Re: [HTCondor-users] best way to use cached data

[Todd Tannenbaum <tannenba@xxxxxxxxxxx>]

On 12/9/2012 11:36 PM, John Wong wrote:

> I tried to run a script to read a file on the slave machine, but condor
> couldn't read it even if it has full privilege. I think condor runs
> every job in an isolated environment?

Overall, I think Ian Chesal's recent post gave good advice (as usual, 
thanks Ian!) on how to accomplish what you want.

But I wanted to give a quick response on the "condor runs every job in 
an isloated environment" question above.  HTCondor may run the job as a 
different user than the submit user, but I think you were already aware 
of that.  So as Ian implies, if Job A leaves files behind in /tmp that 
are world-readable than a subsequent job can read them, *but* only if 
you are not sandboxing directories like /tmp via the spiffy 
MOUNT_UNDER_SCRATCH knob that appeared in HTCondor v7.7.x and works on 
RHEL 5.x Linux and newer systems.  By default, I don't think anything in 
the filesystem gets sandboxed beyond having the current working 
directory of the job in its own private space, but if you for instance have
  MOUNT_UNDER_SCRATCH = /tmp
in your config file, then each job has its own private "/tmp" that is 
destroyed when the job completes.

See
http://research.cs.wisc.edu/htcondor/manual/v7.8/3_3Configuration.html#18445

regards,
Todd