UWMLSC > Beowulf Systems > Medusa

NUTs On The Cluster

How It Works

  • Wiring
    1. A UPS is plugged into the wall outlet via 30 Amp power cable.
    2. The nodes are plugged into power strips which are connected to the UPS.
    3. A serial cable connects the UPS to the server node. The client nodes communicate to the server node across the network.
  • Power Failure
    1. The UPS loses power from the 30 amp outlet.
    2. "On Battery" signal is sent to the UPS server over the serial cable.
    3. UPSD status is changed to "On Battery".
    4. Clients running UPSMON periodically check the status of the UPSD.
    5. If after 2 minutes the status remains "On Battery" the nodes will shutdown.
  • Configuration Notes
    1. upssched.conf is the config file for the timer used in shutting down the nodes. It is located in /etc/ups
    2. If the last message the clients recieve is "On Battery" and the network goes down, the nodes will shutdown after 2 minutes.
    3. Driver file (tripplite), upsmon and upsd are located in /usr/sbin

Diagram of NUTs Setup On the Cluster

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