The Decision Engine is a critical component of the HEP Cloud Facility. It provides the functionality of resource scheduling for disparate resource providers, including those which may have a cost or a restricted allocation of cycles
Code documentation, release notes and install instructions are on github.io: https://hepcloud.github.io/decisionengine/
There is a specfic document on this at https://github.com/HEPCloud/decisionengine/blob/master/DEVELOPMENT.md