EnjoyHQ

We use collectd because of it's low footprint and great capabilities. We use it to monitor our Google Compute Engine machines. More interestingly we setup collectd as StatsD replacement - all our Clojure services push application-level metrics using our own metrics library and collectd pushes them to Stackdriver

We use Google Compute Engine because it's developer centric, easy to use, yet really powerful. Comparing to AWS (which we originally stared with) it's more approachable, while having no obvious tradeoffs.

We use nginx because it's super reliable, has great extensions and at the same time is light-weigh​t. nginx powers our authorization layer, inter-service communication, and public load balancing (fronted by Google Compute Engine load balancers).

We initially chose RethinkDB because of the schema-less document store features, and better durability resilience/story than MongoDB In the end, it didn't work out quite as we expected: there's plenty of scalability issues, it's near impossible to run analytical workloads and small community makes working with Rethink a challenge. We're in process of migrating all our workloads to PostgreSQL and hopefully, we will be able to decommission our RethinkDB deployment soon.