private void setResponseHeader(final HttpServletResponse response) {
    response.setContentType(CONTENT_TYPE_JSON_UTF8);
    response.setHeader(ACCESS_CONTROL_ALLOW_METHODS, ALLOWED_METHODS);
    response.setHeader(ACCESS_CONTROL_ALLOW_ORIGIN, "*");
  }
A servlet to print system specific configurations that are not exposed via JMX.
Currently it exposes
- kernel configs
- network configs
- memory configs

/system?refresh=true will run sysctl command again
llap-server/src/java/org/apache/hadoop/hive/llap/daemon/services/impl/SystemConfigurationServlet.java