The APIs are pretty simple. You could most likely write the orchestration you wanted in a shell script full of calls to curl, or do the same in a nicer scripting language with a decent JSON and http library. I'm working on a very simple orchestrator along the lines for my own needs, as well as a Sinatra application that serves nginx configs to load-balance all the containers running a particular image on a set of hosts.
There are many tools in this space, but it's also not hard to write your own - you're just wiring together some REST APIs.