title: Enable logging in docker mysql container
body: <p>I'm trying to get familiar with the docker ecosystem and tried to setup a mysql database container. With <code>docker-compose</code> this looks like:</p>
  
  <pre><code>version: '2'
  services:
    db:
      image: mysql:5.6.33@sha256:31ad2efd094a1336ef1f8efaf40b88a5019778e7d9b8a8579a4f95a6be88eaba
      volumes:
        - "./db/data:/var/lib/mysql"
        - "./db/log:/var/log/mysql"
        - "./db/conf:/etc/mysql/conf.d"
      restart: "yes"
      environment:
        MYSQL_ROOT_PASSWORD: rootpw
        MYSQL_DATABASE: db
        MYSQL_USER: db
        MYSQL_PASSWORD: dbpw
  </code></pre>
  
  <p>My conf directory contains one file:</p>
  
  <pre><code>[mysqld]
  log_error       =/var/log/mysql/mysql_error.log
  general_log_file=/var/log/mysql/mysql.log
  general_log     =1
  slow_query_log  =1
  slow_query_log_file=/var/log/mysql/mysql_slow.log
  long_query_time =2
  log_queries_not_using_indexes = 1
  </code></pre>
  
  <p>Unfortunately I don't get any log files that way. The setup itself is correct and the cnf file is used. After connecting to the container and creating the 3 files, <code>chown</code> them to <code>mysql</code> and restarting the container, the logging is working as expected.</p>
  
  <p>I'm pretty sure that this is a common scenario, and my current way to get it running seems really stupid. <strong>What is the correct way to do it?</strong> </p>
  
  <p>I could improve my approach by moving all this stuff in a Dockerfile, but this still seem strange to me.</p>