The QCG-PilotJob system is designed to schedule and execute many small jobs inside one scheduling system allocation. Direct submission of a large group of jobs to a scheduling system can result in long aggregated time to finish as each single job is scheduled independently and waits in a queue. On the other hand the submission of a group of jobs can be restricted or even forbidden by administrative policies defined on clusters. One can argue that there are available job array mechanisms in many systems, however the traditional job array mechanism allows to run only bunch of jobs having the same resource requirements while jobs being parts of larger workflows by nature vary in requirements and therefore need more flexible solutions.
The core component of QCG-PilotJob system is QCG-PilotJob Manager. From the scheduling system perspective, QCG-PilotJob Manager, is seen as a single job inside a single user allocation. It means that QCG-PilotJob Manager controls an execution of a complex experiment consisting of many jobs on resources reserved for the single job allocation. The manager listens to user’s requests and executes commands like submit job, cancel job and report resources usage. In order to manage the resources and jobs the system takes into account both resources availability and mutual dependencies between jobs. Two interfaces are defined to communicate with the system: file-based (batch mode) and API based. The former one is dedicated and more convenient for a static scenarios when a number of jobs is known in advance to the QCG-PilotJob Manager start. The API based interface is more general and flexible as it allows to dynamically send new requests and track execution of previously submitted jobs during the run-time.
To allow user’s to test their scenarios, QCG-PilotJob Manager supports local execution mode, in which all job’s are executed on local machine and doesn’t require any scheduling system allocation.
QCG-PilotJob’s source code is publicly available at: https://github.com/vecma-project/QCG-PilotJob
QCG-PilotJob consists of three components:
- QCG-PilotJob Core
- the essential part of the software, provides all basic mechanism needed to use QCG-PilotJob
- QCG-PilotJob Command Line Tools
- a set of command line tools for reporting and analysis of QCG-PilotJob execution
- QCG-PilotJob Executor API
- an alternative, simplified API for QCG-PilotJob