Logstash webhdfs output error

here is the config:
input {
redis {
host => "127.0.0.1"
port => "6379"
key => "abc"
data_type => "list"
codec => "plain"
}
}
output {

webhdfs {
host => "192.168.xx.xxx"
path => "/abc.log"
user => "hdfs"
}
the error info:
Failed to flush outgoing items {:outgoing_count=>500, :exception=>"NoMethodError", :backtrace=>["/opt/logstash-2.3.4/vendor/bundle/jruby/1.9/gems/logstash-core-event-2.3.4-java/lib/logstash/event.rb:105:in to_s'", "/opt/logstash-2.3.4/vendor/bundle/jruby/1.9/gems/logstash-codec-line-2.1.2/lib/logstash/codecs/line.rb:56:inencode'", "/opt/logstash-2.3.4/vendor/bundle/jruby/1.9/gems/logstash-output-webhdfs-2.0.4/lib/logstash/outputs/webhdfs.rb:179:in flush'", "org/jruby/RubyArray.java:2409:incollect'", "/opt/logstash-2.3.4/vendor/bundle/jruby/1.9/gems/logstash-output-webhdfs-2.0.4/lib/logstash/outputs/webhdfs.rb:173:in flush'", "/opt/logstash-2.3.4/vendor/bundle/jruby/1.9/gems/stud-0.0.22/lib/stud/buffer.rb:219:inbuffer_flush'", "org/jruby/RubyHash.java:1342:in each'", "/opt/logstash-2.3.4/vendor/bundle/jruby/1.9/gems/stud-0.0.22/lib/stud/buffer.rb:216:inbuffer_flush'", "/opt/logstash-2.3.4/vendor/bundle/jruby/1.9/gems/stud-0.0.22/lib/stud/buffer.rb:193:in buffer_flush'", "/opt/logstash-2.3.4/vendor/bundle/jruby/1.9/gems/stud-0.0.22/lib/stud/buffer.rb:159:inbuffer_receive'", "/opt/logstash-2.3.4/vendor/bundle/jruby/1.9/gems/logstash-output-webhdfs-2.0.4/lib/logstash/outputs/webhdfs.rb:166:in receive'", "/opt/logstash-2.3.4/vendor/bundle/jruby/1.9/gems/logstash-core-2.3.4-java/lib/logstash/outputs/base.rb:83:inmulti_receive'", "org/jruby/RubyArray.java:1613:in each'", "/opt/logstash-2.3.4/vendor/bundle/jruby/1.9/gems/logstash-core-2.3.4-java/lib/logstash/outputs/base.rb:83:inmulti_receive'", "/opt/logstash-2.3.4/vendor/bundle/jruby/1.9/gems/logstash-core-2.3.4-java/lib/logstash/output_delegator.rb:130:in worker_multi_receive'", "/opt/logstash-2.3.4/vendor/bundle/jruby/1.9/gems/logstash-core-2.3.4-java/lib/logstash/output_delegator.rb:114:inmulti_receive'", "/opt/logstash-2.3.4/vendor/bundle/jruby/1.9/gems/logstash-core-2.3.4-java/lib/logstash/pipeline.rb:301:in output_batch'", "org/jruby/RubyHash.java:1342:ineach'", "/opt/logstash-2.3.4/vendor/bundle/jruby/1.9/gems/logstash-core-2.3.4-java/lib/logstash/pipeline.rb:301:in output_batch'", "/opt/logstash-2.3.4/vendor/bundle/jruby/1.9/gems/logstash-core-2.3.4-java/lib/logstash/pipeline.rb:232:inworker_loop'", "/opt/logstash-2.3.4/vendor/bundle/jruby/1.9/gems/logstash-core-2.3.4-java/lib/logstash/pipeline.rb:201:in `start_workers'"], :level=>:warn}

Looks like it can't connect for some reason.
Try checking the logs on the web HDFS side?

@warkolm. thanks. I have checked the web hdfs and i works well . I have create a issue, https://github.com/elastic/logstash/issues/5664 . Thanks a lot for your feedback.