One of my colleagues and I have a little confusion between us as to exactly when mapred-site.xml is read. The pages on hadoop.apache.org don't seem to specify it very clearly.
One position is that mapred-site.xml is read by the daemon processes at startup, and so changing a parameter in mapred-site.xml requires bouncing the daemons. The other position is that an individual job's launcher reads the local mapred-site.xml when creating its baseline configuration, so changing a parameter in mapred-site.xml will take effect immediately with the next job launched. Thanks for any help you can give improving our understanding of how these configuration files work.
