title: The CentOS Error use "service td-agent status"
body: <p>I use td-agent in CentOS.</p>
  
  <p>When I typed "service td-agent start", I saw "Starting td-agent: [ OK ]".
  To check it, I typed "service td-agent status", but I saw "td-agent dead but pid file exists".
  I don't understand this result.
  Please tell me how to solve this.</p>
  
  <p>more
  when I typed "service td-agent start", I saw this messages. </p>
  
  <pre><code>Starting td-agent: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluentd-0.10.39/lib/fluent/supervisor.rb:30:in `initialize': Permission denied - /var/log/td-agent/td-agent.log (Errno::EACCES)
  from /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluentd-0.10.39/lib/fluent/supervisor.rb:30:in `open'
  from /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluentd-0.10.39/lib/fluent/supervisor.rb:30:in `init'
  from /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluentd-0.10.39/lib/fluent/supervisor.rb:79:in `start'
  from /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluentd-0.10.39/lib/fluent/command/fluentd.rb:141:in `&lt;top (required)&gt;'
  from /usr/lib64/fluent/ruby/lib/ruby/1.9.1/rubygems/custom_require.rb:55:in `require'
  from /usr/lib64/fluent/ruby/lib/ruby/1.9.1/rubygems/custom_require.rb:55:in `require'
  from /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluentd-0.10.39/bin/fluentd:6:in `&lt;top (required)&gt;'
  from /usr/lib64/fluent/ruby/bin/fluentd:23:in `load'
  from /usr/lib64/fluent/ruby/bin/fluentd:23:in `&lt;top (required)&gt;'
  from /usr/sbin/td-agent:7:in `load'
  from /usr/sbin/td-agent:7:in `&lt;main&gt;'
                                                         [FAILED]
  </code></pre>