I've found that both Swarm and k8s - but _especially_ the latter - makes the day-to-day application deployment really smooth compared to almost anything I used

I've found that both Swarm and k8s - but _especially_ the latter - makes the day-to-day application deployment really smooth compared to almost anything I used before (git-deploy, fabric, rsyncing things around). Docker containers are a large part of that, of course, but the tooling and configuration/secret handling help as well.