INFN-GRID Globus evaluation

(WP 1)

Massimo SgaravattoINFN Padova

for the INFN Globus groupglobus@infn.it

http://www.infn.it/globus

Globus Some basic services (security, information service, resource

management, …) must be implemented in order to implement and use a Grid for real applications

Globus identified as possible Grid framework providing these services

… but it has been developed mainly for “traditional” computing, different from computing in HEP

High performance vs. high throughput Supercomputers vs PC farms Distributed data intensive computing not addressed

Need to assess what can be used for HEP environment WP1 “Installation and Evaluation of the Globus Toolkit” of the

INFN-GRID Project Goal: evaluation of the Globus toolkit

Which services can be useful ? What is necessary to integrate/modify ? What is missing ?

Globus ArchitectureApplications

Core ServicesMetacomputing

Directory Service

GRAMGlobus

Security Interface

Heartbeat Monitor

Nexus

Gloperf

Local ServicesLSF

Condor MPI

NQEEasy

TCP

SolarisIrixAIX

UDP

High-level Services and ToolsDUROC globusrunMPI Nimrod/GMPI-IO CC++

GlobusView Testbed Status

GASS

Proposed work plan Security

To access GRID resources mechanisms for user authentication and authorization needed

Evaluation of GSI service

Information Service To discover the GRID resources (CPU, storage, network, …)

mechanisms to “publish” them must be defined Analysis of GIS service to “publish” information using a uniform and

standard interface

Resource Management Necessary a uniform interface to submit jobs on GRID resources

Uniform standard interface to different resource management systems Uniform standard language for task management Assessment of Globus services for resource allocation and process

management

Proposed work plan Data Access and Migration

High performance and reliable tools needed to “manage” data (access to remote data, data transfers, wide area replica, …)

Assessment of Globus tools for data management (GASS, Globusftp)

Fault Monitoring Faults in a GRID environment must be promptly detected and

recovery mechanisms must be implemented Evaluation of HBM service for fault detection

Execution Environment Management Code migration (moving the application where the job will

actually be executed) as a possible implementation strategy Evaluation of GEM service to support code migration

Globus installation tools Reduce complexity and manpower for Globus installation and

maintenance

Globus installation tools Flavia’s presentation

INFN-GRID installation tool to shorten the installation time of the Globus toolkit, avoid common mistakes, support for specific customisations

Possibility (option) to install optional software, to proceed with INFN specific customizations (INFN CA, configuration of a hierarchical GIS architecture), to install and use specific INFN tools

Proven to be successful within INFN (used to setup a INFN GRID testbed) and also outside (CERN, FNAL, …)

Security Evaluation of Globus GSI

User authentication (implementation based on X.509 certificates)

User authorization “managed” by grid-mapfile (mapping between Grid users and local users)

Some shortcomings, but the GSI security model seems to satisfy our requirements

Some shortcomings already addressed INFN-CA used to sign certificates CRL (issued by INFN CA) distribution Centralized management of grid-mapfiles

Security Centralized management of the grid-mapfiles

Goal: Ease the sharing of the same access policies (represented by the grid-mapfiles) for groups of hosts with common purposes

Proposed system Central repository (LDAP server) to store user

certificates and to define groups of users Certificates published by CA manager Group manager responsible for editing group

memberships (using a LDAP client) Resource owners (Globus administrators) periodically

(i.e. cron job) “connect” to this repository, “download” the subject of the certificates that meet a specified criterion (i.e. all users of group X), and produce grid-mapfile entries

Security AFS tests

Analysis of what can be done now with the existing tools (quite unfit for any real need)

Possible ways to address the existing shortcomings identified

New Globus tool (gsiklog) available

Information Service Alessandro’s presentation

Evaluation of Globus GIS (Grid Information Service) Definition and implementation of a hierarchical

architecture of GIS 1.1.3 Performance and scalability tests Web interface for browsing Various shortcomings must be addressed (to use the

GIS in a production environment) Mixed push/pull model more suitable than a pull model Performance Lack of security …

Dc=bo, Dc=infn,dc=it,o=grid

Bologna

GIIS

INFN CMS GIIS

GIIS

Dc=pd,Dc=infn,dc=it,o=grid

Exp=cms, o=grid

Top Level INFN GIIS

Dc=infn,dc=it,o=grid

Padova

INFN GIS Topology

GRIS

Resource Management Most of these activities as collaboration with Grid

Workload Management work package

Evaluation of Globus resource management architecture Evaluation of Globus GRAM

Tests with fork, Condor, LSF and PBS as underlying resource management systems

The model is fine, but lack of “robustness” (needed for real production environments)

Memory leaks in the Globus job manager (fixed) Scalability (one job manager for each job) Reliability (the job manager is not persistent) …

Globus resource management architecture (simplified design)

GlobusGRAM

CONDOR

GlobusGRAM

LSF

GlobusGRAM

PBS

Site1Site2 Site3

Broker Grid InformationService (GIS)

Submit jobs

ResourceDiscovery

Information on characteristics andstatus of local resources

LocalResource

ManagementSystems

Globus GRAMas uniform interface

to different local resource management systems

Broker chooses in whichresources to submit the jobs

(not implemented in the Globus framework)

Farms

RSL

RSL

RSL

Resource Management Evaluation of GRAM API Evaluation of GRAM Reporter (“cooperation” between GRAM and

GIS) in particular for farms Many useless attributes (at least for our needs), attributes not

calculated (always defined as 0), some attributes not properly calculated by Globus shell scripts

Some important information describing the farms and the submitted jobs (necessary for example for a resource broker) missing

Draft proposal for a possible modification of the default schema Evaluation of RSL as uniform language to specify resources

More flexibility required Submission of Condor jobs to Globus resources

Condor-G (useful as a reliable crash-proof job submission service) GlideIn

Evaluation of MPICH-G2 vs. MPICH Some shortcomings found (lack of support for shared memory, worse

latency performance wrt. MPICH)

Data management Tests with GASS

Service to ease the access to remote files without having a distributed file system and/or transferring files from/to remote storage systems

Tests with command line tools and APIs Problems (huge decrease in transfer rate) when transferring

big files Tests with Globusftp alpha release 2

Collaboration with WP network INFN-GRID Tests of new features

Support for GSI mechanisms Capability of resuming interrupted file transfers Throughput tests using parallel data transfers

Antonio’s presentation

Other services Fault Monitoring (HBM)

Evaluation of HBM for fault detection (for “system” and “user” processes)

… but the HBM package is not seeing active development

Execution Environment Management (GEM) Evaluation of GEM as service for code migration … but the GEM service now provides only

limited capabilities (executable staging)

WP 1: Deliverables & Milestones Deliverables

Tools, documentation and operational procedures for Globus deployment (6 Months)

Final report on suitability of the Globus toolkit as basic Grid infrastructure (6 Months)

Milestones Basic deployment Grid infrastructure for the

INFN GRID (6 months) Globus installed on ~ 40 machines on ~ 10 different

sites

Conclusions The activities of WP 1 are over The Globus toolkit can provide basic

services useful to create and deploy usable Grids, but many shortcomings and issues must be addressed

… more details in the report

Other info: http://www.infn.it/globus