[gravypod]

I've used Spark in prod. Worked great and was the highest QPS service in the company I worked at. It was pushing >5GB/hour of JS over ~50 running containers at more than ~1000QPS/container each doing a bunch of crypto (AES) & and data wrangling (JDBC). Only thing that was difficult was serving SSL but that was the Java SSL-key ecosystem's fault. Ideally SSL would come from an edge load balancer but this company had a strange requirement that there was no 80 traffic.