>RegionServer is running</li>
<li>If authorization is enabled, then RPC caller has ADMIN permissions</li>
</ol>
@param requestName name of rpc request. Used in reporting failures to provide context.
@throws ServiceException If any of the above listed pre-check fails.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RSRpcServices.java