Speaker
Description
The stellarator Wendelstein 7-X (W7-X) is a fusion device designed for steady state operation. It is a
complex technical system. To cope with the complexity a modular, component-based control and
data acquisition system has been developed.
During operation phases of W7-X components steadily evolve. For instance measurement devices for
diagnostics get improved, technical processes are optimized, experienced limits of the machine have
to be taken into account or simple “bug fixing” is done. This requires continuous further
development of the components while operating them at W7-X – a typical use case for DevOps
practices.
DevOps is a software engineering practice. The term is a compound of development and operations.
It aims at shorter development cycles, while the quality of the changed system must stay at a high
level. This is achieved by using a highly automated tool chain.
DevOps at W7-X does not (only) mean deploying new software packages. It also comprises setting up
new configurations, changing rules and constraints, improving experiment planning views etc. of
components, based on new scientific and technical experiences. One crucial step of the DevOps tool
chain at W7-X is the release and reconcile process. It is a well defined and automated process that
commits a change in the components configuration (Release) to the control and data acquisition
system with minimal impact. During the process all existing experiment programs are adapted to
this change (Reconcile). For newly added configuration parameters default values are added. Thus it
is guaranteed that experiment programs are still executable at W7-X. The quality is ensured by
preceding unit and integration test, configuration consistency and version checks.
