fluent-plugin-mackerelでhttpdのステータスコードを送信 ref: http://qiita.com/okisanjp/items/9da6220e2230b06eb76a

file0.txt

# /usr/lib64/fluent/ruby/bin/fluent-gem install fluent-plugin-datacounter

file1.txt

# /usr/lib64/fluent/ruby/bin/fluent-gem install fluent-plugin-mackerel

file2.txt

<source>
  type tail
  format apache2
  path /var/log/httpd/access.log
  pos_file /var/log/td-agent/access.log.pos
  tag data.httpd.accesslog
</source>
<match data.httpd.accesslog>
  type datacounter
  count_interval 1m
  count_key code
  tag mackerel.httpd.accesslog
  outcast_unmatched yes
  pattern1 2xx ^2\d\d$
  pattern2 3xx ^3\d\d$
  pattern3 404 ^404$
  pattern4 4xx ^4\d\d$
  pattern5 5xx ^5\d\d$
</match>

<match mackerel.httpd.accesslog>
  type mackerel
  api_key YOUR_API_KEY
  service YOUR_SERVICE_NAME
  metrics_name http_status.${out_key}
  out_keys data.httpd.accesslog_2xx_count,data.httpd.accesslog_3xx_count,data.httpd.accesslog_404_count,data.httpd.accesslog_4xx_count,data.httpd.accesslog_5xx_count
</match>

file3.txt

# service td-agent reload