The link you posted highlights my exact concern with Swarm. If I use port 8080, then nobody else can use port 8080. That is a different tradeoff than Kubernetes is willing to make.

Functionally, we have this in NodePort, but because it is exclusively managed, you're very unlikely to have a meaningful conflict. BUT it depends on traffic ingress being managed.

If you just want to map port 8080 on every node into your kube Service, it's more complicated than Swarm. Granted. That's because we don't think you should do that - it doesn't scale.

If you just want to map a port on every node (and you don't care which port), kube Services have you covered. Swarm's model is a nearly-direct clone of this.