FAQ: lcg-ce to cream-ce
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The FAQ provides the questions and answers those may arise for the user communities during the transition from lcg-ce to cream-ce. It does not replace the CREAM User Guide (see the references section), but it provides a list of pointers to relevant documentation.
Q1: What is cream-ce?
The CREAM (Computing Resource Execution And Management) Service is a simple, lightweight service that implements all the operations at the Computing Element (CE) level; its well-defined Web Service-based interface and its implementation as an extension of the Java-Axis servlet (running inside the Apache Tomcat container) provide interoperability with clients written in any programming language and running on any computer platform.
The CREAM interface is well-defined using the Web Service Description Language (WSDL); anyone can generate his/her CREAM client by simply filling in the stub code generated by WSDL parser (gSOAP for C/C++, Axis for Java, Perl module for perl).
The CREAM architecture is illustrated here: Diagram
Q2: What batch systems are supported by CREAM?
LSF, Torque
Q3: How does proxy credential delegation and proxy renewal work in CREAM?
Detailed documentation about security-related aspects of CREAM are available at the CREAM User Guide.
Q4: how are jobs submitted to CREAM? CREAM has ability to accept either direct Jobs from gLite-UI, SOAP clients or any other developed UIs based on web-services or Jobs sent through WMS. Jobs can be controlled through operations such as suspend, resume and delete.
In case of submission through the Workload Management System (WMS), the ICE (Interface to CREAM Environment) component of the WMS is used. To select the CREAM instances to which the job can be submitted, submission criteria can be defined by means of the Job Description Language - JDL (see the CREAM JDL Guide).
Jobs Control
SandBox Management
Storage Element (SE)
- gridftp
CREAM-CE Information
Benchmarks
Jobs Submission
Direct Jobs Submission
- Jobs States Notifications
WMS Jobs Submission
- Jobs States Notifications
CREAM-CE Performance
CREAM Client Errors
Known Issues
Known Issues of current CREAM software in production release.
Known Issues of WMS ICE component
Q: Where can I find more documentation about CREAM?
- Interworking between CREAM and the ICE component
- CREAM Homepage
- CREAM User's Guide
- Other Guides
- CREAM Job state diagram
- WMS ICE Architecture
- More About CREAM ICE
CREAM mailing lists
- cream-support AT lists.infn.it