title: EFK system is build on docker but fluentd can't start up
body: <p>I want to build the efk logger system by docker compose.
  Everything is setup, only fluentd has problem.</p>
  <p>fluentd docker container logs</p>
  <blockquote>
  <p>2022-02-15 02:06:11 +0000 [info]: parsing config file is succeeded path=&quot;/fluentd/etc/fluent.conf&quot;</p>
  </blockquote>
  <blockquote>
  <p>2022-02-15 02:06:11 +0000 [info]: gem 'fluent-plugin-elasticsearch' version '5.0.3'</p>
  </blockquote>
  <blockquote>
  <p>2022-02-15 02:06:11 +0000 [info]: gem 'fluentd' version '1.12.0'</p>
  </blockquote>
  <blockquote>
  <p>/usr/local/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require': cannot load such file -- elasticsearch/transport/transport/connections/selector (LoadError)</p>
  </blockquote>
  <p>my directory:<br></p>
  <pre>
   my project/
   ├─ fluentd/
   │  ├─ conf/
   │  │  └── fluent.conf
   │  └── Dockerfile
   └── docker-compose.yml
  </pre>
  <p>docker-compose.yml:</p>
  <pre><code>version: &quot;3&quot;
  services:
    web:
      image: httpd
      ports:
        - &quot;8010:80&quot;
      depends_on:
        - fluentd
      logging:
        driver: &quot;fluentd&quot;
        options:
          fluentd-address: 127.0.0.1:24224
          fluentd-async: 'true'
          tag: httpd.access
  
    fluentd:
      build: ./fluentd
      volumes:
        - ./fluentd/conf:/fluentd/etc
      links:
        - &quot;elasticsearch&quot;
      ports:
        - &quot;24224:24224&quot;
        - &quot;24224:24224/udp&quot;
  
    elasticsearch:
      image: docker.elastic.co/elasticsearch/elasticsearch:7.13.1
      environment:
        - discovery.type=single-node
      expose:
        - 9200
      ports:
        - &quot;9200:9200&quot;
  
    kibana:
      image: docker.elastic.co/kibana/kibana:7.13.1
      links:
        - &quot;elasticsearch&quot;
      ports:
        - &quot;5601:5601&quot;
  </code></pre>
  <p>Dockerfile:</p>
  <pre><code># fluentd/Dockerfile
  
  FROM fluent/fluentd:v1.12.0-debian-1.0
  USER root
  RUN [&quot;gem&quot;, &quot;install&quot;, &quot;fluent-plugin-elasticsearch&quot;, &quot;--no-document&quot;, &quot;--version&quot;, &quot;5.0.3&quot;]
  USER fluent
  </code></pre>
  <p>fluent.conf:</p>
  <pre><code>&lt;source&gt;
    @type forward
    port 24224
    bind 0.0.0.0
  &lt;/source&gt;
  
  &lt;match *.**&gt;
    @type copy
  
    &lt;store&gt;
      @type elasticsearch
      host elasticsearch
      port 9200
      logstash_format true
      logstash_prefix fluentd
      logstash_dateformat %Y%m%d
      include_tag_key true
      type_name access_log
      tag_key @log_name
      flush_interval 1s
    &lt;/store&gt;
  
    &lt;store&gt;
      @type stdout
    &lt;/store&gt;
  &lt;/match&gt;
  </code></pre>