EDGI project partner CNRS from the Laboratoire de l'Accélérateur Linéaire in Orsay, France has released the XtremWeb-HEP 8.1.2 version.
Major points in this version include:
- Correction: inter node communication thanks to Jason Maassen from the Netherlands eScience Center in Amsterdam
- Correction: REST interface
- New feature: the server embeds Web service available through HTTPS
A. Corrections:
- A.1 on server side, the scheduling improved: hosts.incomingconnection is now taken into account to ensure a server like job is not sent to a volunteer resource where incoming connections are not allowed
- A.2 on server side, the scheduling improved: restoring a feature from XtremWeb 1.8.0 by INRIA: "expected host" so that the end user can specify at submission time the expected volunteer resource to run the job. Note that if the expected host does not request a job or does not match the requirements (OS, CPU, ...), the job is never computed.
- A.3 the DG to SG bridge is now compatible with shared applications so that one can use VirtualBox on EGI resources
- A.4 some bugs corrected on client side regarding application registration and task management
- A.5 a bug corrected on temporary file usage: they are now cleaned at software exit
- A.6 the REST interface has been completely rewritten. The <xwhep></xwhep> root element MUST be used. Ex:
a/ to send a new application: https://server/sendapp/?XWPARAM=<xwhep version="8.0.2-flyinggrid"><app name="pouet" /></xwhep>
b/ to retrieved registered applications: https://server/getapps
- A.7 a bug corrected in HTTP data download
- A.8 SmartSocket usage corrected; inter node communications fully functional now
B. New features:
- B.1 the creation of new Live CD can be customized
- this is done by providing several optional files:
- > a text file 'user.packages' may be provided to install custom packages: this file must contain a space separated packages list
- > a text file 'user.hostname' may be provided to customize the LiveCD hostname: this file must contain the host name only
- > any package files are installed on the fly (*.rpm or *.deb, depending on the LiveCD OS)
- B.2 the client can now be used to create SmartSockets end point, independently of any task
- this may be useful to create SmartSockets tunnel from a running VM to the client PC
- > e.g. mount the client FS inside the running VM
- B.3 a new Mac OS X package "xwhep.vworker" to deploy the middleware inside a VM
- B.4 the server contains an embedded Web service interface available through HTTPS
C. Known Bugs:
- C.1 xtremweb.gmond.pl does not scale
- C.2 the scheduler is not fair
- C.3 there may be some concurrent access problems leading to some errors
There may be two concurrent access problems
- on server side, DB access may lead to inconsistency between works and tasks tables
This could certainly be solved using SQL transactions
But we would then need MySQL >=5
There are sime issues with transactions with hsqldb
- on worker side, file access if a worker is configured to run jobs in parallel (default one thread per CPU core)
CNRS has observed that these concurrent access problems may lead to up to 6% erroneous jobs. Until further notification, CNRS considers this rate acceptable.
More information is available at http://www.xtremweb-hep.org/spip.php?rubrique15