Hi Antonio,
In our case, we already have moved all our services to UMD-3. We did not
find any relevant issue during the migration, the only things to comment
is about the APEL service that use a different schema now so it is
necessary to upgrade the CreamCE and the APEL services to UMD-3 at the
same time and also to comment about the VOMS service because YAIM is not
kept on this service and there is to run the configuration manually.
First, we moved services like the UI, Top-BDII, site-BDII, My-Proxy,
VOMS, DPM, WMS, LFC to UMD-3, so we had a mix of services running UMD-2
and UMD-3 at the same time for some days.
Then, we continued the migration to UMD-3 with the CE service, we moved
first the WNs to UMD-3, so for one time we had WNS in UMD-3 and UMD-2
running at the same time. Finally, we moved the Cream-CE and the
APEL-service to UMD-3. I think it should not have any issue for running
UMD-2 and UMD-3 services at the same time while the batch system version
is the same on Cream and on the WNs.
Cheers,
Esteban
On 12/02/14 11:30, Antonio Delgado Peris wrote:
> Hi,
>
> Thanks Peter.
>
> Mixing EMI-2 and EMI-3 WNs is an interesting use case for us, because
> it avoids a complete downtime of the site for the upgrade, though we
> will certainly schedule one if it is required.
>
> However, since we do not support MPI jobs at CIEMAT, let me ask for
> more information regarding your comment: are there any other specific
> problems related to the mix of WN from different versions, or just
> MPI? Well, even if you tell me that there are no precise issues but
> that the configuration was not tested or is in general suspected to
> cause problems, we will consider it enough to avoid risking it :-)
>
> Cheers,
> Antonio
>
>
>> Dear Antonio,
>>
>> EGI UMD verifiers tested, although not extensively, a mixed
>> configuration with CREAM and WN from different EMI versions.
>> CREAM EMI-3 and WN EMI-2 are compatible. And also the other way around.
>>
>> What is not advisable is to have some WN from EMI-2 and other from
>> EMI-3 in the same subcluster, because some applications such as MPI do
>> not work properly with different WN versions together.
>>
>> Regards
>> Peter
>>
>>
>> On 11 February 2014 18:47, Antonio Delgado Peris
>> <[log in to unmask]> wrote:
>>> Dear all,
>>>
>>> We have recently received a message regarding the UMD-2/EMI-2
>>> decommissioning calendar, notifying us about the need to start
>>> planning the
>>> upgrade to EMI/UMD-3 services.
>>>
>>> Thinking about a possible gradual upgrade, I would like to ask about
>>> compatibility issues when mixing EMI/UMD-2 and EMI/UMD-3 services, in
>>> particular in what regards WNs, glexec, CREAMs, Argus and BDII.
>>> E.g.: can we
>>> mix different WNs from both releases and different CREAMs from both
>>> also?
>>>
>>> Given that I've found no warning against this, my first idea is that
>>> all
>>> combinations should be possible (except for the case of APEL**), but
>>> I would
>>> like to be sure.
>>>
>>> ** Warned here:
>>> https://wiki.egi.eu/wiki/UMD-3:UMD-3.0.0#emi.apel.sl6.x86_64
>>>
>>> Thanks a lot for any comments!
>>>
>>> Cheers,
>>>
>>> Antonio
>>
>>
--
++-------------------------++
Esteban Freire García
Centro de supercomputación de Galicia
Avda. de Vigo s/n. Campus Vida
15705 - Santiago de Compostela. Spain
Tlfn.: 981 56 98 10 Extension:274
Fax: 981 59 46 16
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