Re: [Vampire-public] Comments about recent news & some ideas about the future

[Nicolas Burrus]

On Tue, Feb 24, 2004 at 01:43:37PM +0100, Akim Demaille wrote:
> >>> "Akim" == Akim Demaille <address@hidden> writes:
> 
>  >> So what's the point? We would like to share the host informations
>  >> for Olena and Transformers.
> 
>  > Actually, it seems to me that another critical feature would be to
>  > have Vampire probe the machines to set up this configuration file.  I
>  > don't trust users for this.
> 
> It would be most valuable to capitalize over the experience of the
> Condor group, who faced the very same issue.  They have found a
> solution, which is probably satisfying.  Making something different
> would have to be justified.
> 
> Please, read
> 
>     http://www.cs.wisc.edu/condor/manual/v6.6/4_1Condor_s_ClassAd.html
> 
>     4.1 Condor's ClassAd Mechanism
> 
>     ClassAds are a flexible mechanism for representing the
>     characteristics and constraints of machines and jobs in the Condor
>     system. ClassAds are used extensively in the Condor system to
>     represent jobs, resources, submitters and other Condor daemons. An
>     understanding of this mechanism is required to harness the full
>     flexibility of the Condor system.

I think we can steal a lot of ideas from their system. But we must
keep in mind some fundamental differences between Condor and Vampire:

* Condor has a client of every hosts. Each client describes itself
  with a class-ad.
* Vampire centralize host information. We should provide a way to
  regroup hosts in the configuration file, since most of them may have
  similar parameters.

* Condor doesn't care about software configuration, etc. Only binaries
  are launched on remote hosts, so that the hardware and OS information is 
  generally enough to decide whether a particular machine can be used or not.
* Vampire needs complex software configuration information, depending
  on the packages to be tested. Selecting machines only relying on
  hardware configuration is not enough.

* Condor is usually used to get the results given by a program on
  several set of parameters. For one particular set of parameter,
  condor do not mind on which machine it will be run, as long as the machine
  satisfies the requirements and can compute the results.
* Vampire will usually check the same parameters on several hosts.

Actually I think that ClassAd is well-suited to describe the host
configurations (the hosts.xml of current vampire), but we still need
to add some factorizing features.

However, the techniques used by condor to choose a machine for a
particular program is by far too limited in my sense for the purpose of
Vampire.

Finally, there are some good ideas in ClassAd we could get, but I'm
not sure that actually implementing ClassAd would help.

But I haven't been deeply into the details of Condor ClassAds, I might
underestimate its possibilities!