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Re: [HTCondor-users] best way to use cached data
- Date: Tue, 11 Dec 2012 16:23:40 -0500
- From: Ian Chesal <ichesal@xxxxxxxxxxxxxxxxxx>
- Subject: Re: [HTCondor-users] best way to use cached data
On Tuesday, 11 December, 2012 at 12:25 PM, Dimitri Maziuk wrote:
It seems we're using slightly different definitions of "simple". Mine is
'Requirements = `[ -f /tmp/cache/subsetXYZ123 ]` == 0'
Indeed. My simple is based in reality and actually works. :)
What you're writing up there is syntactically nice, but requirements expressions are evaluated in the context of the machine ads on the negotiator during matchmaking. They don't have access to the target machine's local disk. Technically, what you're asking for with that syntax isn't possible. And you probably wouldn't want to have to eval [ -f /some/file] for all the machines in your pool just to find a match. It would be very, very slow for anything but a small pool.
What I gave you though is a way to advertise key bits of knowledge about what's on disk in the machine's classad so it's available at negotiation time.
(Plus you glossed over the part where condor somehow knows that
"my_cache_contents.config" today and "his_cache_contents.config" tomorow
are all part condor_config.
Sorry, I don't know how much HTCondor you know. But if you ask I can backfill the answer.
And snipped the bit where I said "does not
need privileges to" mess with system daemons -- but those are minor
You don't need to give any sort of sudo access to users to make this work. They need file system-level permissions to make those config files in a common config directory and then they need Condor-level permissions to be able to issue the condor_reconfig command to put those changes in to effect. The config you want to set is:
ALLOW_ADMINISTRATOR = $(FULL_HOSTNAME)
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