title: MySQLi not found dockerized php
body: <p>I'm trying to dockerize my website. I've got Nginx and PHP up and running and it's working find except I can't connect to a db. When the page is loaded I get the error:</p>
  
  <pre><code>Fatal error: Uncaught Error: Class 'MySQLi' not found in /private/conn.php:8 Stack trace: #0 /public_html/index.php(2): require() #1 {main} thrown in /private/conn.php on line 8
  </code></pre>
  
  <p>My connection line on line 8 is:</p>
  
  <pre><code>$db = new mysqli("$host", "$user", "$pass", "$db", "$port");
  </code></pre>
  
  <p>Now this used to work fine on my old set up but since moving to a new one and installing php7.1.5 I can't get it running. Now, I haven't used the mysqlnd so this may be a misunderstanding on my part but the mysqlnd includes the mysqli driver.</p>
  
  <p>Output of phpinfo:
  <a href="https://i.stack.imgur.com/SwS4S.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/SwS4S.jpg" alt="config"></a>
  <a href="https://i.stack.imgur.com/RmAl0.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/RmAl0.jpg" alt="mysqlnd"></a></p>
  
  <p>How can I get this running? Or should I be using a different driver now?</p>