On 06/12/2018 12:53, Ian Collier - UKRI STFC wrote:
> Hi Alessandra
>
>> On 6 Dec 2018, at 10:04, Alessandra Forti <[log in to unmask]> wrote:
>>
>> Hi Gareth,
>>
>> I'm certainly not talking at cross purposes. I explicitely said on two occasions CVMFS is not good for unstable and in development software and for small groups who don't have a software team behind.
> And it that second part I am questioning - it is far too sweeping. That really was all I was picking up
>
> But then you came back with further spurious objections.
maybe they have a tiny directory in that tarball that doesn't need much
configuration or doesn't change much and they had to install it once. So
we are back to my point 1.
spurious? Really?
cheers
alessandra
> There are small teams happily using CVMFS, this is simply true. I cited two services I am aware of that make that easier - although I am sure they could be made even easier to use.
>
> And there are groups choosing to /package/ their software as both tarballs and as containers, (that was your second objection) who are then /distributing/ it via CVMFS, and gaining from the efficiency and performance that cvmfs offers.
> I did not - at any stage - suggest it is the only solution.
>
> And yes, if software is extremely unstable then that is a situation where you might choose other approaches - but then that is relatively unlikely to be run at large scale across many distributed resources.
>
> —Ian
>
>
>
>> Either here we talk about small groups for whom the grid is this mythical beast or we are not. CVMFS is part of it. New groups reject it because they don't have enough large scale or stable software. It's as simple as that. LSST eventually used the gridpp CVMFS area but that was because the DC2 software was stable enough and didn't need updates. Before that it was tarballs on the storage.
>>
>> We accepted tarballs for 15 years with all their drawbacks without questioning. Containers are fundamentally fancy tarballs integrated in user spaces and cgroups which allow a user to run consistently independently from the environment. Nobody is going to run docker on the WNs though it will become rootless too and that opens new possibilities. But for the time being we will run singularity on the WNs reading images from and/or dumped in CVMFS from docker.
>>
>> cheers
>> alessandra
>>
>> On 06/12/2018 09:50, Gareth Roy wrote:
>>> Hi,
>>>
>>> I think you may both be talking a little bit at cross purposes... I think Alessandra may be focusing on development and early pathfinding exercises while Ian is looking at mature production runs (this may be putting words in your mouth).
>>>
>>> In going back to the main direction Alastair was taking this and thinking about it in terms of the email Dave sent and particularly point 5, I think new users will have a journey for any sort of large scale that looks like:
>>>
>>> Development -> Testing -> Staging -> Production
>>>
>>> The technologies at each level may be different and require different access or highlight different needs... which we should be cognizant of when onboarding new experiments. Each technology has its strengths and weakness... containers for instance work great at all levels in the above cycle but have drawbacks (singularity is _not_ the same as docker, from a deployment, operation or security standpoint). Running arbitrary container user payloads is fraught with risk without really understanding the security model. CVMFS is excellent at efficiently deploying software to a wide (geographical) range of resources, it's fairly easily understood from a user perspective (just a filesystem) but is slow to respond to rapid changes, can have problems with caching etc.
>>>
>>> Now I know you both know this, but I think where we sometimes run into problems with new user communities is they don't. We need to present the technology with both its strengths and weaknesses to allow them to make a judgement based on their (not our needs)... I think the phrase I'm looking for is informed consent.
>>>
>>> Just my thoughts and maybe input for Friday's meeting which I can't make as I'm at a Data Centre meeting at Glasgow.
>>>
>>> Thanks,
>>>
>>> Gareth
>>>
>>>
>>>
>>>
>>>
>>>
>>> On 06/12/2018, 09:15, "Testbed Support for GridPP member institutes on behalf of Alessandra Forti" <[log in to unmask] on behalf of [log in to unmask]> wrote:
>>>
>>> On 06/12/2018 08:54, Ian Collier - UKRI STFC wrote:
>>> >
>>> >> On 5 Dec 2018, at 15:21, Alessandra Forti <[log in to unmask]> wrote:
>>> >>
>>> >> On 05/12/2018 15:11, Ian Collier - UKRI STFC wrote:
>>> >>>
>>> >>>> On 5 Dec 2018, at 14:15, Alessandra Forti <[log in to unmask]> wrote:
>>> >>>>
>>> >>>> PS CVMFS is not good for small scale groups or groups that don't have an established code. We should discuss containers.
