PanDA Pilot
The PanDA Pilot has been used by ATLAS and other experiments for well over a decade. To meet the demands of extending PanDA beyond grids and ATLAS, the original Pilot (henceforth referred to as Pilot 1) was rewritten and Pilot 2 was born.
The task of the PanDA Pilot is to monitor and execute work units on a worker node, either on the job or event level. On the job level, the work unit is a payload that a user or production system wants to execute. The payload has certain requirements, e.g. input and output files, that are staged by the Pilot, and needs a working environment (incl. containers) that is setup by the Pilot. On the event level, the Pilot launches and feeds a payload with event ranges (a set of events to be processed) downloaded from a server.
The PanDA Pilot is executed on the worker nodes on local resources, on grids and clouds, on HPCs and on volunteer computers. It is downloaded and run by wrapper scripts that are sent by Pilot factories to the worker nodes via batch systems. A Pilot interacts with the PanDA server either directly, via a local instance of the ARC Control Tower (a job management framework used on Nordugrid) or with the resource-facing Harvester service (which provides resource provisioning and workload shaping).
