Wednesday, October 10, 2007

Condor Collector Didn't Start

OK, installing Condor on a local set of linux machines with NFS, no firewall problems, and real IP addresses. What could possibly go wrong? Used condor_install, edited the HOSTWRITE_ALLOW param, tried to start with condor_master, but condor_status gave the error

-bash-3.00$ ./bin/condor_status
CEDAR:6001:Failed to connect to
Error: Couldn't contact the condor_collector on

The answer is found in the link below: you have to enable the additional daemons (particularly COLLECTOR) in the condor_config file.

Note this does not apply to firewalled machines with no access to DNS, no real IPs, etc. See my earlier post for this solution.

Why in the world was this not set in the config file for the master node by default?

Sunday, October 07, 2007

NVO Summary

I bookmarked several NVO related links on See my tag role on this blog, or check This blog post is intended to tie these together.

It looks like the Grid Summer Schools in 2004 and 2006 are the best sources for software. Ray Plante's nice but somewhat outdated summary,, is the best primer.

In general, it looks like one needs to do the following:
  • Get some data.
  • Set up a registry. NCSA's VORegistry-in-a-box looks like the best available software. They also interestingly seem to build on the Digital Library's OAI software.
  • Set up some data services. The simplest is a Cone Search service. This is available from the 2004 Summer School. This uses HTTP GET/URLS/REST, and apparently returns a list of links to existing whole images in the archive.
  • The SAIP service (aka SAI service) seems to be also available in the 2004 download. This implements the Simple Image Access Protocol. The services are typically HTTP GET/REST based but support more arguments that the Cone Service. For example, you can request image cutouts and other things that are created and returned on the fly, not just whole images.
  • The OpenSkyNode service is yet another service interface. This looks like it supports more complicated, SQL-like queries and can query multiple servers. But the JSkyNode software that Ray Plante mentions is no longer available.
For actually building the database, Roy Williams suggested

Tuesday, October 02, 2007

Better TeraGrid Single Sign On

Through the invisible hand of market forces, the world inevitably becomes optimized over time. Witness This supersedes my earlier post,