We use a combination of tools/languages to reap the same benefits of Erlang. Erlang is designed with some very static assumptions in mind. Nodes aren't really supposed to go down, and upgrades happen in place. This is counter to how modern deployments seem to be heading with rolling restarts and super ephemeral services. So using Erlang was really cutting against the grain of where the industry was heading, and Kubernetes is giving us the same end result of high availability and horizontal scaling.