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RE: [Condor-users] Specifying the Condor Version in the submit

Well..... there is this not-so-well-documented feature of doing some magic to the classads, which might be of use to you.

It’s the concept of classad-shared-libraries, where you can define custom functions that can be used as classad expressions.



Machine Ad:-


Memory = 1024

Arch = “INTEL”

OpSys = “LINUX”


Job Ad:-


Requirements = Arch == “INTEL” && OpSys == “LINUX” && memoryIsGreaterThan(1000)



Now the function memoryIsGreaterThan() is written in C, which would include the header file “classad_shared.h” & linked as...

$ gcc -fPIC -shared -o libshared.so shared.C


The condor config file should contain this config value...

CLASSAD_LIB_PATH = /path/to/libshared.so


Along these lines, you could write your own function ‘versionIs()’, which would essentially do a substring-check so you could write...

Requirements = versionIs(target.CondorVersion,”6.7”)


I’ve attached the header file “classad_shared.h” & the file with example shared-library-classad functions.


I suspect this is not a widely used feature (going by the fact that, there is no trace of documentation) because there would be calls to dlopen() to load this shared library each time this function is encountered in a classad, making it a not-so-efficient operation.

Another, huge issue would be security, as the code in the shared source segment could be potentially malicious and this would effectively be linked with a condor-daemon with root-level privileges


Lemme know, if you have more questions about using this feature.




Swaroop Sayeram

Member of Technical Staff

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-----Original Message-----
From: condor-users-bounces@xxxxxxxxxxx [mailto:condor-users-bounces@xxxxxxxxxxx] On Behalf Of Ian Chesal
Sent: Tuesday, July 05, 2005 12:29 PM
To: Condor-Users Mail List
Subject: RE: [Condor-users] Specifying the Condor Version in the submit


> >   The machines are still locking when Condor hits a bad machine

> running

> > 6.6.9

> > Is there a way I can tell jobs to only run on the 6.6.10 machines?

> > I have searched the manual and the previous posts and have not found

> > anything.


> Anything that appears in the ClassAd of a startd can be used in the

> requirements _expression_ in your submission ticket. So:


> requirements = CondorVersion == "$CondorVersion: 6.6.10 Apr 27 2005 $"


> NB: I faked that example -- I have 6.7.x running here so the exact

> string you should use to match only 6.6.10 machines needs to be

> determined at your site.


Actually, this got me thinking that a better way to match versions would

be if the version information was separated out into major, minor and

minor-minor attributes like this:


      CondorVersionMajor = 6

      CondorVersionMinor = 7

      CondorVersionMinorMinor = 7


Then I could say, "Run on all 6.7.x machines" with:


requirements = condorversionmajor == 6 && condorversionminor == 7


Or, "Run on only machines with 6.7.5 or higher" with:


requirements = condorversionmajor == 6 && condorversionminor == 7 &&

condorversionminorminor >= 5


Which is a level of version control not capable with the string format

currently used to indicate the version of condor running on a machine

via it's ClassAd.


Consider this my feature request to have these attributes defined

automagically on the startd.


- Ian


Attachment: classad_shared.h
Description: classad_shared.h

Attachment: shared.C
Description: shared.C