There is a reason that the largest Internet companies are still running their infrastructure on Java and C++. It scales and operations people know how to manage it.

Rails is the classic example of optimizing for developer ease of use instead of performance. Which probably makes sense for startups, but scaling is a pain in the ass.

Openresty is great for infrastructure level solutions, e.g. request routing and authentication. It is used by some of the largest Internet companies in China.

The benchmarks at http://www.techempower.com/benchmarks/ are a reminder of how poorly some popular frameworks perform. And how poorly cloud performs vs relatively cheap dedicated hardware.