@PUT
  @Path("{groupId}")
  @Produces(MediaType.TEXT_PLAIN)
  @ApiOperation(value = "Updates a config group")
  @ApiImplicitParams({
    @ApiImplicitParam(dataType = CONFIG_GROUP_REQUEST_TYPE, paramType = PARAM_TYPE_BODY)
  })
  @ApiResponses({
    @ApiResponse(code = HttpStatus.SC_OK, message = MSG_SUCCESSFUL_OPERATION),
    @ApiResponse(code = HttpStatus.SC_ACCEPTED, message = MSG_REQUEST_ACCEPTED),
    @ApiResponse(code = HttpStatus.SC_BAD_REQUEST, message = MSG_INVALID_ARGUMENTS),
    @ApiResponse(code = HttpStatus.SC_UNAUTHORIZED, message = MSG_NOT_AUTHENTICATED),
    @ApiResponse(code = HttpStatus.SC_FORBIDDEN, message = MSG_PERMISSION_DENIED),
    @ApiResponse(code = HttpStatus.SC_INTERNAL_SERVER_ERROR, message = MSG_SERVER_ERROR),
  })
  public Response updateConfigGroup(String body, @Context HttpHeaders
    headers, @Context UriInfo ui, @PathParam("groupId") String groupId) {
    return handleRequest(headers, body, ui, Request.Type.PUT,
      createConfigGroupResource(m_clusterName, groupId));
  }
Handles PUT /clusters/{clusterId}/config_groups/{groupId}
Update a config group

@param body
@param headers
@param ui
@param groupId
@return
ambari-server/src/main/java/org/apache/ambari/server/api/services/ConfigGroupService.java