Docker and Kubernetes. Kubernetes and Docker.

Kubernetes has become the trending orchestration solution for containers. All big Cloud providers bet on it, and even in smaller companies, k8s (written that way as there are 8 letters between k and s) is what all the hip developers go for.
Docker is still used to build all the images, and they have made it to a commercial product used by many customers.
Kubernetes has focused on being an extensible and scalable framework, and is still growing fast; it has a credible reputation for managing data center scale with best possible control. In fact, control is IMHO the word that describes its nature best.
Docker has chosen to put user experience first: it provides rich functionality with sane defaults, but users don't have to think about it -- Docker simply and quickly does what you mean. User experience is (IMHO) Docker's core characteristics.

Docker in the Datacenter

In this year's DockerCon back in April 2017, then-Docker CEO Ben Golub announced Docker will support the mainframe (and Power).

While technically, this is no news, it means Docker, Inc. will support s390x -- good news and another option besides distribution offerings for those looking at running Docker in production on the mainframe. More details to follow as they are announced and available.

DockerCon EU

Should you be at DockerCon Europe 2015 in Barcelona, don't miss to stop by at the IBM booth. I will be there, too (for a cool 10,000 containers demo that the Linux on Power folks prepared, but if you start talking about z Systems, I will of course not stop the discussion).
See you there...