I'm interested in using Datastax's OpsCenter Enterprise in AWS, and following the install instructions here. I need some advice on how large of instance I need to run OpsCenter. I was considering a t2.medium instance, but concerned that is too small. Any advice appreciated.
It depends on how many machines are you going to manage with OpsCenter, but t2.medium should be a good start. If you have a bunch of large-ish clusters (50-100+ nodes), consider switching to m3.large or m3.xlarge, depending on how much memory OpsCenter uses.