iLCDirac + FCC

P. Apausa, A. H. Ebrahimnejadkalahroudi, B. Francois, M. Hernandez Villanueva,
P. Kontaxakis, D. Lange, A. Sailer, J. Smieško, B. Wach

FZU, Prague

15 October 2026

iLCDirac in a nutshell

DIRAC extension for the linear collider community and FCC
- Dedicated job types/applications, VO configuration, metadata conventions
Multi-VO instance: ILC, CALICE, FCC
Services hosted at CERN
- Ten Puppet-managed RHEL 9 VMs, services run under runit
- Web portals: ilcdirac.cern.ch, fccdirac.cern.ch

In production: iLCDirac v35.0.12 (Sep 2026) on DIRAC v8
Systems used: CS, DMS, FS, RMS, SMS, TS (multi-VO), WMS, Monitoring/Accounting, Workflow, RSS (passive), WebApp
- Not used: Production System
Extension features
- Overlay system for beam-background files
- Pandora particle-flow calibration service
- Transformation plug-ins
- AutoSingularityComputingElement: picks the container image from the job's software

Authentication: VOMS-Admin → CERN-provided IAM for all three VOs: ilc-auth, calice-auth, fcc-auth

∼49 CPU-years from Jun 2025 to Oct 2026, all VOs
- DESY-HH 24, CERN 23, the rest < 1 each
- Mostly the ILC campaign for the ILD detector, Mar–May 2026
- Peak of ∼790 cores in use

Resources registered in the configuration

VO	Compute sites	CEs	Queues	SEs
ILC	42	119	169	24
CALICE	9	22	29	6
FCC	3	22	37	5

Central MC productions driven by the Transformation System
- MCGen → Simulation → Reconstruction, or MCGen → Delphes
- Software: Key4hep stack, distributed via CVMFS
- Output: EDM4hep files registered in the DIRAC File Catalog
- Replacing the homegrown EventProducer (HTCondor + EOS)
Users can also submit their own jobs, e.g. FCCAnalyses on the grid
- fccanalysis submit grid via iLCDirac: FCCAnalyses PR #538 (open)
Autumn campaign: first serious production campaign, planned for the end of October 2026
- Runs on the DIRAC v8 production servers
Scope so far: cover the current FCC needs — not building the computing system for the future experiments

Resources registered in iLCDirac
- Computing: CERN; BARI and CNAF to be tested
- Storage: CERN (EOS disk, CTA tape), BARI, CNAF, GLASGOW
Usage so far (test productions)
- ∼66 TB at CERN, after a few clean-ups of test productions
- So far only CERN computing used
Rucio is also tested at FCC — currently separate from DIRAC, so every SE has to be registered in both systems
- More resources already registered in Rucio
- Used to replicate the Winter2023 campaign across several sites
- DIRAC–Rucio connection to be set up

Effort to bring iLCDirac to DIRAC v9 and DiracX
Two steps
1. Fresh DIRAC v9 server, configuration copied over
2. Gradual migration to DiracX — one subsystem at a time
Format: weekly mini hackathons with a shared running doc

Date	Milestone
17 Jun	Kick-off: status of iLCDirac and how to evolve it
12 Aug	Onboarding to the iLCDirac infrastructure
18 Aug	iLCDirac 36.0.0a1 (DIRAC v9) client
25 Aug	Helm values, CS conversion, legacy exchange key
8 Sep	Helm deployment, RSS installed
15 Sep	OpenSearch, DiracXAuthDB, web interface
22 Sep	CS synchronisation, admin IdP
6 Oct	WMS services, agents and executors on the v9 server

            Many thanks to Andre Sailer for the guidance and
            support
          

Production stays on iLCDirac v35 (DIRAC v8) for now
- Latest release v35.0.12 (18 Sep 2026)
- The FCC autumn campaign runs on v8
- Switch to v9 once the autumn-campaign dataset requests die down, likely Q1/Q2 2027
iLCDirac v36 (36.0.0a1): first release for DIRAC v9
- Following the DIRAC 9.0 migration notes
- New v9 server set up from scratch, configuration copied over: voilcdirac901
RSS (passive) in iLCDirac — v9 needs the full installation
- Added ResourceStatusDB and ResourceManagementDB, plus all agents from the old configuration
WMS on the v9 server: services, agents (e.g. PilotStatusAgent) and optimizer executors
- Latest aim: be ready to start adding computing and storage resources

Helm charts deployed on CERN PaaS (OpenShift), project ilcdiracx-prod
Web interface: ilcdiracx-prod.app.cern.ch
Release naming: colourful animals, alphabetically
- Current release: mosquito
For now: as many services as possible provided by CERN IT
- S3 (OpenStack), MySQL (DBOD), OpenSearch, IdPs (fcc-auth, CERN SSO)
- Redis as a pod in the deployment

Following the DiracX installation guide
Legacy exchange key generated, new DiracXAuthDB created
DIRAC CS converted to DiracX YAML, stored in config_store_prod
DIRAC → DiracX config synchronisation working
- Run by hand for now, cron job next
So far only the FCC VO is configured
- Identity provider set up for the diracxAdmin and fcc_user groups
- Both can log in to the DiracX web interface

Documentation was good enough to get a deployment running in a few hackathon sessions
Secrets in the Helm values.yaml: configuration and credentials in one file, so it cannot be kept in git as is
Upgrades: some secrets are generated just once and not cleared on a new release
- e.g. the Redis host secret had to be updated by hand
RSS becoming mandatory: iLCDirac ran RSS (passive), v9 needs the full installation
Hosted OpenSearch: permissions and port had to be sorted out

Get the v9 server and DiracX to the point where computing and storage resources can be added
- On the way: end-to-end job test — get the grid proxy, submit, track, retrieve output
Run the CS synchronisation periodically (cron job)
Set up S3 storage in the OpenStack “ILC Dirac” project
CI and testing: no staging or local development setup yet
- Idea: iLCDirac CI on the master branch against the v9 server and ilcdiracx
- Tests using the FCC VO, logging into ilcdiracx from CI
Add the ILC and CALICE VOs
- New clients, user synchronisation
Add the remaining groups (fcc_prod, …)
Set up the DIRAC–Rucio connection
In parallel: autumn campaign on DIRAC v8; production switch to v9 in Q1/Q2 2027

iLCDirac serves the ILC, CALICE and FCC VOs; FCC is its fastest-growing user
FCC is moving its central productions to the iLCDirac Transformation System
- Autumn campaign at the end of October — the first serious one
The aim so far is to cover the current FCC needs, not to build the system for the future experiments
DiracX@FCC: iLCDirac on DIRAC v9 and a first DiracX deployment on CERN PaaS, with the configuration synchronised from DIRAC
Next: adding computing and storage resources; production on v9 in Q1/Q2 2027

            Thanks to the DIRAC/DiracX developers for the
            documentation and support
          