Production ready Mesos hosted in the cloud.
Now I dont have to run a $500M company to cut server costs and save dev ops time. Apache Mesos is a system predominatly used by large companies, to more efficiently utilize servers in their data centers.
The traditional way of organizing your servers requires a certain number of servers per cluster. For example: 50 webservers for your web app in one cluster, 5 servers for your database in another cluster, and 10 servers for redis, etc. On average, you'd utilize 50% of each cluster, but have the extra capacity for spikes.
Mesos makes your servers way more efficient by treating them as raw power, allowing any server to run any kind of app/task. It chops a server up into many linux containers and can shuffle around your tasks, so that a web app, redis server, and database server could all be running in different areas of the same "physical" server. I read that one company saved ~40% of their server costs and served the same load just by switching to Mesos.
Marathon is made by Mesosphere and acts as the brains or controller for your servers. You can allocate what percentage of resources go to certain apps/tasks, and it also handles deployment, scaling, failover and restarting.
Mesos supports Docker, so converting an existing app to run this on DO with Mesosphere is simple. Some applications are built for Mesos already, like Spark (MapReduce replacement), and will be inherently faster without the Docker overhead.
I found Mesosphere's tutorial useful for setting up a dev environment and trying things out - https://mesosphere.com/docs/getting-started/playa-install/