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Maximilian Berger
David Gstir
Thomas Fahringer
Distributed and parallel Systems Group
University of Innsbruck
Austria
Oct, 13, 2009. Krakow, PL.
Outline
 Motivation
 Architecture
 Example Use Case
 Conclusions
Motivation
 The Grid is heterogeneous
 Clusters are (mostly) homogeneous
 Multiple Architectures, Distributions, Versions,
Libraries
 32 / 64 Bit
 Intel / Sparc
 Linux / Solaris
 SL Linux, Redhat, Debian, etc.
 Will my software run on this Grid site?
Possible Solutions
 Homogenization
 Make all sites equal


Same Hardware
Same Software
 Partially done in EGEE (Scientific Linux, fixed version)
 Virtualization
 Provide a virtual machine which provides a known
environment
 Large Overhead!
Possible Solutions (cont.)
 Resource Descriptions
 Every Resource published information about itself
 Grid middleware uses this information to select sites
 Example: GLUE schema
 Problem:


Often Incomplete!
Mostly done manually
 Automated Software detection
 Automatic detect installed software
 Provide this information back to the user
Softcrawl Architecture
Crawler
 Contains a list of plug-ins
 Each plug-in describes
 Key-Value pairs about software
 Test script
 Parser component
 Results are stored in database (e.g. BDII)
 Tests are run periodically
 In the context of a normal user
 Multiple tests can be combined into one Grid job
Example Use Case
 Java Runtime Environment
 Application is written in Java
 Is Java installed?
 If so, which Version?
 Does JAVA_HOME point to a valid location?
 Prototype implementation
 Uses internal DB
 Runs in context of a personal user
Example Use Case: Script
#!/bin/sh
echo "-- WHICH OUTPUT BEGIN --"
which java
echo "-- WHICH OUTPUT END --"
echo "-- VERSION OUTPUT BEGIN --"
`which java` -version
echo "-- VERSION OUTPUT END --"
echo "-- JAVA_HOME OUTPUT BEGIN --"
echo $JAVA_HOME
echo "-- JAVA_HOME OUTPUT END --"
echo "-- JAVA_HOME_VALID OUTPUT BEGIN --"
[ -x $JAVA_HOME/bin/java ] && echo true || echo
false
echo "-- JAVA_HOME_VALID OUTPUT END --"
Example Use Case: Values
Key
Example Value
Type
Environment.java_home.
exists
True
Boolean
Java.binary.path
/usr/lib/jvm/java/bin/java
String
Environment.java_home.
valid
True
Boolean
Environment.java_home.
value
/usr/lib/jvm/java
String
Java.version.number
16013.0
Double
Java.version.string
java version "1.6.0 13" Java (TM) SE
Runtime Environment (build 1.6.0 13b03) Java HotSpot(TM) Server VM
(build 11.3-b02, mixed mode)
String
Example Use Case: Results
Conclusions
 Homogenization is not an option
 Software description helps
 Software description must be automated
 Users must be able to create tests
 Prototype implementation successful
 Collected data can be used to create better resource
descriptions
 Jobs are now only run on sites where they actually
work!