GSoC 2020: JAliEn Replica Service

Contributor: Animesh Narayan Dangwal
Description Presentation    Blogpost   Project repository

JAliEn, a successor to the AliEn framework, with extended capabilities is being developed and extensively tested in preparation for the next LHC run. This framework will be deployed on a set of Central Services as well as on more than 80 individual computing sites, which provide CPU and storage resources for ALICE. To ease development and give individual developers a robust local development framework with all the necessary capabilities, the core of the JAliEn system (JCentral) must be deployed individually, on a single host, with all necessary configurations. This Google Summer of Code (GSoC) project aimed to develop a command line utility for JAliEn developers to quickly start, develop and tear down JCentral replicas locally. The following section outlines the principle components that were developed as part of this project.


Diagram 1 shown below summarises the developed replica services for both Central Services and a Grid site all running within just 5 containers. JCentral-dev is configured to act as the Central Services with pre-configured authentication and setup. JCentral-dev-SE deploys the site Storage Element (SE) XRootD instance and JCentral-dev-CE is a Computing Element (CE) through which Central Services submit jobs to the Grid. All these containers bind mount into jalien-dev folder from local file system allowing for live debugging and development within a running system. Finally, HTCondor Central Manager and worker are deployed as a dependency to be able to run jobs in a Grid-like environment locally.

Replica of JAliEn Central Services
Diagram 1: Containerised Replica of JAliEn Central Services