SONG%20Cluster%20Software

1
SONG Cluster Software

• A few elements of the SONG software
• principles
• Søren Frandsen, Jonas B. Nielsen
• and Mads Fredslund Andersen
• Aarhus University

2
Simplified Architecture
Remote Site 1
Remote Site 2
Remote Site 3
Central Site
Remote Site 4
Remote Site 8
Remote Site 7
Remote Site 6
Remote Site 5

• Flow Both data and files

3
Requirements

• All communication between sites via the database
• One central site and eight remote sites
• Central site center of communication (a star
  architecture)
• Autonymous remote sites
• Continue work if communication is lost
• Eventually consistent
• Open-source tools
• Linux based

4
Major Software Component

• DBMS PostgreSQL http//www.postgresql.org/
• Database Replication Slony-I http//slony.info/
• File Replication GlusterFShttp//www.gluster.org/
  
• All
• Open source projects/products
• Mature projects
• Good release cyclus
• Good documentation

5
Database Replication, Overview
Central Node
Remote Node 2
Remote Node 1
6
dispatcher
dispatcher
slony
checker
scheduler
worker
slony
Work processes
...
...
house hold
Central Site
Remote Site n
Telescope
Weather
7
Ordering an observation Observing requests
Central OR_handler.py Site 1 OR_executer.py