NGI CZ:CVMFS for auger

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CVMFS for VO auger


Historical introduction (can be skipped by impatient readers)

CVMFS is a distribution tool for software (and other relatively small files). It started to be used by LHC experiments, several other projects deployed it later, all with very good experience. LHC projects use master repository called stratum-0 based at CERN. The master repository for some other projects is hosted by RAL and is decribed at GRIDPP wiki page. VO auger is not supported by RAL site and we started a CVMFS repository hosted by OSG. RAL site can replicate the master repository and distribute it via the same stratum-1's as for other nonLHC VOs. However the path would change from /cvmfs/oasis.opensciencegrid.org/auger to /cvmfs/auger.gridpp.ac.uk and the non-relocatable auger offline software would not work.

Status - March 2015 - all major sites supporting VO auger are correctly configured and setup verified by test jobs.


Setup for the VO auger

A new solution was discussed during EGI Communnity Forum 2014 at Helsinki and shortly after it adopted. A new stratum-0 with a base name egi.eu is hosted by RAL. VO auger software manager (currently not defined by the VOMS role, but by explicitly given list of DNs) can upload software to upload server cvmfs-upload01.gridpp.rl.ac.uk. It is accessible via gsissh.We must upload files to /home/augersgm/cvmfs_repo (link to /cvmfs-mirror/auger.egi.eu) and unpack them (if we used a tarball). An example:

gsiscp -P 1975 /tmp/jiri/CORSIKA-74000_Fluka.2011.2b.6.tgz cvmfs-upload01.gridpp.rl.ac.uk:/cvmfs-mirror/auger.egi.eu/
gsissh -p 1975 cvmfs-upload01.gridpp.rl.ac.uk 
cd /cvmfs-mirror/auger.egi.eu
tar xzf CORSIKA-74000_Fluka.2011.2b.6.tgz
rm CORSIKA-74000_Fluka.2011.2b.6.tgz

Then a cronjob copies the content to the stratum-0. We should wait at most 3 hours. Clients see the software in the path /cvmfs/auger.egi.eu/.


Client installation

Many sites have installed clients on their worker nodes. It is also installed on the shared User Interfaces ui1.grid.cesnet.cz and ui2.grid.cesnet.cz. The installation procedure is described on the CERN CVMFS page, where you can also download required packages. Adrian Sevcenko (Adrian.Sevcenco@spacescience.ro) prepared a script for the VO auger for easier client installation.


Clients setup

I suppose that client is installed on WNs (probably on request from some LHC VO). If it is not the case and you want to install cvmfs client for example on your machine, follow instructions from the official CVMFS manual. The configuration for egi.eu domain is in 2 files: /etc/cvmfs/domain.d/egi.eu.conf and /etc/cvmfs/keys/egi.eu.pub. Their content is:

cat /etc/cvmfs/domain.d/egi.eu.conf
CVMFS_PUBLIC_KEY=/etc/cvmfs/keys/egi.eu.pub
CVMFS_SERVER_URL="http://cvmfs-egi.gridpp.rl.ac.uk:8000/cvmfs/@org@.egi.eu"
cat /etc/cvmfs/keys/egi.eu.pub

-----BEGIN PUBLIC KEY----- MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAxKhc7s1HmmPWH4Cq1U3K 4FNFKcMQgZxUrgQEfvgkF97OZ8I8wzC9MWqmegX6tqlPmAzYWTM+Xi4nEBWYRhd+ hVN/prHyYGzb/kTyCSHa9EQtIk9SUyoPfQxkGRnx68pD5con8KJySNa8neplsXx+ 2gypwjasBRQLzB3BrrGhrzZ5fL84+dsxNBBW6QfNO1BS5ATeWl3g1J27f0GoGtRO YbPhaAd9D+B+qVo9pt3jKXvjTZQG0pE16xaX1elciFT9OhtZGaErDJyURskD7g3/ NotcpBL5K5v95zA/kh5u+TRrmeTxHyDOpyrGrkqRaT5p+/C1z0HDyKFQbptegCbn GwIDAQAB -----END PUBLIC KEY-----


Squid setup

To avoid overloading of Stratum-1 servers and improve performance, you should define a local cache. It is defined in /etc/cvmfs/default.local file. An example:

CVMFS_REPOSITORIES=auger.egi.eu
CVMFS_HTTP_PROXY="http://squid.farm.particle.cz:3128
CVMFS_CACHE_BASE=/var/lib/cvmfs
CVMFS_QUOTA_LIMIT=10000

Additional parameters CVMFS_CACHE_BASE and CVMFS_QUOTA_LIMIT define location and size of the cache on the target machine, not on the squid server.


If you do not have local proxy server, you can try direct access (probably only as a test before you setup a local cache:

CVMFS_HTTP_PROXY=DIRECT


Software compilation

I compile the software directly an a worker node. This would immediately show missing packages. I assume that all WNs (at leaste on our sites) are installed identically and if it compiles and runs on one node, it should run on every node. However the  partition  /cvmfs/auger.egi.eu/ is mounted as read only. The solution is to do (on an offline WN):

mount -o bind /tmpfs/auger /cvmfs/auger.egi.eu/

We tried also --make-private option, but it is supported only by newset kernels.


Links

CVMFS documentation at CERN
OSG CVMFS documentation


Acknowledgement

We thank to the EGI CVMFS task force and RAL for their support. Catalin Condurache was the key person for CVMFS support for nonLHC VOs.


--Chudoba 22:40, 11 July 2014 (CEST)