>>> >>> I think that is rather sweeping.
>>> >> experience. Again with LSST and SKA. Former went for tarballs on the storage, and latter went for containers. Other smaller groups have similar probles and prefer to upload tarballs. Even I who am one of the early fans of CVMFS wouldn't go for it if I was developing.
>>> > Again, tarballs are very easy to unpack onto cvmfs.
>>> sure they are you have to develop, connect to a machine unpack the
>>> tarball and wait for it to be propagated. It then requires a number of
>>> setup scripts for the job to access. It cannot be streamlined and it
>>> requires time. Not a good solution for unstable software.
>>> >
>>> >>> I know of more than one solution for making cvmfs easiy to use for small teams (here at RAL and also at Nikhef). There are surely more. And once you have your software on cvmfs it has many large advantages.
>>> >>>
>>> >>> This is not to say that containers don’t have their place. (Of course they work /really/ well unpacked and distributed via cvmfs.)
>>> >> I'm afraid this is debatable. Unpacked are 3-5 times larger and you need the space for that. With CERN we are setting up a common repository for the LHC experimets but it will need policies on images lifetimes, and the registries again offer a directness CVMFS doesn't and which during development is necessary.
>>> > But most of the space is de-duplicated so shared between images, and it will be a rare job that actually access every file in a container.
>>> that's why we are setting up a common repository at CERN with the CVMFS
>>> devs specifically working on getting the images from docker, but as I
>>> said different workflows might still need the registries.
>>> cheers
>>> alessandra
>>> >
>>> > —Ian
>>> >
>>> >
>>> >> cheers
>>> >> alessandra
>>> >>> —Ian
>>> >>>
>>> >>>
>>> >>>
>>> >>>> On 05/12/2018 14:11, Alessandra Forti wrote:
>>> >>>>> Hi Alastair,
>>> >>>>>
>>> >>>>> On 05/12/2018 13:07, Alastair Dewhurst wrote:
>>> >>>>>> Hi All
>>> >>>>>>
>>> >>>>>> Sorry for the late reminder but I was waiting for Dave B email (To Grid or not to Grid?) to be sent round.
>>> >>>>>>
>>> >>>>>> We will have another technical meeting on Friday 7th December on “Onboarding new communities”. This will be in two parts:
>>> >>>>>> 1) I will start with a description of the plans for the Tier-1 to provide direct batch system access for (some) new communities. The intention is that this would introduce them to some of the aspects of the Grid (e.g. CVMFS) but still keep it easily accessible. If the requirements of the VO grow then we would move them towards using the GridPP DIRAC instance. The Tier-1 is obviously not the only site that can onboard new communities and often the site that the VO contact is based is the best place to introduce people to the Grid. We should therefore try and align the services we offer. I would appreciate feedback on my plans for the Tier-1, I want people to feel that this will benefit all GridPP sites.
>>> >>>>>>
>>> >>>>> this is how we did it with LSST. First direct access and then Dirac, then file catalogue. I cannot say they appreciated it considering they are showing around a "post-mortem" which is one of the reason you are now sending this email.
>>> >>>>>
>>> >>>>> cheers
>>> >>>>> alessandra
>>> >>>>>
>>> >>>>>> 2) We should have a discussion about how best to describe the problems people will face if they need to use distributed resources. We should also discuss how best to describe the various software and services we have used to solve them.
>>> >>>>>>
>>> >>>>>> If anyone would like to send me suggested input in advance, I will try and incorporate this into the agenda.
>>> >>>>>>
>>> >>>>>> Agenda can be found here:
>>> >>>>>> https://indico.cern.ch/event/779045/
>>> >>>>>>
>>> >>>>>> Alastair
>>> >>>>>>
>>> >>>>>> To unsubscribe from the TB-SUPPORT list, click the following link:
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>>> >>>>>>
>>> >>>>> --
>>> >>>>> Respect is a rational process. \\//
>>> >>>>> For Ur-Fascism, disagreement is treason. (U. Eco)
>>> >>>>>
>>> >>>>>
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>>> >>>>
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>> --
>> Respect is a rational process. \\//
>> For Ur-Fascism, disagreement is treason. (U. Eco)
>>
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