Paweł Pokrywka's wroclove.rb 2017 talk explaining how to model a distributed application, its infrastructure and infrastructure-management changes, then predict performance shifts (e.g. whether rescaling will actually help) without complex benchmarks, via simulation over the model. Available on YouTube. Two years later at wroclove.rb 2019 he open-sourced the supporting code as a Ruby gem backed by Petri Nets.