Logstash now constantly restarts and I see the below in the log file:
[2018-01-02T10:56:39,851][INFO ][logstash.pipeline ] Pipeline started {"pipeline.id"=".monitoring-logstash"}
[2018-01-02T10:56:39,865][DEBUG][logstash.pipeline ] Pipeline started successfully {:pipeline_id=".monitoring-logstash", :thread="#<Thread:0x7f8d6a78@/usr/share/logstash/logstash-core/lib/logstash/pipeline.rb:245 sleep"}
[2018-01-02T10:56:39,875][DEBUG][logstash.inputs.metrics ] Metric: input started
[2018-01-02T10:56:39,876][DEBUG][logstash.agent ] Executing action {:action=LogStash::PipelineAction::Create/pipeline_id:main}
[2018-01-02T10:56:39,985][DEBUG][logstash.plugins.registry] On demand adding plugin to the registry {:name="gelf", :type="input", :class=LogStash::Inputs::Gelf}
[2018-01-02T10:56:39,996][DEBUG][logstash.codecs.plain ] config LogStash::Codecs::Plain/@id = "plain_a9a9778b-28bd-4bbf-b6fb-8adf0d87403c"
[2018-01-02T10:56:39,996][DEBUG][logstash.codecs.plain ] config LogStash::Codecs::Plain/@enable_metric = true
[2018-01-02T10:56:39,996][DEBUG][logstash.codecs.plain ] config LogStash::Codecs::Plain/@charset = "UTF-8"
[2018-01-02T10:56:39,997][DEBUG][logstash.inputs.gelf ] config LogStash::Inputs::Gelf/@host = "10.16.0.5"
[2018-01-02T10:56:40,003][DEBUG][logstash.inputs.gelf ] config LogStash::Inputs::Gelf/@port = 20001
[2018-01-02T10:56:40,003][DEBUG][logstash.inputs.gelf ] config LogStash::Inputs::Gelf/@id = "5513518de419a8d7b427ec0c405c91bdfdde4e4dffad0f8405fbdcb43ad59dfa"
[2018-01-02T10:56:40,004][DEBUG][logstash.inputs.gelf ] config LogStash::Inputs::Gelf/@enable_metric = true
[2018-01-02T10:56:40,004][DEBUG][logstash.inputs.gelf ] config LogStash::Inputs::Gelf/@codec = <LogStash::Codecs::Plain id="plain_a9a9778b-28bd-4bbf-b6fb-8adf0d87403c", enable_metric=true, charset="UTF-8"
[2018-01-02T10:56:40,005][DEBUG][logstash.inputs.gelf ] config LogStash::Inputs::Gelf/@add_field = {}
[2018-01-02T10:56:40,005][DEBUG][logstash.inputs.gelf ] config LogStash::Inputs::Gelf/@remap = true
[2018-01-02T10:56:40,005][DEBUG][logstash.inputs.gelf ] config LogStash::Inputs::Gelf/@strip_leading_underscore = true
[2018-01-02T10:56:40,027][DEBUG][logstash.codecs.plain ] config LogStash::Codecs::Plain/@id = "plain_6f903927-fa53-4b40-abdd-887858cd9087"
[2018-01-02T10:56:40,031][DEBUG][logstash.codecs.plain ] config LogStash::Codecs::Plain/@enable_metric = true
[2018-01-02T10:56:40,031][DEBUG][logstash.codecs.plain ] config LogStash::Codecs::Plain/@charset = "UTF-8"
[2018-01-02T10:56:40,033][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@hosts = [//localhost:9200]
[2018-01-02T10:56:40,034][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@manage_template = false
[2018-01-02T10:56:40,034][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@index = "{[@metadata][beat]}-%{+YYYY.MM.dd}"
[2018-01-02T10:56:40,034][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@id = "a4707d34ff738ec7e975755a13e91ab8d8fe807e3ffb685279a8c0015a0008a6"
[2018-01-02T10:56:40,034][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@enable_metric = true
[2018-01-02T10:56:40,034][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@codec = <LogStash::Codecs::Plain id="plain_6f903927-fa53-4b40-abdd-887858cd9087", enable_metric=true, charset="UTF-8"
[2018-01-02T10:56:40,034][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@workers = 1
[2018-01-02T10:56:40,034][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@template_name = "logstash"
[2018-01-02T10:56:40,034][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@template_overwrite = false
[2018-01-02T10:56:40,034][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@parent = nil
[2018-01-02T10:56:40,034][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@join_field = nil
[2018-01-02T10:56:40,034][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@upsert = ""
[2018-01-02T10:56:40,034][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@doc_as_upsert = false
[2018-01-02T10:56:40,040][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@script = ""
[2018-01-02T10:56:40,040][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@script_type = "inline"
[2018-01-02T10:56:40,040][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@script_lang = "painless"
[2018-01-02T10:56:40,040][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@script_var_name = "event"
[2018-01-02T10:56:40,040][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@scripted_upsert = false
[2018-01-02T10:56:40,040][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@retry_initial_interval = 2
[2018-01-02T10:56:40,040][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@retry_max_interval = 64
[2018-01-02T10:56:40,041][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@retry_on_conflict = 1
[2018-01-02T10:56:40,041][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@pipeline = nil
[2018-01-02T10:56:40,041][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@action = "index"
[2018-01-02T10:56:40,041][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@ssl_certificate_verification = true
[2018-01-02T10:56:40,041][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@sniffing = false
[2018-01-02T10:56:40,041][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@sniffing_delay = 5
[2018-01-02T10:56:40,041][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@timeout = 60
[2018-01-02T10:56:40,041][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@failure_type_logging_whitelist = []
[2018-01-02T10:56:40,041][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@pool_max = 1000
[2018-01-02T10:56:40,041][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@pool_max_per_route = 100
[2018-01-02T10:56:40,041][DEBUG][logstash.outputs.elasticsearch] config LogStash::Outputs::ElasticSearch/@resurrect_delay = 5