16.0 Green computing > How-to's > Choosing which nodes Moab powers on or off

Conventions

16.3 Choosing which nodes Moab powers on or off

To choose which nodes Moab powers on or off

  1. Set a GREENPOOLPRIORITYF function to describe which order nodes should be selected for power on/off actions. GREENPOOLPRIORITYF uses the PRIORITY node allocation policy options and syntax.

    GREENPOOLPRIORITYF '10*RANDOM'

    This tells Moab to randomly choose a node to power on to meet workload demands, and to randomly choose an idle node to power off to meet the MAXGREENSTANDBYPOOLSIZE goal.

To choose which nodes Moab allocates jobs to

  1. Set a PRIORITY node allocation policy that uses power as the major factor. This causes Moab to allocate jobs to nodes that are already powered on. When no nodes are available to meet this policy, Moab uses the GREENPOOLPRIORITYF function to turn on nodes that are powered off.

    NODEALLOCATIONPOLICY  PRIORITY
    NODECFG[DEFAULT] PRIORITYF='10000*POWER + 10*RANDOM'

    The nodes with the highest priority for workload are the nodes that are powered on. After that, Moab randomly allocates workload.

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