One very interesting tool that Docker makes available is https://store.docker.com/community/images/docker/docker-benc...
I think the issue with k8s is that it is competing with the "Ruby on Rails" of frameworks viz Docker Swarm. I think the pluggability of critical pieces like ingress and secrets was taken too far.
> I doubt very much that you can run a large number of similar apps in a single swarm without having collisions on things like ports.
I dont think that is true, it does manage its overlay networks pretty well. Which is FWIW, another place where k8s took the non-opinionatedness too far. I think the number of bugs on "my stuff doesnt work with flannel but works with calico" should tell you that.
To be honest, Docker Swarm has some of these issues as well - https://github.com/moby/moby/issues/25526. But the fixes are included in the "batteries". On kuberenetes, I have to run behind upstream projects with heterogenous configuration (nginx vs haproxy ingress. or flannel vs calico configuration) to try and fix it.