The Renovation of the CERN Controls Configuration Service

The Controls Configuration Service (CCS) is a key component in CERN's data driven accelerator Control System. Based around a central database, the service also provides a range of client APIs and user interfaces - enabling configuration of controls for CERN's accelerator complex. The service has existed for 35 years (29 based on Oracle DBMS). There has been substantial evolution of the CCS over time to cater for changing requirements and technology advances. Inevitably this has led to increases in CCS complexity and an accumulation of technical debt. These two aspects combined have a negative impact on the flexibility and maintainability of the CCS, leading to a potential bottleneck for Control System evolution. This paper describes on-going renovation efforts (started mid-2014) to tackle the aforementioned issues, whilst ensuring overall system stability. In particular, this paper covers architectural changes, the agile development process in place - bringing users close to the development cycle, and the deterministic approach used to treat technical debt. Collectively these efforts are leading towards a successful renovation of a core element of the Control System.