This ignores the reality that kubernetes came from google and was based on existing (long lived) tooling. Docker is "some shell scripts around namespaces and cg

This ignores the reality that kubernetes came from google and was based on existing (long lived) tooling. Docker is "some shell scripts around namespaces and cgroups" (also long lived, existing tooling). The fact that there is public interest in these things _maybe_ you can attribute in some way to ruby but not the existence of them IMO.