I have a docker-cloud.yml file that successfully starts a swarm, but it (apparently randomly) selects the nodes that each container runs on. I have associated containers that I want to run in the same node, but I don't see a way to do that.

I don't see the term in Docker, but I otherwise might refer to this as "affinity". I want containers to have assigned node affinity.

I see the add-label command and I see one version of the documentation that indicates a tags: field in the configuration file, but my version of docker doesn't allow that field.

I'm using docker version 17.04.0-ce on Ubuntu 16.04.2 LTS (xenial)