Environment Monitor

The environment monitor is positioned to read the temperature and humidity via a sensor mounted above the rack containing the correlator nodes. It has the ability to generate notifications when the registered temperature or humidity exceed thresholds. The device is at IP and has the DNS name of usno-envmon.

The device is a NetBotz Rack Monitor 200 from APC. The device identifies itself as:

       About System

        Model Number      : NBRK0200
        Serial Number     : ZA1211022826
        Manufacture Date  : 03/10/2012
        Hardware Revision : 05
        MAC Address       : 00 C0 B7 61 61 36
        Flash Type        : AMD A29DL322DB



  • Log into the the envmon by doing telnet usno-envmon. The username and password are the same as the PDUs but must be obtained by contacting an administrator.

  • The terminal interface is a bit painful to use but appears to be functional and self-documenting; see the VNC access described below for a bit higher-level UI.


  • From a production cluster box simply launch a browser. The Linux browser konqueror seems to work while Firefox does not; this might be due to Firefox forcing the use of https rather than http with https access somehow not working with the various security settings.

  • Open the envmon host and it'll offer a name/password page to allow access. Use the usual PDU name and password.


The temperature and humdity data can be retrieved from the device via SNMP. The two values are accessed via SNMP OIDs:

  • Temperature (Fahrenheit):"
  • Humidity (percent):

There are python tools and shell tools that can be used together with the OIDs to get the current readings (a USNO request).

-- JimJacobs - 2019-02-04
Topic revision: r4 - 2021-01-11, JimJacobs
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