System testing software deployments using Docker and Kubernetes in gitlab CI: EOS + CTA use case

<!--HTML-->The IT Storage group at CERN develops the software responsible for archiving to tape the custodial copy of the physics data generated by the LHC experiments. This software is code named `CTA` - *CERN Tape Archive*. It needs to be seamlessly integrated with `EOS`, which has become the de facto disk storage system at CERN. `CTA` and `EOS` integration requires parallel development of features in both software that needs to be **synchronized and systematically tested** on a specific distributed development infrastructure for each commit in the code base. This presentation describes the full gitlab continuous integration work flow that builds, tests, deploys and run system tests of the full software stack in docker containers on our specific kubernetes infrastructure.