Syslog-ng (syslog "Next Generation") is an alternative to the syslog that comes default with most Linux distributions. Conceptually it is very similar to syslog: it collects logs from applications via a simple communication protocol and dumps them into log files. It's nicer than the default because it is more configurable, fancier, and does a nicer job of forwarding the logs to other computers, if that is desired.
Syslog-ng is in the VDT because it is used by Open Science Grid (OSG) sites. It is used alongside the system-installed syslog, so it is minimally intrusive. OSG configures syslog-ng to forward logs to a central location for troubleshooting purposes.
We ship syslog-ng with two interesting modifications. First, we ship a
modified version of the logger program that feeds log
messages to syslog.
Our
modification is a simple change to increase the allowable size for
a log message. We also ship an "injector" which reads log files and
pipes them to logger. While the basic process isn't surprising (it's
tail -F | logger), it watches over these processes to
make sure that they keep running.
We don't ship syslog-ng with OSG-specific configuration, but provide a script to configure it.