We are using xymon-4.2.2 on rhel 5.2 server and more than 200 clients (HPC Cluster nodes).
Our requirement is :
-> If the node is powered down by scheduler for saving the power, it is required that xymon should show its state as green and same for other tests of same node.
Nodes powered down by scheduler are identified by pbsnodes command which will show state as power.
-> If the node is going down by some other reason other that powering down by scheduler, it should show red like normal clients.
Assuming your scheduler can have shell script hooks attached to events, I'd add something to send a "disable" command before it brings a node down, and then re-enable as it comes back up. If the nodes are being powered down without state being saved (eg, not suspending/resuming themselves), then just disable "until OK", otherwise I'd use some arbitrary future value.
Relevant tests will be blue (not green, as requested), but that will be handled as a non-event for SLA purposes.
Separately, it might be a good idea to have a separate server-side test that sends node state about each node to xymon independent of the node itself. That test is a fine place to put logic as well.
HTH,
-jc