AliEn v2-17: Before the data taking

Patricia Méndez Lorenzo, CERN IT/GS-EISALICE Offline Meeting (2-Sep-2009)

Alice Offline Meeting 2

Outlook During this summer a new AliEn v2-17

has been released At this moment it is in production and

distributed across all ALICE sites ALICE is entering in data taking mode

and this will be the AliEn version in useThis talk will present this new version

and the requirements we have for the sites before data taking

2/09/09

Alice Offline Meeting 3

Generalities of the AliEn v2-17

Available in central services at the end of July 2009

Final distribution in all sites by middle August The new version has the following (general)

features: Large number of improvements with many

contributions More weight to central services and reduction on

the list of services running in the (local) VOBOXES New requirements in terms of services for all

ALICE sites

2/09/09

Alice Offline Meeting 4

AliEn v2-17: New features New gcc4.1.2 available

Distribution of a single gsoap (previously the AliEn distribution contained 2)

3rd party tranfers for file distribution with Xrd3cp (excluding T0-T1 transfers)

In terms of xrootd there are new improvements

Reinforcement of the CREAM-CE module and full split of gLite-WMS and CREAM-CE submission modes

2/09/09

Alice Offline Meeting 5

AliEn v2-17: New features (cont.) More options to save files from the jobs

New job status: DONE_WARNING Torrent improvements New and simplified transfer model Catalogue structure improved Deletion of orphan files Deprecate SE and FTD on the sites

SE defined in LDAP but not as a local service running at the VOXES

Usual Bug fixesLet’s explain some of these features in detail

2/09/09

Alice Offline Meeting 6

Job Output Once the job is finished, the user will

not need to specify the output SE anymore

Default behaviour: Output of the job will be stored in two

working SE close to the job (via the JA) Users can specify (via jdl) how many

copies they want to have

2/09/09

Alice Offline Meeting 7

Job Output: Schema

2/09/09

JobsTaskQueue Job

Broker

Job Manager

CE

Central servicesSite services

Non AliEn Services

SplittingExpired

Priorities Merging

Zombies

File catalogue

LFN GUIDMetadata

PackmanMonALISA

CE

CMPackmanMonALISA

CMSite A

Site B

JobManager Job

Broker

Job optimizers

JA

xrootd

xrootd

Alice Offline Meeting 8

New job Status: DONE_WARNING

2/09/09

The Job output could not be copied to none of the SEs

SAVED_WARNING

DONE_WARNING

Output copied to SEs but below the number of required copies

Output registered inthe catalogue but below the number of required copies

Alice Offline Meeting 9

New transfer model No changes from the user perspective FTD is not running in the VOBOX anymore

It was previously one of the local services running in the VOBOX

Only one FTD per type of transfers (FTS or xrd3cp)

Transfer status: INSERTED WAITING ASSIGNED

TRANSFERRING DONE

2/09/09

Alice Offline Meeting 10

Transfer model: Schema

2/09/09

TransfersTransferQueue Job

Broker

Job Manager

CE

Central servicesSite services

Non AliEn Services

SplittingExpired

Priorities Merging

Zombies

File catalogueLFN GUIDMeta

data

FTD

PackmanMonALISA

CE

CMPackmanMonALISA

CMSite A

Site BTransfer Manager Transfer

Broker

Transfer optimizers

fts

bbftp

xrdcp

SRM

SRM

xrootd

Alice Offline Meeting 11

Orphan Files Up to now removal of LFN from the

catalogue did not mean removal of the file from the SE Removal feature implemented now

Deletion is asynchronous Using the transfer model and FTD with

another deamon responsible of the removal

2/09/09

Alice Offline Meeting 12

Improvements in Torrent Torrent is the new software installation

procedure chosen by ALICE The sw area usage has shown many

problems in the past For each job the required sw will be

installed in the working area of the job In the case the torrent client (aria2c)

to download new packages cannot be used, wget will make this job instead

2/09/09

Alice Offline Meeting 13

Torrent Philosophy JA lands on a virgin worker node From a centralized machine a small script is

sent: Finds a scratch area in a local disk Installs latest version of AliEn

Simple requirements: wget Starts a Job Agent

JobAgent will install required experiment software After finishing, removes everything

Or leaves it for the next agent... (still to be evaluated)

2/09/09

Alice Offline Meeting 14

Torrent Schema

2/09/09

Tracker

Seeder

Download& seed Download

& seed

Download& seed

Download& seed

Download& seed

Download& seed

alitorrent.cern.ch

Site A

Site B

Alice Offline Meeting 15

WLCG submission modules Submission to CREAM-CE and LCG-CE (via gLite-WMS)

are now separated The query to the info system has now changed

LCG-CE from the information system CREAM-CE from the CREAM-DB

This is however a problem although not a show-stopper The code has bugs preventing a good publication through this model We are back to the information system as the source also for the

