Summary of Container Hackathon Experiences (D2.8)

Atmosphere and ocean models are characterised by complex dependencies, external configurations, and performance requirements. The objective to containerise such software stacks helps to provide a consistent environment to ensure security, portability and performance. Since the container is built only once, but then can be deployed on multiple platforms, productivity is increased. ETH Zurich (ETHZ) has organised and carried out a "hackathon" (programming session) to help ESiWACE community scientists create containers for their Earth-system models. Seven teams joined the hackathon, and each team was assigned a mentor with extensive container experience. The teams were given the challenge to get as far as they could in containerising their model, and, if possible, to analyse performance at scale on the Piz Daint computing platform at the Swiss National Supercomputing Centre (CSCS). The teams made faster progress on their containers than even we organisers anticipated. Although many of the participants had never created a container previously, every team managed to complete and a run containerised version of its model, and some teams were able to benchmark on hundreds of computing nodes on Piz Daint. This report summarises the experiences made by the individual teams at the hackathon and draws some conclusions about the viability of 'kick-starting' containerisation efforts with such an intense programming event