Crunch discountConfiguredRAMPercent math seems surprising, undesirable
discountConfiguredRAMPercent was added to a-d-c in #12199, 80da19707253af74bd78c374bfcab64b04d2dbde. The commit message says "Derate advertised node sizes by 5%." What it actually does is increase a container request's RAM requirement by 5% after
ReserveExtraRAM and local keepstore requiprements have been rolled in. Neither seems like what we want: while it's true Crunch won't be able to use all the RAM on the system, the amount it can't use seems likely to be mostly constant based on what else runs from the compute node image rather than a percentage of node size.
We already have a configuration knob,
Containers.ReserveExtraRAM, that lets the administrator tell Crunch that amount. I think we should rely on that exclusively for the goal we're trying to accomplish here, and eliminate
discountConfiguredRAMPercent as a source of difficult-to-diagnose "why didn't my container request get the node size I expected" problems.