Swarm level metadata

[jesseops]

I do not currently see any method (nor issues discussing such a method) of adding metadata such as labels or a name to a Swarm cluster.

For instance, I would like to be able to run docker swarm init --name sandbox and docker swarm update --label-add site=$LOCATION.

This would ease management of services that are duplicated across Swarms (eg an application deployed across multiple sites) as well as making it simple to indicate the purpose of a Swarm.

As an example, I have a monitor pushing Swarm/node info from each of my cluster members to a service that normalizes it to information useful for our orchestration/monitoring tooling. Right now I have to derive the site/name/etc from hostnames... Ideally, I would be able to refer to a swarm (or set of swarms) based on name or labels. Any time I bring up a new Swarm I would simply need to create my monitor service and suddenly all of my tooling is aware of the new sandbox or site, etc.