[Engine-devel] [Design for 3.2 RFE] Improving proxy selection algorithm for Power Management operations

[Yair Zaslavsky]

----- Original Message -----
> From: "Eli Mesika" <emesika at redhat.com>
> To: "Dan Kenigsberg" <danken at redhat.com>
> Cc: "engine-devel" <engine-devel at ovirt.org>
> Sent: Sunday, November 11, 2012 1:18:53 PM
> Subject: Re: [Engine-devel] [Design for 3.2 RFE] Improving proxy selection algorithm for Power Management operations
> 
> 
> 
> ----- Original Message -----
> > From: "Eli Mesika" <emesika at redhat.com>
> > To: "Itamar Heim" <iheim at redhat.com>
> > Cc: "engine-devel" <engine-devel at ovirt.org>
> > Sent: Friday, November 9, 2012 12:06:05 PM
> > Subject: Re: [Engine-devel] [Design for 3.2 RFE] Improving proxy
> > selection algorithm for Power Management operations
> > 
> > 
> > 
> > ----- Original Message -----
> > > From: "Itamar Heim" <iheim at redhat.com>
> > > To: "Eli Mesika" <emesika at redhat.com>
> > > Cc: "engine-devel" <engine-devel at ovirt.org>, "Michael Pasternak"
> > > <mpastern at redhat.com>, "Simon Grinberg"
> > > <sgrinber at redhat.com>, "Dan Kenigsberg" <danken at redhat.com>
> > > Sent: Friday, November 9, 2012 12:02:37 PM
> > > Subject: Re: [Engine-devel] [Design for 3.2 RFE] Improving proxy
> > > selection algorithm for Power Management operations
> > > 
> > > On 11/09/2012 10:52 AM, Eli Mesika wrote:
> > > 
> > > >> >
> > > >> >  > FenceWrapper
> > > >> >
> > > >> >i understand danken suggested going this way, rather than
> > > >> >than
> > > >> >another
> > > >> >instance of vdsm.
> > > >> >is vdsm only calling these scripts today and all logic is in
> > > >> >engine,
> > > >> >or
> > > >> >does vdsm has any logic in wrapping these scripts (not a
> > > >> >blocker
> > > >> >to
> > > >> >doing FenceWrapper, just worth extracting that logic from
> > > >> >vdsm
> > > >> >to
> > > >> >such a
> > > >> >script, then using it in both. i hope answer is 'no
> > > >> >logic'...)
> > > > vdsm has some logic that maps between the call passed to it
> > > > from
> > > > engine and the actual parameters generated for the script.
> > > > AFAIK, this logic only "builds" the correct arguments for the
> > > > command according to the agent type
> > > >
> > > 
> > > can we extract it to an external wrapper?
> > > I'd hate to fix bugs/changes twice for this.
> > 
> > I'll check it with danken on SUN
> 
> Well, looked at it a bit , the VDSM code is in fenceNote function in
> API.py
> What I think is that we can exclude the fenceNote implementation to a
> separate fence.py file and call it from the API.py
> Then we can use one of the following in Java to call the method from
> fence.py
> 1) jython
> 2) org.python.util.PythonInterpreter
> 
> See http://stackoverflow.com/questions/8898765/calling-python-in-java
> 
> danken, what do you think ?

Hi,
JDK 6 (and above) has a ScriptEngine.
I would suggest using this JSR.

For example, look at - http://www.alittlemadness.com/2008/07/15/java-6-using-python-via-the-new-scripting-engine/

What kinda bothers me is the fact that both your link, the link I provided use Jython, and not Python - i.e the script itself has to run over the jvm.
We should see if the JVM allows us to run the fencing script (no JVM restrictions).
It's kinda surprising to me - I was sure that ScriptEngine can run Python (i.e - on the linux machine itself) and not Jython.
I will continue checking.

> 
> > 
> > > 
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