You are viewing an old version of this page. View the current version.

Compare with Current View Page History

« Previous Version 52 Next »

Open questions:


  • Transfer mechanism: Documenation implies that only files with an mtime newer than when the transfer_input_files finished will be transferred back to the submit host.  While running a dag, the files in my working directory (which is in both transfer_input_files and transfer_output_files) seem to always have an mtime around the most recent step in the DAG suggesting that the entire working directory is copied from the execution host to the submit host at the end of each DAG step.  Perhaps this means the transfer mechanism only looks at the mtime of the files/dirs specified in transfer_output_files and doesn't descend into the directories.

  • Flocking: When we flock to CHTC what are the two points that transfer_input_files?  Is it our submit host and CHTC's execution host?


  • Public_input_files: How is this different than transfer_input files and when would one want to use it instead of files or URLs with transfer_input_files?
  • How can we transfer_input_files faster to our clients.  Currently we assume it will use the 1Gb link but we have IB links.  Should we upgrade to 10Gb?  Is there a way for condor to use the IB link just for transferring files?  Other ideas?

  • Issues running single-node OpenMPI jobs?

  • What does DAGMan do when a process returns an error code (like 1)?  Is there a way DAGMan can be told to ignore errors?


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.
  • Environment:  Is there a way to have condor "login" when a job starts thus sourcing /etc/proflie and the user's rc files? Currently, not even $HOME is set.
    • 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/
    • If data is a symlink (e.g. data → ../data) and transfer_input_files=data then I get the error about won't transfer symlinks to directories
    • if data is a symlink (e.g. data → ../data) and transfer_input_files=data/ then it transfers the contents not the directory.  In other words I don't have a data directory in scratch I have a VLASS... directory.

  • 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.  Negotiator pre-job rank is a third type of rank that works at a pool level and is often used to pack jobs efficiently.


  • Update on software store for CASA either on shared Ceph storage or admin software storage
    • Staging area for datasets 100MB - TBs.  This is where we could try keeping the cfcache assuming doing so doesn't overwhelm the filesystem.
      • /staging/nu_jrobnett
      • Requirements = (Target.HasCHTCStaging == true)
      • Quota: 100GB, 100K files
    • Squid area for 100MB - 1GB input or shared software.  This is where we could keep casa.tgz and then have the execution host retrieve it via HTTP.
      • /squid/nu_jrobnett
      • only accessable via this path on the submit hosts.  Execution hosts will need to access it via HTTP.
      • transfer_input_files = http://proxy.chtc.wisc.edu/SQUID/nu_jrobnett/casa.tgz

    • Software area We can use this in run-time applications.  Think of it like /usr/local.




  • No labels