Elasticsearch Unreachable: connection rejected

I have an ELK stack running inside docker containers inside a virtual machine.
I can curl

stuff for ES and it shows up in Kibana just fine.
I can read files using Logstash and output them to stdout.
But Logstash cannot send data to ES

docker-compose.yml

version: '2'
services:
  elasticsearch:
    image: elasticsearch
    ports:
      - "9200:9200"
      - "9300:9300"
    environment:
      ES_JAVA_OPTS: "-Xmx256m -Xms256m"
      xpack.security.enabled: "false"
      xpack.monitoring.enabled: "false"
      xpack.graph.enabled: "false"
      xpack.watcher.enabled: "false"
    networks:
      - elk

  logstash:
    image: docker.elastic.co/logstash/logstash:5.3.2
    volumes:
      - ./logstash/config/logstash.yml:/usr/share/logstash/config/logstash.yml
      - ./logstash/pipeline:/usr/share/logstash/pipeline
      - ./data:/usr/share/data
    ports:
      - "5000:5000"
      - "9600:9600"
    networks:
      - elk
    depends_on:
      - elasticsearch

  kibana:
    # kibana config

networks:
  elk:
    driver: bridge

      

        
        
        
      

    

logstash.yml

(enabling or disabling xpack doesn't seem to matter)

#log.level: debug
xpack.monitoring.elasticsearch.password: changeme
xpack.monitoring.elasticsearch.username: logstash_system
xpack.monitoring.elasticsearch.url: http://127.0.0.1:9200
xpack.monitoring.enabled: false

      

        
        
        
      

    

pipeline.conf

input {
# some files
}
filter{
# csv filter
}
output {
    if ([type] == "GPS") {
      stdout { }
      elasticsearch {
          hosts => [ "127.0.0.1:9200" ]
          index => "GPS"
          template_overwrite => true
          user => logstash_system
          password => changeme
      }
    }
}

      

        
        
        
      

    

