...

• • A good analogy is Torque does a su - _username_ while HTCondor just does a su _username_
  • WORKAROUND: setting getenv = True which is like the -V option to qsub, may help. It doesn't source rc files but does inherit your current environment. This may be a problem if your current environment is not what you want on the cluster node. Perhaps the cluster node is a different OS or architecture.
  • ANSWER: condor doesn't execute things with a shell.  You could set your executable as /bin/bash and then have the arguments be the executable you used to have.  I just changed our stuff to staticly set $HOME and I think that is good enough.
    
    
• Flocking: Suppose I have two hosts in the same pool.  testpost-master is a submit-host and testpost-serv-1 is both a submit-host and the central-manager.  testpost-serv-1 is configured to flock to CHTC but testpost-master is not. Is it possible to submit a job on testpost-master that will flock to CHTC by somehow leveraging testpost-serv-1?  In other words, do I have to setup flocking and an external IP on every submit host?
  • ANSWER: there isn't a good way to do this.  So eventually we will need to make testpost-master flock to CHTC and possibly remove the ability of testpost-serv-1 to flock.
    
    
• It seems the transfer mechanism won't transfer symlinks to directories (e.g. data/vlass.ms → /lustre/aoc/...) Is there a way around this?
  • ANSWER: there is no flag to chase symlinks at the moment.  The top level dir (e.g. data) could be a symlink  may work if transfer_input_files=data/
    
    
• DAG log time stamps,  is there a way to differentiate data import/export time and process run time.
  • Look in the job log file not the dag log file
  • 040 (150.000.000) 2020-06-15 13:05:45 Started transferring input files
            Transferring to host: <10.64.10.172:9618?addrs=10.64.10.172-9618&alias=nmpost072.aoc.nrao.edu&noUDP&sock=slot1_1_72656_7984_60>
    ...
    040 (150.000.000) 2020-06-15 13:06:04 Finished transferring input files
    
    
    
• Rank and Premption: Can we use Rank to set "preferences" without requiring job preemption?
  • ANSWER: There are 2 kinds of rank (job rank, machine rank).  job rank (RANK=... in a submit file) is purely a preference.  That does not preempt.  Machine rank (in startd.config) will preempt.
    
    

Answered Questions:

• JOB ID question from Daniel

  • When I submit a job, I get a job ID back. My plan is to hold onto that job ID permanently for tracking. We have had issues in the past with Torque/Maui because the job IDs got recycled later and our internal bookkeeping got mixed up. So my questions are:

     - Are job IDs guaranteed to be unique in HTCondor?
     - How unique are they—are they _globally_ unique or just unique within a particular namespace (such as our cluster or the submit node)?

  • A Job ID (ClusterID.ProcID)
  • DNS name of the schedd and ctime of the job_queued.log file.
  • It is unique to a schedd.
  • We should talk with Daniel about this.  They should craft their own ID.  It could be seeded with a JobID but should not depend on just it.
• UpgradingHTCondor without killing jobs?
  • schedd can be upgraded and restarted without loosing state assuming the restart is less than the timeout.
  • currently restarting execute services will kill jobs.  CHTC is working on improving this.
  • negotiator and collector can be restarted without killing jobs.
  • CHTC works hard to ensure 8.8.x is compatible with 8.8.y or 8.9.x is compatible with 8.9.y.
• Leaving data on execution host between jobs (data reuse)
  • Todd is working on this now.
• Ask about installation of CASA locally and ancillary data (cfcache)
  • CHTC has a Ceph filesystem that is available to many of their execution hosts (notibly the larger ones)
  • There is another software filesystem where CASA could live that is more used for admin usage but might be available to us.
  • We could download the tarball each time over HTTP.  CHTC uses a proxy server so it would often be cached.