Joining the Grid

Andrew McNab

28 March 2006 Andrew McNab – Joining the Grid

Outline

● LCG – the grid you're joining

● Related projects● Getting a certificate–Care of your certificate

● Joining a Virtual Organisation–AUP

28 March 2006 Andrew McNab – Joining the Grid

LCG

• The LHC Computing Grid (LCG)– http://www.cern.ch/LCG/– The worldwide computing infrastructure for

LHC– Led by CERN–Majority of resources are at the other sites

• Has more than 100 fully operational sites, in 31 countries– About 190 are operational at some level– Sites from US to Japan, but mostly in Europe

28 March 2006 Andrew McNab – Joining the Grid

LCG: World

28 March 2006 Andrew McNab – Joining the Grid

LCG: Europe

28 March 2006 Andrew McNab – Joining the Grid

LCG: by region

28 March 2006 Andrew McNab – Joining the Grid

LCG: by region

28 March 2006 Andrew McNab – Joining the Grid

Related projects

• EGEE is also led by CERN– Develops software to be adopted by LCG– EU-funded, and intended to get non-HEP on board

• GridPP is the PPARC-funded UK HEP grid project– Runs LCG in the UK– Contributes effort to EGEE

• The National Grid Service (NGS): non-HEP UK grid– Increasingly adopting ideas/software from LCG

• Open Science Grid (OSG): the US DoE/NSF grid– Increasingly interoperates with LCG

28 March 2006 Andrew McNab – Joining the Grid

Getting a cert

• All authentication on LCG is done by X.509 digital certificates– these contain a unique name for each user– “/C=UK/O=eScience/OU=Manchester/L=HEP/CN=andrew

mcnab”

• To use LCG you need to get a certificate• This requires proving who you are with photo ID• For the UK Certification Authority, you start this

via their website– https://ca.grid-support.ac.uk/

28 March 2006 Andrew McNab – Joining the Grid

Requesting the cert

28 March 2006 Andrew McNab – Joining the Grid

Certificate process

• Apply for the certificate on the CA website– Choose the right Registration Authority (RA)– “Manchester HEP” in our case

• Go to the RA operator (Sabah in our case) and provide your photo ID

• You receive an email from the CA when your certificate is ready (a day or so – the signing machine is offline)

• You can then load it into your web browser from the CA website

28 March 2006 Andrew McNab – Joining the Grid

Care of your cert

● Applying for the certificate has created a secret Private Key (a huge number) and a Public Key (another huge number) which the CA has turned into a certificate

● These are inside your web browser at the end of the process

● Any body with access to your web browser or the Private Key can pretend to be you – so treat it like a password

● There are instructions on the CA website for getting your certificate and private key out the browser, and into the file used by the Grid command line tools

28 March 2006 Andrew McNab – Joining the Grid

Virtual Organisations

● Your certificate proves who you are, but doesn't give you access to any sites

● To get that, you need to join a Virtual Organisation (VO), like ATLAS or BaBar

● Use the “User Registration” link from http://www.cern.ch/LCG/ and follow the instructions

● Different VOs have slightly different procedures– it always involves associating your certificate

with your request to join– then a manager of the VO decides if you really

are a bona fide member of that collaboration

28 March 2006 Andrew McNab – Joining the Grid

AUP

● Joining a VO requires accepting the LCG Acceptable Usage Policy

● This is a common AUP accepted by all LCG sites– Avoids the need to fax off 190 different Computer

Centre forms when you join● The AUP is very short – less than a page – and pretty innocuous– basically: “Don't abuse the sites” and “You're

legally responsible for what you do.”– In return, you get access to a huge amount of

CPU, with local accounts created for you on demand