The real gem of the Mesos ecosystem was the much lesser known Singularity scheduler from HubSpot.

https://github.com/HubSpot/Singularity

I've run this at scale, in production since 2015 and it has been absolutely rock solid and does most of the production things you'd want. Unlike commercial products, it was written to run HubSpot's own infrastructure so it does what a production system needs. Really bummed to have to downgrade to something like K8s in the near future.