Allow docker swarm token to work about cluster-lab

[firecyberice]

@richtong Consul is not only used for swarm but also for docker overlay networks. These networks need a key-value store like consul. How do you manage them in your case with the swarm token?

[richtong]

I would say we do not use overlay when using swarm. Right now for our 40 nodes, we do not use overlays. I was not sure when consul didn't attach whether it was overlays or consul itself that was failing. We have since upgrade to a better (small business vs unmanaged) switch so need to try again, but since swarm doesn't do overlays I'd say we set vlan off when we do swarm.

[firecyberice]

Our DOCKER_OPTS are official docker daemon options where do you find the corresponding flags like swarm-image swarm-advertise etc?
For being smart enough to select the correct images for each supported arch we have https://github.com/hypriot/cluster-lab/blob/master/package/usr/local/bin/cluster-lab#L15-28.