Obtaining and Renewing a CERN Grid Certificate in LHCb

Photo by Marián Hubinský, licensed under CC BY-SA 4.0, via Wikimedia Commons.

Working with LHCb resources requires a valid grid certificate. Here’s a step-by-step guide for obtaining and renewing your certificate, tailored for lxplus and LHCb DIRAC access.

Obtaining a Certificate

Instructions: Official LHCb Certificate Guide

• Use Firefox — Chrome and other browsers may not work well for certificate management.
• Import all required certificates into Firefox (as described in the link above).
• Import your personal certificate into Firefox. You’ll be prompted to set an import password — remember it!
• Transfer the certificate to your lxplus account with scp:

scp MyCertificate.p12 username@lxplus.cern.ch:~

• SSH into lxplus:

ssh -Y <username>@lxplus.cern.ch

• Convert the certificate to PEM format (you’ll be asked to set a PEM passphrase — use a different one than the import password):

lb-dirac dirac-cert-convert MyCertificate.p12

• Join the LHCb Virtual Organisation (VO) via the VOMS registration page. You may need to wait ~24 hours for validation.
• Once validated, initialize your proxy on lxplus:

lhcb-proxy-init

Enter your PEM passphrase when prompted.

✅ You now have access to the LHCb DIRAC portal.

Renewing a Certificate

1. Download your renewed certificate from the CERN Certification Authority.

• Transfer it to lxplus:

scp NewCertificate.p12 <username>@lxplus.cern.ch:

• In Firefox, delete the old certificate and import the new .p12 one.
• Update your IAM profile:
• Visit IAM Profile
• Under X.509 certificates, unlink the old certificate.
• Then, link the new certificate you just imported.
• On lxplus, clear your previous credentials:

rm -rf ~/.globus

• Convert the new certificate to PEM as before:

lb-dirac dirac-cert-convert NewCertificate.p12

• Test your setup: Follow this checklist to ensure everything is working.
• Optionally run:

lhcb-dirac

• Finally, reinitialize your proxy:

lhcb-proxy-init

✅ You have renewed your certificate.

Originally published at https://fotisgiasemis.com on February 5, 2023.