コンテナ内でfluentd実行したら"unexpected error error_class=Errno::EADDRINUSE"でエラッた話

# はじめに
書いた記事の続き？にあたるもの
https://qiita.com/arata-honda/items/03d6da7c9f84f67466a9

# エラー内容
```bash

2020-02-17 11:21:26 +0900 [error]: #0 suppressed same stacktrace
2020-02-17 11:21:26 +0900 [info]: Worker 0 finished unexpectedly with status 1
2020-02-17 11:21:26 +0900 [info]: adding match in @mainstream pattern="docker.**" type="file"
2020-02-17 11:21:26 +0900 [warn]: #0 [output_docker1] 'time_format' specified without 'time_key', will be ignored
2020-02-17 11:21:26 +0900 [info]: adding match in @mainstream pattern="**" type="file"
2020-02-17 11:21:26 +0900 [warn]: #0 [output1] 'time_format' specified without 'time_key', will be ignored
2020-02-17 11:21:26 +0900 [info]: adding filter pattern="**" type="stdout"
2020-02-17 11:21:26 +0900 [info]: adding source type="forward"
2020-02-17 11:21:26 +0900 [warn]: #0 define <match fluent.**> to capture fluentd logs in top level is deprecated. Use <label @FLUENT_LOG> instead
2020-02-17 11:21:26 +0900 [info]: #0 starting fluentd worker pid=204 ppid=34 worker=0
2020-02-17 11:21:26 +0900 [info]: #0 [input1] listening port port=24224 bind="0.0.0.0"
2020-02-17 11:21:26 +0900 [error]: #0 unexpected error error_class=Errno::EADDRINUSE error="Address in use - bind(2) for 0.0.0.0:24224"
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/2.5.0/socket.rb:201:in `bind'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/2.5.0/socket.rb:201:in `listen'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/gems/2.5.0/gems/fluentd-1.9.2/lib/fluent/plugin_helper/server.rb:355:in `server_create_tcp_socket'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/gems/2.5.0/gems/fluentd-1.9.2/lib/fluent/plugin_helper/server.rb:212:in `server_create_for_tcp_connection'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/gems/2.5.0/gems/fluentd-1.9.2/lib/fluent/plugin_helper/server.rb:92:in `server_create_connection'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/gems/2.5.0/gems/fluentd-1.9.2/lib/fluent/plugin/in_forward.rb:172:in `start'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/gems/2.5.0/gems/fluentd-1.9.2/lib/fluent/root_agent.rb:200:in `block in start'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/gems/2.5.0/gems/fluentd-1.9.2/lib/fluent/root_agent.rb:189:in `block (2 levels) in lifecycle'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/gems/2.5.0/gems/fluentd-1.9.2/lib/fluent/root_agent.rb:188:in `each'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/gems/2.5.0/gems/fluentd-1.9.2/lib/fluent/root_agent.rb:188:in `block in lifecycle'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/gems/2.5.0/gems/fluentd-1.9.2/lib/fluent/root_agent.rb:175:in `each'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/gems/2.5.0/gems/fluentd-1.9.2/lib/fluent/root_agent.rb:175:in `lifecycle'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/gems/2.5.0/gems/fluentd-1.9.2/lib/fluent/root_agent.rb:199:in `start'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/gems/2.5.0/gems/fluentd-1.9.2/lib/fluent/engine.rb:248:in `start'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/gems/2.5.0/gems/fluentd-1.9.2/lib/fluent/engine.rb:147:in `run'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/gems/2.5.0/gems/fluentd-1.9.2/lib/fluent/supervisor.rb:592:in `block in run_worker'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/gems/2.5.0/gems/fluentd-1.9.2/lib/fluent/supervisor.rb:823:in `main_process'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/gems/2.5.0/gems/fluentd-1.9.2/lib/fluent/supervisor.rb:586:in `run_worker'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/gems/2.5.0/gems/fluentd-1.9.2/lib/fluent/command/fluentd.rb:338:in `<top (required)>'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/lib/ruby/gems/2.5.0/gems/fluentd-1.9.2/bin/fluentd:8:in `<top (required)>'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/bin/fluentd:23:in `load'
  2020-02-17 11:21:26 +0900 [error]: #0 /usr/bin/fluentd:23:in `<main>'
2020-02-17 11:21:26 +0900 [error]: #0 unexpected error error_class=Errno::EADDRINUSE error="Address in use - bind(2) for 0.0.0.0:24224"
```

# エラー原因
[ここら辺](https://chiarab.hatenablog.com/entry/2018/11/05/000803)に近しい
psすると

```bash
/ # ps
PID   USER     TIME  COMMAND
    1 root      0:00 tini -- /bin/entrypoint.sh fluentd
    6 root      0:00 {fluentd} /usr/bin/ruby /usr/bin/fluentd -c /fluentd/etc/fluent.conf -p /fluentd/plugins
   20 root      0:00 /usr/bin/ruby -Eascii-8bit:ascii-8bit /usr/bin/fluentd -c /fluentd/etc/fluent.conf -p /fluentd/pl
   29 root      0:00 /bin/sh
  288 root      0:00 ps
```

すでにfluentdのプロセスがexecした時に起動されていてポート24224が使用されていたため

`unexpected error error_class=Errno::EADDRINUSE error="Address in use - bind(2) for 0.0.0.0:24224"`
のエラーがいっぱいでました。