I have four ES nodes, one of which is a client, and is streaming archived log data into the cluster.
After upgrading all nodes to 1.6.1.  I restarted my intake script. While it appears to be adding data, it's also feeding this back to stdin. Is this a problem?
Should I make the lightspeed jump to 1.7? Move everyone back to 1.6 ?
Jul 21 11:53:44 ris-webstats01 muo_month_3_cache.sh: /stud/buffer.rb:216:in `buffer_flush'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/stud-0.0.19/lib/stud/buffer.rb:193:in `buffer_flush'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/stud-0.0.19/lib/stud/buffer.rb:159:in `buffer_receive'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-0.2.4-java/lib/logstash/outputs/elasticsearch.rb:426:in `receive'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-1.5.0-java/lib/logstash/outputs/base.rb:88:in `handle'", "(eval):159:in `output_func'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-1.5.0-java/lib/logstash/pipeline.rb:244:in `outputworker'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-1.5.0-java/lib/logstash/pipeline.rb:166:in `start_outputs'"], :level=>:warn}
 I added a third data node, which yum helpfully installed at 1.6.1 which caused issues with shards. The previous three nodes installed, weeks before, with 1.6.0.