Use a linked container running Elasticsearch

logstash_linked.conf

input {
  stdin {
    type => "stdin-type"
  }

  file {
    type => "syslog"
    path => [ "/var/log/*.log", "/var/log/messages", "/var/log/syslog" ]
    start_position => "beginning"
  }
}

output {
  stdout {
    codec => rubydebug
  }

  elasticsearch_http {
    host => "ES_HOST"
    port => "ES_PORT"
  }
}