CREAM-CE Multi-cluster sites are now usable for ALICE

CE ranking has been defined LDAP configuration has been improved

Less conditions needed (implemented in the code)

2/09/09

Alice Offline Meeting 16

AliEn v2-17: Deployment at the sites Once the v2-17 version was deployed at all

sites the submission to WLCG sites began to fail Both in WMS and CREAM submission modes

The problem was related only to the LDAP configuration for those sites The new v2-17 version requires changes in some

field of the CE configuration of LDAP This has been already done to all sites

The sites are nos well configured and no major issues are now reported

2/09/09

Alice Offline Meeting 17

Requirements for the sites The new AliEnv2-17 version comes together with

some important requirements for the sites Deployment of SL5 in all WNs and VOBOXEs

(T0,T1,T2 sites) DEADLINE: Mid-September 2009

Deployment of a CREAM-CE at all sites (T0,T1,T2 sites)

DEADLINE: Mid-November 2009 The main problem that we continue to face is

unresponsiveness of sites to upgrade. This is an important issue that we must resolve as a collaboration

2/09/09

Alice Offline Meeting 18

Status of the CREAM-CE Planned as replacement of the current

LCG-CE Submission procedures allowed by

CREAM-CE Submission to CREAM-CE via the gLite-WMS Direct submission via generic clients

Since Nov 2008 the WLCG encourages sites to provide a CREAM-CE in

paralel mode to the LCG-CE

2/09/09

Alice Offline Meeting 19

The WLCG Milestones on regards with CREAM-CE

https://twiki.cern.ch/twiki/pub/LCG/MilestonesPlans/WLCG_High_Level_Milestones_20090623.pdf

2/09/09

1) NOT ACHIEVED2) ACHIEVED ✔3) Today 23 sites are publishing CREAM in the prod-BDII. ~39 still missing

Alice Offline Meeting 20

Implementation and Experiences in ALICE

ALICE has been the 1st LHC experiment testing CREAM-CE and providing the developers with a continuous feedback The experience has been very positive ALICE requires the deployment of the CREAM-CE service at all sites

which provide support to the experiment The testing began in Summer 2008 and since Feb 2009 the

CREAM-CE submission is part of the AliEn standard distribution

However as of today, 13 sites FOR ALICE are providing CREAM-CE CERN, KISTI, INFN-Torino, CNAF, RAL, FZK, Kolkata, IHEP, SARA,

Subatech, Legnaro, SPbSU, Prague THE SAME NUMBER OF SITES FOR ALICE PRESENTED

DURING CHEP09! NO ADVANCES!!

2/09/09

Alice Offline Meeting 21

ALICE results with CREAM-CE

CREAM is part of the AliEn distribution since Feb 2009

2.8M jobs done since Feb08 using CREAM-CE resources

2/09/09

Alice Offline Meeting 22

SL(C)5 testing Almost parallel to the CREAM-CE

testing, ALICE has been successfully testing SL5 resources in two sites: CERN (behind CREAM-CE) RAL

ALICE has largely verified that the experiment is ready to run on these resources

2/09/09

Alice Offline Meeting 23

WLCG-MB conclusions (Summarized by I. Bird) the final

conclusions regarding the SL5 migration of the WLCG-MB at the 4th of August: Now is the time to push to complete the SL5

migration at all sites, including the Tier 2s The experiments are all ready and able to

use SL5 resources Tier 1s and Tier 2s should plan this

migration as rapidly as possible, so that the majority of resources will be migrated asap

2/09/09

Alice Offline Meeting 24

ALICE conclusions for SL(C)5 ALICE has agreed during the last 13/08/09 TF meeting to

collaborate actively with their sites to ensure the timely migration

The experiment has asked for the SL5 distribution in all official forums: WLCG-GDB, WLCG-MB and workshops

Following the strategy explained for the CREAM-CE ALICE cannot maintain an hybrid SL4/SL5 setups at the sites

SL4 is deprecated and ALICE will not maintain it anymore

The DEADLINE established by the experiment is mid-September 2009

SL5 VOBOX Max priority for WLCG-GD ALICE counts on one preliminary version by today

2/09/09

Alice Offline Meeting 25

Summary AliEn v2-17

With plenty new improvements Simplified transfer mechanism

Less AliEn services on the site The new version enforces the central services features and light the local

VOBOXES In addition: WLCG features

CREAM-CE The experiment is asking for the deployment of CREAM-CE at all sites since Summer

2008 The double support we are currently providing (WMS/LCG-CE and CREAM-CE) cannot

scale during real data taking After more than 1 year asking for this service, ALICE will deprecate the use of the

WMS/LCG-CE in benefit of the CREAM-CE by mid-November 2009 SLC5

Following the strategy explained for the CREAM-CE ALICE cannot maintain an hybrid SL4/SL5 setups at the sites

SL4 is deprecated and ALICE will not maintain it anymore The DEADLINE established by the experiment is mid-September 2009

2/09/09