Generic policy rules and
principles
Jean-Yves Nief
Talk overview

An introduction to CC-IN2P3 activity.
 iRODS in production:
– Why are we using it ?
– Who is using it ?
– Prospects.

iRODS rules policies through examples:
– Resource Monitoring System.
– Biomedical applications:
• Human data.
• Animal data.
–
–
–
–
Arts and Humanities.
Other rules: Mass storage system interface, access rights.
Pitfalls.
Future usages.
Repository workshop - Garching
20/09/10
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CC-IN2P3 activities

Federate computing needs of the french scientific community in:
– Nuclear and particle physics.
– Astrophysics and astroparticles.
 Computing services to international collaborations:
- CERN (LHC), Fermilab, SLAC, ….
 Opened now to biology, Arts & Humanities.
dapnia
Repository workshop - Garching
20/09/10
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iRODS @ CC-IN2P3: why using it ?

National and international collaborations.
 Users spread geographically (Europe, America, Australia…).
 Need for storage virtualization:
- federation of heterogeneous storage (disks, tapes) and data
access system (MSS, databases…).
- transparent data access for end users.
- middleware working on heterogeneous OS.
- common logical name space.
- virtual organization (access rights, groups etc…).
- metadata search.
- Easy interface with any kind of clients applications (APIs,
drivers).
Repository workshop - Garching
20/09/10
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iRODS @ CC-IN2P3: why using it ?

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SRB being used since 2003:
– 3 PBs handled for 10 different experiments (HEP, astro,
biology).
– Decomissionning: end of 2012 ?
Limitation:
– no centralized data management (DM).
 no enforcement of DM policy.
iRODS rules based policy:
– adequate solution.
– from the user point of view: virtualization of data
management policy.
Repository workshop - Garching
20/09/10
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iRODS @ CC-IN2P3: who is using it ?

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Arts and Humanities (Adonis):
– Long term data preservation.
– Web and batch jobs access.
Biology (phylogenetic), fluid mechanics:
– grid jobs.
Biomedical applications:
– Human and animal imagery.
Biology (phylogenetic), fluid mechanics:
– grid jobs.
High Energy physics:
– Neutrino experiment.
Repository workshop - Garching
20/09/10
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iRODS @ CC-IN2P3: who is going to use it ?

Astrophysics experiments:
– LSST …
Other biomedical, physics projects.
 iRODS will be part of French NGI.
 All the SRB instances to be moved to
iRODS.
 1 PB should be reached soon.

Repository workshop - Garching
20/09/10
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Rules examples: Arts and Humanities

Ex: archival and data publication of audio files
(CRDO).
CRDO
CC-IN2P3
CINES
Archive
Repository workshop - Garching
Fedora
1. Data transfer: CRDO 
CINES (Montpellier).
2. Archived at CINES.
3. iRODS transfer to CCIN2P3: iput file.tar
4. Automatic untar at Lyon
+ checksum.
5. Automatic registration in
Fedora-commons
(delayed rule).
20/09/10
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Rules examples: biomedical data

Human and animal data (fMRI, PET, MEG etc…).
 Usually in DICOM format.
 Main issue for human data:
– Need to be anonymized !
 Need to do metadata search on DICOM files.
 Rule:
1. Check for anonymization of the file: send a warning if not true.
2. Extract a subset of metadata (based on a list stored in iRODS)
from DICOM files.
3. Add these metadata as user defined metadata in iRODS.
Repository workshop - Garching
20/09/10
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Rules examples: resource monitoring
system
Perf script
iRODS data server
1.
Ask each server for its
metrics: rule engine cron
task (msi).
2.
Performance script
launched on each server.
3.
Results sent back to the
iCAT.
4.
Store metrics into iCAT.
5.
Compute a «quality factor»
for each server stored in an
other table: r.e. cron task
(msi).
Perf script
DB
iRODS data server
iRODS iCAT server
Perf script
iRODS data server
Perf script
iRODS data server
Repository workshop - Garching
20/09/10
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Other rules
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Mass Storage System integration:
– Using compound resources: iRODS disk cache + tapes.
– Data on disk cache replication into MSS asynchronously (1h later)
using a delayExec rule.
– Recovery mechanism: retries until success, delay between each
retries is doubled at each round.
ACL management:
– Rules needed for fine granularity access rights management.
– Eg:
• 3 groups of users (admins, experts, users).
• ACLs on /<zone-name>/*/rawdata => admins : r/w, experts + users : r
• ACLs on all others subcollections => admins + experts : r/w, users : r
Repository workshop - Garching
20/09/10
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Developpements needed

Scripts/binaries:
– Metadata extraction from DICOM files.
– Registration of files into Fedora-Commons.
– …
 Needed whatever storage system being used underneath.
 Micro-services:
– ACLs, tar/untar of archives file,…
 APIs already available, did not require a large amount of work (parts of
iRODS distro).
– Resource Monitoring System: bigger developpement, includes
modification of the iCAT schema.
 Rules:
– Most of them are simple.
– Somes requires more work (Adonis project), workflow more complex.
Repository workshop - Garching
20/09/10
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Pitfalls and bugs
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Writing complex rules:
– Avoid writing them directly using the .irb syntax.
– Becomes difficult to debug especially with nested actions.
solution: need to use ruleGen to generate rules in a more user
friendly manner.
Some memory leaks found with irodsReServer with Oracle as a
backend:
 Fixed in 2.4.
delayExec syntax bugs:
Fixed in 2.4 and 2.4.1.
Rules in configuration file at the moment:
– Must be consistent on all the iRODS servers.
 Will be in the iCAT database in the future.
Repository workshop - Garching
20/09/10
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Prospects

Rules for database interaction (in progress):
– Will be used by DTM (developped at CC-IN2P3):
• DTM managed list of tasks to be processed by a batch cluster.
• DTM requires a database to manage the tasks.
– Rule launched by the client will interact with the DTM database through
iRODS:
• More security: iRODS used as a proxy server (database behind a
firewall, use iRODS authentication.
• Database schema upgrade transparent for the client (no SQL code
launched on the client side).
 Xmessaging system (part of iRODS):
– Allow to exchange messages between different iRODS process or clients.
– e.g.: Could be used to monitor job status in a distributed computing
environnement.
Repository workshop - Garching
20/09/10
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Acknowledgement

Thanks to:
– Pascal Calvat.
– Yonny Cardenas.
– Thomas Kachelhoffer.
– Pierre-Yves Jallud.
iRODS at CC-IN2P3
03/25/10
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