Docker swarm is relatively new and not really fit for production, IMHO. Take a look at their support issues on GitHub, it just doesn't work. I think Docker Swarm will be in a good shape, probably six months from now.
Kubertnetes (along with Google Container Engine) is extremely good, having been around the block for a while.
My favourite Orchestrator however has to be DC/OS https://mesosphere.com/product/ (it takes a while to get started, but once you have the hang of it, you really have control of things and it hardly ever fails). Their support community on slack is online all the time and they help you out, always!
If you do not really want to deal with all the orchestration manually, go with AWS'S ECS (It's extremely easy to use, are you already using it?)
Siddarthan Sarumathi Pandian
Full Stack Dev at Agentdesks | Ex Hashnode | Ex Shippable | Ex Altair Engineering