[koffiezet]

A lot of the (performance) problems are probably caused by the device mapper backend being used on CentOS... I have no performance issues at all running in production on Ubuntu 14.04 using aufs.

> The slowness of Docker is a big pain. Build and deployment procedures are not predictable.

I have the absolute opposite experience. My build & deployment has become very predictable, and I build pretty much all the images I use myself.

> Data belongs onto the filesystem but not into a container that can neither be cloneed in an easy way nor incrementally backed up in a reasonable way. Containers are for software, not for data.

Volumes are for data. And sure they can be backed up or cloned, just launch a container that only backs up mounted volumes with --volumes-from whatever stuff you want to back up. Containers should be stateless, and yes, volumes need more attention.

This whole thing smells like "I tried this tool and I don't fully understand it so I'll write a rant blog about it". Containers force you to think differently about software deployment. I started using Docker very early-on and I have never regretted putting it in production since the 0.6x days.