1. LCG experience in Integrating Grid Toolkits
Zdenek Sekera
IT Division , CERN
16/11/2018
CHEP2003

2. zdenek.sekera@cern.ch CHEP2003
Outline
What is LCG?
LCG project goals
With whom we work ?
Basic LCG milestones
What is LCG-0 ?
What are the plans for LCG-1 ?
What is the process to get to LCG-1 ?
Conclusions
Authors: Piera Bettini, Ian Bird, Flavia Donno, Maarten Litmaath,
Di Qing, Louis Poncet, Andrea Sciaba, Zdenek Sekera,
Marco Serra, David Smith
16/11/2018
CHEP2003

3. zdenek.sekera@cern.ch CHEP2003
What is LCG?
LCG = LHC Computing Grid
Creating the infrastructure for computing needs of LHC HEP experiments
(Atlas, CMS, Alice, LHCb)
All are worldwide collaborations, consequently the software has to work worldwide
16/11/2018
CHEP2003

4. zdenek.sekera@cern.ch CHEP2003
Project Goals
Goal – Prepare and deploy the LHC computing environment to help the experiments to analyze the data coming from the detectors
applications - tools, frameworks, environment, persistency
computing system  global grid service
cluster  automated fabric
collaborating computer centres  grid
CERN-centric analysis  global analysis environment
central role of data challenges
This is not another grid technology project – it is a grid deployment project
16/11/2018
CHEP2003

5. zdenek.sekera@cern.ch CHEP2003
LCG goals
LCG goal is to bring physics world together by creating a user friendly, production quality environment for data processing and physics analysis.
How? By integrating different grid toolkits or grid middleware into a homogenous package to guarantee the interoperability among different “ways of doing things”.
LCG does NOT write grid middleware.
We want physicist to use the same commands no matter where they work, in the USA, Europe, Asia.
This makes them feel “at home” and surely their efficiency is much higher.
16/11/2018
CHEP2003

6. What is “production quality”?
It is all of the following in no particular order:
availability 24 x 7
performance
stability, robustness
user friendliness
maintainability
user support
16/11/2018
CHEP2003

7. zdenek.sekera@cern.ch CHEP2003
Who are our partners?
LCG is currently a “customer” of:
iVDGL - VDT toolkit (including Globus & Condor toolkits)
EDG - European DataGrid project
EDT - European DataTag project (monitoring)
Globus - underlying software
GLUE schema – HICB (DataTag & iVDGL) product
HICB = HEP Intergrid Coordination Board
LCG can be considered a joint effort of all.
It pulls together needed components from existing projects.
We have to give credit to all developers in all these organizations for their effort in helping us to achieve the final LCG goal: to provide a well-defined user friendly environment.
16/11/2018
CHEP2003

8. zdenek.sekera@cern.ch CHEP2003
Basic LCG milestones
LCG is focused on batch & experiments data challenges (phase 1)
LCG release milestones:
February - LCG-0 (deployment test, not publicly available)
July - LCG-1 (production pilot)
First publicly available LCG service
November - LCG-1 (production system)
Performance release needed for data challenges
in 2004.
We have a first set of integrated software and currently use it for deployment tests (LCG-0)
16/11/2018
CHEP2003

9. zdenek.sekera@cern.ch CHEP2003
LCG-0
WorldGrid demo last year (e.g Supercomputing 2002) demonstrated interoperability between VDT-EDG toolkits
We went a step further by integrating VDT and EDG into a single package consisting of
EDG VDT “Glue” schema
It’s purpose is to setup infrastructure and release process rather than Grid functionality itself
The important task is to determine the necessary work to be done by laboratories to get integrated
16/11/2018
CHEP2003

10. zdenek.sekera@cern.ch CHEP2003
LCG-0 deployment
We are deploying it on tier 1 centers, goal is about 10 sites in the initial deployment
Currently deployed by:
CERN, RAL, CNAF, Taiwan
being installed by:
FNAL, U of Tokyo
we expect a few more sites later
16/11/2018
CHEP2003

11. What did we learn with LCG-0
Release process is difficult:
Many specific issues for different sites (how many service machines, what services on service machines, security issues)
Packaging is an issue (USA x Europe, rpm x tar, pacman x LCFG)
Installation is complicated, we cannot force ourselves on sites with our installation tools when they have already their own
Configuration is major problem, it is far too complex
Testing is a huge issue, we need to test different architectures, features, networking, interoperability
16/11/2018
CHEP2003

12. zdenek.sekera@cern.ch CHEP2003
Research? Deployment?
If we want to/need to reconfigure service nodes, all neccessary changes are now propagated to configuration files manually. That cannot stay this way, we have to find much more automatic ways.
Compare to Linux installation 3-4 years ago and today.
We must probably go the same way of understanding what the real configuration issues are, only we would like to be much faster.
The integration of worker nodes must be resolved by sites themselves, we will help.
These issues (and more) make the difference between the research project ending with a demo and the product to be used for a production.
16/11/2018
CHEP2003

13. zdenek.sekera@cern.ch CHEP2003
What will be LCG-1?
Expected to be:
EDG VDT (Globus 2.2.4)
We are just beginning LCG-1.
We have a Certification & Testing testbed at CERN consisting of 40 machines we can configure as desired.
Certification & Testing is a joint project (e.g. VDT is testing Globus and Condor).
16/11/2018
CHEP2003

14. LCG-1 Certification Testbed
U of Wisconsin
40 machines at CERN
16/11/2018
CHEP2003

15. zdenek.sekera@cern.ch CHEP2003
LCG-1 certification
basic grid functionality
connectivity
grid services
security
resource brokering
data management
(replication, catalog)
configurability
error recovery
real world applications
site verification suite
16/11/2018
CHEP2003

16. Test and Validation process
Developers
machines
Build
system
Development
Testbed ~15cpu
Certification
Testbed ~40cpu
Production
Unit Test
Build
Integration
Certification
Production
WPs add unit
tested code to
CVS repository
Run nightly
build
& auto. tests
Individual WP
tests
Grid certification
Certified public
release
for use by apps.
Build system
Integration
Team
Test Group
Users
Tagged package
WPs
Tagged release selected for certification
Overall
release
tests
Certified release selected for deployment
Application Certification
Fix problems
Appl. Representatives
Releases
candidate
Releases
candidate
Tagged
Releases
Certified
Releases
Office hours
24x7
Bugzilla anomalies reports
16/11/2018
CHEP2003

17. zdenek.sekera@cern.ch CHEP2003
Conclusions
With LCG-0 we have proved it is possible to integrate different toolkits (VDT & EDG) into a single package that can be repeatable deployed.
We have learned the difficult issues (installation, configuration, testing) that will require a special attention for LCG-1.
The process how to get the first (July) LCG-1 release out has been setup and is operational.
Incremental releases will be required to correct problems according to their priorities up to November LCG-1 release and possibly beyond.
There is a difficult and long road ahead towards LCG-1 due to the complex software and aggressive schedule but we believe it can be managed with a systematic determined approach.
It is a highly collaborative project so everybody has to contribute.
16/11/2018
CHEP2003