What is a Compute Element?
An OSG Compute Element (CE) is the entry point for the OSG to your local resources: a layer of software that you install on a machine that can submit jobs into your local batch system. At the heart of the CE is the job gateway software, which is responsible for handling incoming jobs, authorizing them, and delegating them to your batch system for execution. Historically, the OSG only had one option for a job gateway solution, Globus Toolkit’s GRAM-based gatekeeper, but now offers the HTCondor CE as an alternative.
Today in OSG, most jobs that arrive at a CE (called grid jobs) are not end-user jobs, but rather pilot jobs submitted from factories. Successful pilot jobs create and make available an environment for actual end-user jobs to match and ultimately run within the pilot job container. Eventually pilot jobs remove themselves, typically after a period of inactivity.
What is HTCondor CE?
HTCondor CE is a special configuration of the HTCondor software designed to be a job gateway solution for the OSG. It is configured to use the JobRouter daemon to delegate jobs by transforming and submitting them to the site’s batch system.
The OSG twiki has more information about the specifics of how the HTCondor CE operates and information on installing and configuring one.
This page was updated on Dec 19, 2018 at 07:00 from htcondor-compute-element.md.