Why is Puppet Labs moving all their server-side applications to Clojure? In a word - results. Drastic improvements in performance. Increased scalability. Ease of deployment. In several more words - the power and ecosystem of the JVM, Clojure’s functional strengths of immutability and concurrency, and an active development community. Leveraging their Trapperkeeper library, an open source Clojure framework for composing large-scale applications, Puppet Labs has enabled any organization to up their game for building highly reliable long-running applications and services.