7.5 Grid Computing

Do I need to have a Condor pool installed to use Condor-G?

No, you do not. Condor-G is only the job management part of Condor. It makes perfect sense to install Condor-G on just one machine within an organization. Note that access to remote resources using a Globus interface will be done through that one machine using Condor-G.

I want to install Globus on my Condor pool, and have external users submit jobs into the pool. Do I need to install Condor-G?

No, you do not need to install Condor-G. You need to install Globus, to get the "Condor jobmanager setup package." See the Condor-G homepage at http://www.cs.wisc.edu/condor/condorg/ for a link to Globus.

I am the administrator at Physics, and I have a 64-node cluster running Condor. The administrator at Chemistry is also running Condor on her 64-node cluster. We would like to be able to share resources. Do I need to install Globus and Condor-G?

You may, but you do not have a need to. Condor has a feature called flocking, which lets multiple Condor pools share resources. By setting configuration variables, jobs may be executed on either cluster. Flocking is good (better than Condor-G) because all the Condor features continue to work. Examples of features are checkpointing remote system calls. Unfortunately, flocking only works between Condor pools. So, access to a resource managed by PBS, for example, will still require Globus and Condor-G to submit jobs into the PBS queue.

What is glidein?

Glidein provides a way to temporarily add a Globus resource to a local Condor pool. Condor-G is not required to use glidein. Glidein uses Globus resource-management software to run jobs. It works by executing the portions of Condor software on the Globus resource. Then, Condor may execute the user's jobs. There are several benefits to working in this way. Checkpoints can be made of the jobs running on the Globus resource, and remote system calls can be supported. Condor can also dynamically schedule jobs across the Grid.

See section 5.3.4 of the manual for further information.