title: How to let syslog workable in docker?
body: <p>My application will send out syslog local0 messages.
  When I move my application into docker, I found it is difficult to show the syslog.</p>
  
  <p>I've tried to run docker as --log-dirver as syslog or journald, both works strange, the /var/log/local0.log show console output of docker container instead of my application's syslog when I try to run this command inside container</p>
  
  <pre><code>logger -p local0.info -t a message
  </code></pre>
  
  <p>So, I try to install syslog-ng inside the docker container.
  The outside docker box is Arch Linux (kernel 4.14.8 + systemctl).
  The docker container is running as CentOS 6.  If I install syslog-ng inside the container and start it, it shows following message.</p>
  
  <pre><code># yum install -y syslog-ng  # this will install syslog-ng 3.2.5
  # /etc/init.d/syslog-ng start
  Plugin module not found in 'module-path'; module-path='/lib64/syslog-ng', module='afsql'
  Starting syslog-ng: Plugin module not found in 'module-path'; module-path='/lib64/syslog-ng', module='afsql'
  Error opening file for reading; filename='/proc/kmsg', error='Operation not permitted (1)'
  Error initializing source driver; source='s_sys', id='s_sys#0'
  Error initializing message pipeline;
  </code></pre>