Define and implement health roll up policy for software

To avoid re-work, the policy for aggregation and actual meaning of the health indicators need to be agreed before implementation starts.  Health state is one of the key indicators provided by the SKA Tango devices; the  health state indicates overall state of the product, subsystem and/or device, thus providing both human operators and software clients with a simple aggregated indicator.  

Monitoring health state is essential during testing, integration, commissioning and operations.

The policy for the aggregation of health state in the MCCS  agreed and clearly defined and published in the Solution Intent.   The MCCS policy for health aggregation  complies with the SKA policy for state aggregation.

Aggregation of health state  is implemented  by MCCS software - need to agree the scope, i.e. identify the TANGO Devices where the policy will be implemented.

A workshop was held so as to understand the meaning of health and health aggregation, agreeing a way forward. This has been recorded as a Confluence page.
Use of the Python Rules Engine was investigated but in the first instance it was decided to code the logic for determining health into the Devices, with configurable threshold values.
This structure was then implemented across MCCS devices.