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David Cameron
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Message 39621 - Posted: 16 Aug 2019, 10:21:15 UTC

Hi all,

ATLAS is progressively moving away from the SLC6 operating system based on RHEL6 to CentOS 7 which is based on RHEL7. Since almost all CERN or ATLAS-specific software is now taken from CVMFS there is no need for a "Scientific Linux CERN" version of the operating system and all of our grid sites will provide vanilla CentOS 7. All the ATLAS tasks here currently run on SLC6 provided through VirtualBox or Singularity containers so we need to update to CentOS 7.

So what does this mean for you?

For VirtualBox tasks:

We will soon update the image to CentOS 7. In theory this just means a new application version with a new vdi file so you don't need to do anything and shouldn't notice any difference in the tasks.

For native tasks:

We will stop sending tasks to SLC6 machines. If you are running SLC6 then you will need to upgrade or run virtualbox tasks. Hosts which are not SLC6 will not be affected, but we will change the image used by Singularity to CentOS 7. Again, in this case there is no need for you to do anything unless you are running SLC6.

The timeline for these changes is probably in the next month or two, we will of course do extensive testing on the dev project before changing anything here, so please head over there if you would like to help out.

One other improvement for those of you running native tasks is that we will remove the need to install singularity, since ATLAS now provides its own version in CVMFS. We're currently testing this on the dev project and it looks like it works well, so we will roll that out here soon (sooner than the switch to CentOS 7).
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Jim1348

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Message 39623 - Posted: 16 Aug 2019, 11:37:43 UTC - in response to Message 39621.  

One other improvement for those of you running native tasks is that we will remove the need to install singularity, since ATLAS now provides its own version in CVMFS. We're currently testing this on the dev project and it looks like it works well, so we will roll that out here soon (sooner than the switch to CentOS 7).

This is extraordinarily well-explained. Thanks.
But what about Theory Native? Will it need singularity?
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Message 39624 - Posted: 16 Aug 2019, 11:45:27 UTC - in response to Message 39623.  

But what about Theory Native? Will it need singularity?

Yes, it will, but it doesn't require a preinstalled singularity any more.
Instead it will use a version taken form the CVMFS repository.

David Cameron wrote:
One other improvement for those of you running native tasks is that we will remove the need to install singularity, since ATLAS now provides its own version in CVMFS.
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David Cameron
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Message 39625 - Posted: 16 Aug 2019, 15:02:36 UTC - in response to Message 39623.  

One other improvement for those of you running native tasks is that we will remove the need to install singularity, since ATLAS now provides its own version in CVMFS. We're currently testing this on the dev project and it looks like it works well, so we will roll that out here soon (sooner than the switch to CentOS 7).

This is extraordinarily well-explained. Thanks.
But what about Theory Native? Will it need singularity?


No, Theory native uses runc which is a different container tool. You can find some more explanation in Laurence's message on the theory boards

However removing ATLAS' need for volunteers to install Singularity brings the requirements for ATLAS and Theory native nicely into line, i.e. you only need CVMFS to run both.
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Message 39626 - Posted: 16 Aug 2019, 15:33:03 UTC - in response to Message 39625.  

No, Theory native uses runc...

Ah, right.
Sorry. Mixed it up.
May have been unconcentrated.
:-(
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David Cameron
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Message 39982 - Posted: 20 Sep 2019, 13:55:33 UTC

We plan to stop sending native WU to SLC6 hosts on Monday 23rd. I have checked the database for active SLC6 hosts and there were around 40 in total. However not all of these run ATLAS and some of them run ATLAS vbox, so only a handful of hosts should be affected.
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maeax

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Message 40004 - Posted: 23 Sep 2019, 6:26:07 UTC - in response to Message 39982.  
Last modified: 23 Sep 2019, 6:42:36 UTC

The two SL610 (Linux 2.6.32-754.22.1.el6.x86_64) have finished the last work.
What's about SL76 (Linux 3.10.0-1062.1.1.el7.x86_64)?
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David Cameron
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Message 40006 - Posted: 23 Sep 2019, 7:37:15 UTC - in response to Message 40004.  

The two SL610 (Linux 2.6.32-754.22.1.el6.x86_64) have finished the last work.
What's about SL76 (Linux 3.10.0-1062.1.1.el7.x86_64)?


This one is ok. Only Linux 2.x will be affected.
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Henry Nebrensky

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Message 40019 - Posted: 25 Sep 2019, 10:18:14 UTC - in response to Message 39982.  

We plan to stop sending native WU to SLC6 hosts on Monday 23rd. I have checked the database for active SLC6 hosts and there were around 40 in total...

Thanks for the warning - unfortunately I had to retire my SL6 box in a hurry as the new "owners" of the space it was hiding in wanted it cleared :( .
Not sure what will happen to the others - at this rate I may yet have time to try out CentOS 8 ...
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David Cameron
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Message 40020 - Posted: 25 Sep 2019, 13:34:15 UTC - in response to Message 39982.  

We plan to stop sending native WU to SLC6 hosts on Monday 23rd. I have checked the database for active SLC6 hosts and there were around 40 in total. However not all of these run ATLAS and some of them run ATLAS vbox, so only a handful of hosts should be affected.


This change was just implemented (a bit later than expected). Let us know of any problems.

We added this to the configuration:
<min_os_version>30000</min_os_version> 
to exclude kernel versions less than 3 (SLC6 is 2.6.32).
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Message 40026 - Posted: 26 Sep 2019, 7:06:46 UTC - in response to Message 40020.  

We plan to stop sending native WU to SLC6 hosts on Monday 23rd. I have checked the database for active SLC6 hosts and there were around 40 in total. However not all of these run ATLAS and some of them run ATLAS vbox, so only a handful of hosts should be affected.


This change was just implemented (a bit later than expected). Let us know of any problems.

We added this to the configuration:
<min_os_version>30000</min_os_version> 
to exclude kernel versions less than 3 (SLC6 is 2.6.32).


This setting didn't work as expected and many hosts were unable to download native WU, so it has been rolled back. It seems like it only works if the operating system of your host matches "Linux x.yz...". If you have something like "Linux CentOS CentOS Linux release 7.6.1810 (Core) [3.10.0-957.21.3.el7.x86_64|libc 2.17 (GNU libc)]" then it doesn't work.

I will now try a different approach, by enforcing singularity is present on all hosts, thus SLC6 hosts can still crunch if they install singularity. I'll release a new native version soon.
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Message boards : ATLAS application : Upcoming changes


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