If your server needed to scale high (say with scores of provisioning events per minute, or especially low latency), Go's lighter weight would be a selling point. But orchestration is about coordination, often of dissimilar things; that means dealing with different APIs, end-points, and subsystems. I've found Python to be quite good at such tasks. Its higher level nature and well-developed Web frameworks (e.g. Flask, Tornado) seem a good fit.