Output docker-compose up

elasticsearch_1  [2017-05-03T05:06:29,821][INFO ][o.e.n.Node               ] initialized
elasticsearch_1  [2017-05-03T05:06:29,821][INFO ][o.e.n.Node               ] [SzDlw_j] starting ...
elasticsearch_1  [2017-05-03T05:06:30,352][WARN ][i.n.u.i.MacAddressUtil   ] Failed to find a usable hardware address from the network interfaces; using random bytes: 74:70:60:88:e2:f8:41:36
elasticsearch_1  [2017-05-03T05:06:30,722][INFO ][o.e.t.TransportService   ] [SzDlw_j] publish_address {127.0.0.1:9300}, bound_addresses {[::1]:9300}, {127.0.0.1:9300}
elasticsearch_1  [2017-05-03T05:06:30,744][WARN ][o.e.b.BootstrapChecks    ] [SzDlw_j] max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]
elasticsearch_1  [2017-05-03T05:06:34,027][INFO ][o.e.c.s.ClusterService   ] [SzDlw_j] new_master {SzDlw_j}{SzDlw_jiQsWcXN00BZfZHQ}{ELB1oDR4SlW6atQIM88hfg}{127.0.0.1}{127.0.0.1:9300}, reason: zen-disco-elected-as-master ([0] nodes joined)
elasticsearch_1  [2017-05-03T05:06:34,176][INFO ][o.e.h.n.Netty4HttpServerTransport] [SzDlw_j] publish_address {172.18.0.2:9200}, bound_addresses {[::]:9200}
elasticsearch_1  [2017-05-03T05:06:34,179][INFO ][o.e.n.Node               ] [SzDlw_j] started
elasticsearch_1  [2017-05-03T05:06:34,832][INFO ][o.e.g.GatewayService     ] [SzDlw_j] recovered [1] indices into cluster_state
elasticsearch_1  [2017-05-03T05:06:36,519][INFO ][o.e.c.r.a.AllocationService] [SzDlw_j] Cluster health status changed from [RED] to [YELLOW] (reason: [shards started [[.kibana][0]] ...]).
logstash_1       Sending Logstash logs to /usr/share/logstash/logs which is now configured via log4j2.properties
logstash_1       [2017-05-03T05:06:55,865][INFO ][logstash.outputs.elasticsearch] Elasticsearch pool URLs updated {:changes=>{:removed=>[], :added=>[http://127.0.0.1:9200/]}}
logstash_1       [2017-05-03T05:06:55,887][INFO ][logstash.outputs.elasticsearch] Running health check to see if an Elasticsearch connection is working {:healthcheck_url=>http://127.0.0.1:9200/, :path=>"/"}
logstash_1       [2017-05-03T05:06:56,131][WARN ][logstash.outputs.elasticsearch] Attempted to resurrect connection to dead ES instance, but got an error. {:url=>#<URI::HTTP:0x7b0aac02 URL:http://127.0.0.1:9200/>, :error_type=>LogStash::Outputs::ElasticSearch::HttpClient::Pool::HostUnreachableError, :error=>"Elasticsearch Unreachable: [http://127.0.0.1:9200/][Manticore::SocketException] Connection refused (Connection refused)"}
logstash_1       [2017-05-03T05:06:56,140][INFO ][logstash.outputs.elasticsearch] Using mapping template from {:path=>nil}
logstash_1       [2017-05-03T05:06:56,147][WARN ][logstash.outputs.elasticsearch] Marking url as dead. Last error: [LogStash::Outputs::ElasticSearch::HttpClient::Pool::HostUnreachableError] Elasticsearch Unreachable: [http://127.0.0.1:9200/][Manticore::SocketException] Connection refused (Connection refused) {:url=>http://127.0.0.1:9200/, :error_message=>"Elasticsearch Unreachable: [http://127.0.0.1:9200/][Manticore::SocketException] Connection refused (Connection refused)", :error_class=>"LogStash::Outputs::ElasticSearch::HttpClient::Pool::HostUnreachableError"}
logstash_1       [2017-05-03T05:06:56,148][ERROR][logstash.outputs.elasticsearch] Failed to install template. {:message=>"Elasticsearch Unreachable: [http://127.0.0.1:9200/][Manticore::SocketException] Connection refused (Connection refused)", :class=>"LogStash::Outputs::ElasticSearch::HttpClient::Pool::HostUnreachableError", :backtrace=>["/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-6.3.0-java/lib/logstash/outputs/elasticsearch/http_client/pool.rb:287:in `perform_request_to_url'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-6.3.0-java/lib/logstash/outputs/elasticsearch/http_client/pool.rb:273:in `perform_request'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-6.3.0-java/lib/logstash/outputs/elasticsearch/http_client/pool.rb:363:in `with_connection'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-6.3.0-java/lib/logstash/outputs/elasticsearch/http_client/pool.rb:272:in `perform_request'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-6.3.0-java/lib/logstash/outputs/elasticsearch/http_client/pool.rb:280:in `get'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-6.3.0-java/lib/logstash/outputs/elasticsearch/http_client.rb:83:in `get_version'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-6.3.0-java/lib/logstash/outputs/elasticsearch/template_manager.rb:16:in `get_es_version'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-6.3.0-java/lib/logstash/outputs/elasticsearch/template_manager.rb:20:in `get_es_major_version'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-6.3.0-java/lib/logstash/outputs/elasticsearch/template_manager.rb:7:in `install_template'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-6.3.0-java/lib/logstash/outputs/elasticsearch/common.rb:54:in `install_template'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-6.3.0-java/lib/logstash/outputs/elasticsearch/common.rb:21:in `register'", "/usr/share/logstash/logstash-core/lib/logstash/output_delegator_strategies/shared.rb:8:in `register'", "/usr/share/logstash/logstash-core/lib/logstash/output_delegator.rb:41:in `register'", "/usr/share/logstash/logstash-core/lib/logstash/pipeline.rb:257:in `register_plugin'", "/usr/share/logstash/logstash-core/lib/logstash/pipeline.rb:268:in `register_plugins'", "org/jruby/RubyArray.java:1613:in `each'", "/usr/share/logstash/logstash-core/lib/logstash/pipeline.rb:268:in `register_plugins'", "/usr/share/logstash/logstash-core/lib/logstash/pipeline.rb:277:in `start_workers'", "/usr/share/logstash/logstash-core/lib/logstash/pipeline.rb:207:in `run'", "/usr/share/logstash/logstash-core/lib/logstash/agent.rb:389:in `start_pipeline'"]}
logstash_1       [2017-05-03T05:06:56,149][INFO ][logstash.outputs.elasticsearch] New Elasticsearch output {:class=>"LogStash::Outputs::ElasticSearch", :hosts=>[#<URI::Generic:0x6d11738 URL://127.0.0.1:9200>]}
logstash_1       [2017-05-03T05:06:56,163][INFO ][logstash.pipeline        ] Starting pipeline {"id"=>"main", "pipeline.workers"=>1, "pipeline.batch.size"=>125, "pipeline.batch.delay"=>5, "pipeline.max_inflight"=>125}
logstash_1       [2017-05-03T05:06:56,703][INFO ][logstash.pipeline        ] Pipeline main started
logstash_1       2017-05-03T05:06:56.776Z b68ff5316e02 time,lat,lon,elevation,accuracy,bearing,speed
logstash_1       2017-05-03T05:06:56.778Z b68ff5316e02 2014-09-14T00:26:23Z,98.404222,99.999021,9.599976,44.000000,0.000000,0.000000
logstash_1       2017-05-03T05:06:56.779Z b68ff5316e02 2014-09-14T00:48:45Z,98.404297,99.999338,9.000000,35.000000,102.300003,0.500000
logstash_1       [2017-05-03T05:06:57,035][INFO ][logstash.agent           ] Successfully started Logstash API endpoint {:port=>9600}
logstash_1       [2017-05-03T05:06:57,058][WARN ][logstash.outputs.elasticsearch] UNEXPECTED POOL ERROR {:e=>#<LogStash::Outputs::ElasticSearch::HttpClient::Pool::NoConnectionAvailableError: No Available connections>}
logstash_1       [2017-05-03T05:06:57,069][ERROR][logstash.outputs.elasticsearch] Attempted to send a bulk request to elasticsearch, but no there are no living connections in the connection pool. Perhaps Elasticsearch is unreachable or down? {:error_message=>"No Available connections", :class=>"LogStash::Outputs::ElasticSearch::HttpClient::Pool::NoConnectionAvailableError", :will_retry_in_seconds=>2}
logstash_1       [2017-05-03T05:06:59,085][WARN ][logstash.outputs.elasticsearch] UNEXPECTED POOL ERROR {:e=>#<LogStash::Outputs::ElasticSearch::HttpClient::Pool::NoConnectionAvailableError: No Available connections>}
logstash_1       [2017-05-03T05:06:59,086][ERROR][logstash.outputs.elasticsearch] Attempted to send a bulk request to elasticsearch, but no there are no living connections in the connection pool. Perhaps Elasticsearch is unreachable or down? {:error_message=>"No Available connections", :class=>"LogStash::Outputs::ElasticSearch::HttpClient::Pool::NoConnectionAvailableError", :will_retry_in_seconds=>4}
logstash_1       [2017-05-03T05:07:01,146][INFO ][logstash.outputs.elasticsearch] Running health check to see if an Elasticsearch connection is working {:healthcheck_url=>http://127.0.0.1:9200/, :path=>"/"}
logstash_1       [2017-05-03T05:07:01,158][WARN ][logstash.outputs.elasticsearch] Attempted to resurrect connection to dead ES instance, but got an error. {:url=>#<URI::HTTP:0x7b0aac02 URL:http://127.0.0.1:9200/>, :error_type=>LogStash::Outputs::ElasticSearch::HttpClient::Pool::HostUnreachableError, :error=>"Elasticsearch Unreachable: [http://127.0.0.1:9200/][Manticore::SocketException] Connection refused (Connection refused)"}

      

        
        
        
      

    

then it continues the cycle between "sending a bulk request", "performing a health check", "trying to resurrect" and "empty pool error".
With log.level: debug

every time after a while I also seeError, cannot retrieve cgroups information {:exception=>"Errno::ENOENT", :message=>"No such file or directory - /sys/fs/cgroup/cpuacct/system.slice/docker-<containerId>.scope/cpuacct.usage"}