report on the infn-grid globus evaluation massimo sgaravatto infn padova for the infn globus group...
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Report on the INFN-GRID Globus evaluation
Massimo SgaravattoINFN Padova
for the INFN Globus [email protected]
Why Globus ? Some basic services (security, information
services, resource management, …) must be deployed in order to implement and use a Grid for real applications
Globus identified as possible Grid framework providing these services
WP “Installation and Evaluation of the Globus Toolkit” of the INFN-GRID Project
Evaluation of the Globus toolkit (effectiveness, completeness, robustness, ease of use, …)
Provide feedback to the Globus team Bringing attention to existing problems and requirements Providing fixes to some problems
Globus activities within INFN Activities driven by the following work plan
Evaluation of Globus security services Evaluation of Grid Information Service Evaluation of Globus services for resource management Evaluation of Globus tools for data management Evaluation of Globus HBM for fault monitoring Evaluation of Globus GEM for execution environment
management Globus deployment and installation tools
Not only a simple evaluation Some existing shortcomings addressed Specific configurations and customizations implemented
INFN-GRID Globus evaluation activities performed between June 2000 and January 2001
“Official” Globus 1.1.3 (1.1.4 for MPICH-G2) release tested
Globus security services The Globus GSI security model seems to satisfy the INFN
community current requirements on security One time login mechanism Use of X509 certificates Possibility for extending relations of trust to multiple CA’s without
having to interfere with their X.500 naming scheme Some shortcomings
Need for limited (by scope or purpose) proxies Globus team is already addressing this problem
Memory leaks in the GAA library Fixed: patches provided by INFN
Cryptic diagnostics Now partially solved with newer code
Interface between GSI and AFS Already addressed with gsiklog
No tools for group management Addressed with new CAS service
INFN customizations on security INFN-CA CRL distribution Centralized management of the grid-mapfile
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
(subjects) 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 (e.g. all users of group X), and produce grid-mapfile entries
Globus Information Services INFN implemented a hierarchical
structure of GIS based on geographical entities Site GIIS’s Local GRIS’s registered at the site
GIIS Root GIIS where local GIIS’s are
registered
Dc=mi, Dc=infn,dc=it,o=grid
Milano
GIIS GIIS
Dc=pd,Dc=infn,dc=it,o=grid
Top Level INFN GIIS
Dc=infn,dc=it,o=grid
Padova
INFN GIS Topology
GRIS
GIIS
GRIS GRIS GRISGRIS GRIS GRISGRIS GRIS GRIS
GIIS
……..
1st level queryfocus on a set of resources
2nd and 3rd level query Get more updated info
root GIIS
High Availabilityldbm backend (?) GIIS replication (?)
A global view
Scheduling/Resource discovery
Globus Information Services Problems
Performance Querying the root GIIS server, on the worst case
the whole namespace must be searched The overall response time is limited by the
slowest response of a descendant Poor GRIS performance (shell backend)
Example (querying a site GIIS): ~ 1 sec. When cache is on ~ 5-10 sec. When cache expired and GIIS and
GRIS not busy > 1 min. when cache expired and GRIS busy
Globus Information Services Other problems
Pull model Mixed push/pull model more suitable
Security and access controls Any GRIS can register itself to a GIIS No access control when searching the GIS
Fault tolerance No automatic failover mechanisms
Globus Information Services Most of these problems already addressed
or are being addressed with the new MDS development Improved GRIS performance Improved GIIS performance (e.g. support for
GIIS timeouts) Integration of GSI security and access control Support for customized indexes Support for pluggable information providers Support for both registration and invitation …
Globus Information Services Other INFN customisations
INFN-GIS browser Tools (MRTG based) to monitor LDAP
servers Entries returned Connections
On-going MDS-2.1 alpha evaluation
INFN-GIS browser
Resource Management Evaluation of Globus GRAM
Focus on possible use of GRAM as uniform interface to different underlying local resource management systems
Tests with Condor, LSF and PBS as LRMS INFN WAN Condor pool as Globus resource
The model is fine, but lack of “robustness” (needed for real production environments)
Memory leaks in the Globus job manager Fixed: patches provided by our group were fed back to Globus
Scalability (one job manager for each job) Reliability (the job manager is not persistent)
Addressed with the new jobmanager (by Condor team) New resource management architecture foreseen with
GRAM-2
Resource Management Default GRAM Reporter (Information providers) not enough for our
needs (in particular considering PC farms): Many useless attributes (at least for our needs), attributes not
calculated (always defined as 0), some attributes not properly calculated, important information (e.f. needed by a resource broker) missing
We are addressing this problem in the context of the DataGrid Project Submission of Condor jobs to Globus resources
Condor-G Useful as a reliable job submission service
Persistent queue of jobs Logging information Exploitation of the new persistent Globus jobmanager Reliable (two phase commit) submission protocol
GlideIn Evaluation of MPICH-G2 vs. MPICH
Some shortcomings found (lack of support for shared memory, worse latency performance for small messages wrt. MPICH)
Data management Tests with GASS Tests with GridFTP alpha release 2
Capability of resuming an interrupted file transfer successfully tested
Support for the GSI authentication mechanisms successfully tested
Throughput tests Increasing number of parallel streams and fixed file
size Increasing file size and fixed number of streams Increasing TCP buffer size Increasing block size
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 Globus now provides only limited
capabilities (executable staging)
Globus installation tools INFN-GRID Globus installation toolkit
To make easier and more “automatic” the installation of the Globus toolkit
To shorten the installation time (very long using the standard install procedures)
Support for specific customisations and configurations
Quick distribution of patches Support for distribution of new tools and packages
Proven to be successful Used to setup a INFN GRID Testbed and also outside
(CERN, FNAL, …) Used as installation tool for DataGrid Testbed 0
INFN-GRID Installation toolkit Characteristics
Distribution of binary files Distribution of the packages needed to install/use Globus Distribution of various Globus flavoured compilations (kerberos,
MPICH, AFS) Support for the most used platforms in the HENP community (Linux
RH, Solaris) Binary file relocation supported Latest patches included (e.g. fixes for Globus jobmanager memory
leaks) Support for local customisations (hook to support different CA’s,
support for different GIS configurations, support for different LRMS,…)
Support for distribution of new tools and packages (certretrieve, GDMP, …)
Upgrade and uninstall procedures Documentation
New Globus packaging Modular packages for individual
components More open development process Possibility to build and install only
desired packages Simpler customization
Contributions from INFN included
Conclusions The Globus toolkit can provide basic services
useful to create and deploy usable Grids, but various shortcomings and issues must be addressed
Globus developers already addressed/ing most of them Other info
Report on the INFN-GRID Globus Evaluation http://www.infn.it/globus/Docs/infn-globus-evaluation.pdf
Response from Globus team to “Report on the INFN-GRID Globus Evaluation”
http://www.isi.edu/~annc/infn/responsetoinfn.pdf http://www.infn.it/globus