I removed three lines and Logstash log is as below :
[2017-07-04T04:16:55,186][INFO ][logstash.outputs.elasticsearch] Elasticsearch pool URLs updated {:changes=>{:removed=>[], :added=>[http://172.30.9.20:9200/]}}
[2017-07-04T04:16:55,190][INFO ][logstash.outputs.elasticsearch] Running health check to see if an Elasticsearch connection is working {:healthcheck_url=>http://172.30.9.20:920
0/, :path=>"/"}
[2017-07-04T04:16:55,274][WARN ][logstash.outputs.elasticsearch] Attempted to resurrect connection to dead ES instance, but got an error. {:url=>#<URI::HTTP:0x2a880895 URL:http
://172.30.9.20:9200/>, :error_type=>LogStash::Outputs::ElasticSearch::HttpClient::Pool::HostUnreachableError, :error=>"Elasticsearch Unreachable: [http://172.30.9.20:9200/][Man
ticore::SocketException] Connection refused (Connection refused)"}
[2017-07-04T04:16:55,275][INFO ][logstash.outputs.elasticsearch] Using mapping template from {:path=>nil}
[2017-07-04T04:16:55,281][WARN ][logstash.outputs.elasticsearch] Marking url as dead. Last error: [LogStash::Outputs::ElasticSearch::HttpClient::Pool::HostUnreachableError] Ela
sticsearch Unreachable: [http://172.30.9.20:9200/][Manticore::SocketException] Connection refused (Connection refused) {:url=>http://172.30.9.20:9200/, :error_message=>"Elastic
search Unreachable: [http://172.30.9.20:9200/][Manticore::SocketException] Connection refused (Connection refused)", :error_class=>"LogStash::Outputs::ElasticSearch::HttpClient
::Pool::HostUnreachableError"}
[2017-07-04T04:16:55,282][ERROR][logstash.outputs.elasticsearch] Failed to install template. {:message=>"Elasticsearch Unreachable: [http://172.30.9.20:9200/][Manticore::Socket
Exception] Connection refused (Connection refused)", :class=>"LogStash::Outputs::ElasticSearch::HttpClient::Pool::HostUnreachableError", :backtrace=>["/usr/share/logstash/vendo
r/bundle/jruby/1.9/gems/logstash-output-elasticsearch-7.3.1-java/lib/logstash/outputs/elasticsearch/http_client/pool.rb:271:in `perform_request_to_url'", "/usr/share/logstash/v
endor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-7.3.1-java/lib/logstash/outputs/elasticsearch/http_client/pool.rb:257:in `perform_request'", "/usr/share/logstash/vend
or/bundle/jruby/1.9/gems/logstash-output-elasticsearch-7.3.1-java/lib/logstash/outputs/elasticsearch/http_client/pool.rb:347:in `with_connection'", "/usr/share/logstash/vendor/
bundle/jruby/1.9/gems/logstash-output-elasticsearch-7.3.1-java/lib/logstash/outputs/elasticsearch/http_client/pool.rb:256:in `perform_request'", "/usr/share/logstash/vendor/bun
dle/jruby/1.9/gems/logstash-output-elasticsearch-7.3.1-java/lib/logstash/outputs/elasticsearch/http_client/pool.rb:264:in `get'", "/usr/share/logstash/vendor/bundle/jruby/1.9/g
ems/logstash-output-elasticsearch-7.3.1-java/lib/logstash/outputs/elasticsearch/http_client.rb:86:in `get_version'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-
output-elasticsearch-7.3.1-java/lib/logstash/outputs/elasticsearch/template_manager.rb:16:in `get_es_version'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-outpu
t-elasticsearch-7.3.1-java/lib/logstash/outputs/elasticsearch/template_manager.rb:20:in `get_es_major_version'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-outp
ut-elasticsearch-7.3.1-java/lib/logstash/outputs/elasticsearch/template_manager.rb:7:in `install_template'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-e
lasticsearch-7.3.1-java/lib/logstash/outputs/elasticsearch/common.rb:57:in `install_template'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-
7.3.1-java/lib/logstash/outputs/elasticsearch/common.rb:24:in `register'", "/usr/share/logstash/logstash-core/lib/logstash/output_delegator_strategies/shared.rb:9:in `register'
", "/usr/share/logstash/logstash-core/lib/logstash/output_delegator.rb:41:in `register'", "/usr/share/logstash/logstash-core/lib/logstash/pipeline.rb:268:in `register_plugin'",
"/usr/share/logstash/logstash-core/lib/logstash/pipeline.rb:279:in `register_plugins'", "org/jruby/RubyArray.java:1613:in `each'", "/usr/share/logstash/logstash-core/lib/logst
ash/pipeline.rb:279:in `register_plugins'", "/usr/share/logstash/logstash-core/lib/logstash/pipeline.rb:288:in `start_workers'", "/usr/share/logstash/logstash-core/lib/logstash
/pipeline.rb:214:in `run'", "/usr/share/logstash/logstash-core/lib/logstash/agent.rb:398:in `start_pipeline'"]}
[2017-07-04T04:16:55,283][INFO ][logstash.outputs.elasticsearch] New Elasticsearch output {:class=>"LogStash::Outputs::ElasticSearch", :hosts=>[#<URI::Generic:0x573db7c0 URL://
172.30.9.20>]}
[2017-07-04T04:16:55,287][INFO ][logstash.pipeline ] Starting pipeline {"id"=>"main", "pipeline.workers"=>8, "pipeline.batch.size"=>125, "pipeline.batch.delay"=>5, "pipe
line.max_inflight"=>1000}
[2017-07-04T04:16:55,490][ERROR][logstash.pipeline ] Error registering plugin {:plugin=>"<LogStash::Inputs::File path=>[\"/var/log/172.30.10.17/messages\"], sincedb_path
=>\"/var/log/logstash\", start_position=>\"beginning\", type=>\"syslog\", tags=>[\"netsyslog\"], id=>\"fa08036ca31fc35ee5eb95f0190efd3fd04f0f29-1\", enable_metric=>true, codec=
><LogStash::Codecs::Plain id=>\"plain_ca00dbf9-ea9a-4c06-b075-a20966b22b26\", enable_metric=>true, charset=>\"UTF-8\">, stat_interval=>1, discover_interval=>15, sincedb_write_i