confd logs everything to stdout. You can control the types of messages that get printed by using the -log-level flag and corresponding configuration file settings. See the Configuration Guide for more details.
Example log messages:
2013-11-03T19:04:53-08:00 confd[21356]: INFO SRV domain set to confd.io
2013-11-03T19:04:53-08:00 confd[21356]: INFO Starting confd
2013-11-03T19:04:53-08:00 confd[21356]: INFO etcd nodes set to http://etcd0.confd.io:4001, http://etcd1.confd.io:4001
2013-11-03T19:04:54-08:00 confd[21356]: INFO /tmp/myconf2.conf has md5sum ae5c061f41de8895b6ef70803de9a455 should be 50d4ce679e1cf13e10cd9de90d258996
2013-11-03T19:04:54-08:00 confd[21356]: INFO Target config /tmp/myconf2.conf out of sync
2013-11-03T19:04:54-08:00 confd[21356]: INFO Target config /tmp/myconf2.conf has been updated