[AG-TECH] Vanishing Bridges

Thu Oct 14 06:09:12 CDT 2010

On 14/10/2010, at 7:12 AM, Christoph Willing wrote:

>
> On 14/10/2010, at 2:13 AM, Thomas Uram wrote:
>
>> Last week I set up a test registry, registered a bridge with it,  
>> and successively queried bridges from the registry all day with no  
>> trouble. Granted, these were all local, but if the problem appears  
>> as reliably as I've heard, I would have expected to see a problem  
>> even in this case. We clearly need to narrow down the cause of the  
>> problem some more. What details do we have about the failure cases?
>
>
> We have very few details, unfortunately. I recall, nearly a year  
> ago, I was able to replicate the problem and at that time I thought  
> it may have something to do with newer python versions (since 2.6  
> was implicated in another problem I'd seen and the replicable cases  
> were on newer systems which included python2.6).
>
> However when I was retesting a Debian lenny system (which uses  
> python2.5) just night before last, I also ran a test with the new  
> Ubuntu maverick (with python2.6). Both ran fine overnight i.e.  
> maverick seems OK despite using python2.6 (however note that other  
> tests in France were not successful with maverick, so ....). Anyway,  
> since maverick had run OK for me, I then started a test with Ubuntu  
> lucid (also python2.6), one of the systems with which I'd previously  
> been able to replicate the problem. This time it has run overnight  
> without any bridge disappearances - I just tried a bridge cache  
> purge from home and it showed up fine (still showing up as  
> "LucidTest" in the bridge list
> if the www.ap-accessgrid.org registry is enabled).

On re-reading this last line, I wondered if the problem has something  
to do with the registry itself. I guess all the failure instances so  
far have been using the default ANL registryUrl at www.accessgrid.org/registry/peers.txt 
, whereas my tests the last few days, which produced no failures, all  
used the APAG registryUrl at www.ap-accessgrid.org/registry/peers.txt.  
Obviously each points to a different registry so could that be the  
problem?

I spent all day today testing different _recent_ distros (Slackware  
13.1, Ubuntu lucid & maverick) against the different registries. In  
all cases, bridges running against the ANL registry disappeared within  
10-15 minutes. In all cases except one (not repeatable), bridges  
running against the APAG registry did not disappear.

My theory therefore is that ANL registry is running with an older  
version of the AG toolkit that is not compatible with VenueClients  
running newer AG versions. Tom's recent testing with a separate test  
registry supports this theory (assuming the test registry is running a  
recent version of AG toolkit). Philippe's comment that tests with  
maverick were unsuccessful also supports the theory (assuming those  
tests used the default ANL registry).

Philippe and Tom (and anyone else interested),

Could you try running (using the current AG release) a bridge against  
the APAG registry - some command like:
   Bridge3.py --name=Testing123 --location=wherever --registryUrl=http://www.ap-accessgrid.org/registry/peers.txt

Leave it running for about an hour or two to confirm it does not  
disappear. Then stop it and run it again, this time against the ANL  
registry with something like:
    Bridge3.py --name=TestingXYZ --location=wherever --registryUrl=http://www.accessgrid.org/registry/peers.txt

Look for failure in the first 15 minutes.

If the fault is in the ANL registry, why do so many bridges _not_  
disappear? Looking at the list of bridges, the names are becoming very  
familiar i.e. they've been around a long time. I'm guessing that these  
bridges are running on older versions of the AG toolkit - still  
compatible with whatever version is running on the ANL registry machine.

Of course, if the test results are in line with the theory, it still  
doesn't explain the underlying cause. A quick look through bridge &  
registry related AG code doesn't reveal any recent changes so the real  
cause may actually be down in some of the supporting software (python,  
m2crypto anyone?) which are constantly updated in each new Linux  
release (typically every 6 months). If so, this issue will eventually  
also bite Windows & Mac users as new OS versions introduce up to date  
versions of python, m2crypto etc. for them too.

chris

> So we know very little about failure cases;
>  - there are many in France
>  - I was previously able to replicate but not now
>  - I _think_ I recall that Todd Z reported that he had seen the  
> problem too
>
> chris
>
>
>> On Oct 13, 2010, at 2:27 AM, Philippe d'Anfray wrote:
>>
>>> Bonjour,
>>>
>>> I was not there yesterday and it's probably too late to "purge the  
>>> cache" (there's just a Lucid test by now)
>>>
>>> By the time we decided to switch to debian because we have a  
>>> seminar that will be transmitted
>>> tomorrow and really need the bridge to work (in fact to be visible  
>>> to new users and there it is).
>>>
>>> If it works also with "maverick" it is a good news for other users  
>>> in France (but in the first test we made the
>>> bridge disappears too...)
>>>
>>> Merci pour tout!!
>>>
>>>
>>> Philippe d'Anfray
>>>
>>>
>>>
>>>
>>> Le 12/10/2010 12:56, Christoph Willing a écrit :
>>>>
>>>>>>
>>>>>> We're still stuck with this bridge problem, we tried with  
>>>>>> Ubuntu 10.10 this afternoon but it is still the same. If you  
>>>>>> can confirm us that it works fine with Debian, I'll reconfigure  
>>>>>> our server and install a Debian.
>>>>>
>>>>>
>>>>> I'm just about to leave for a short holiday so I can't reconfirm  
>>>>> that Debian still works correctly until late next week.
>>>>
>>>> I'm now running a test bridge with Debian "lenny". It has been  
>>>> running nearly 5 hours without any problem so far. I'm also  
>>>> running another test bridge using the new Ubuntu "maverick",  
>>>> which and been running for over 4.5 hours - also no problem yet.  
>>>> I will let them both run overnight here (your day time) and you  
>>>> can check whether they're still running OK if you purge your  
>>>> bridge cache (assuming you have www.ap-accessgrid.org as one of  
>>>> your bridge registries) and look for the bridges named DebTest  
>>>> (Debian lenny 64bit) and MaverickTest (Ubuntu maverick 32bit).
>>>>
>>> <Philippe_d-Anfray.vcf>
>>
>
> Christoph Willing                       +61 7 3365 8316
> QCIF Access Grid Manager
> University of Queensland
>

Christoph Willing                       +61 7 3365 8316
QCIF Access Grid Manager
University of Queensland