title: Does .ebextensions or requirements.txt run first in Elastic Beanstalk
body: <p>the <code>.config</code> file in <code>.ebextensions</code> or <code>requirements.txt</code> runs first?</p>
  
  <p>I want to install <code>psycopg2</code> present in <code>requirements.txt</code> for that, I need to install <code>postgresql-devel</code>, <code>python-devel</code> packages installed first. </p>
  
  <p>When I create my config settings like</p>
  
  <p><strong>requirements.txt</strong> </p>
  
  <pre><code>psycopg2
  </code></pre>
  
  <p><strong>.ebextensions/mysite.config</strong></p>
  
  <pre><code>packages:
    yum:
      gcc: []
      python-devel: []
      postgresql-devel: []
  </code></pre>
  
  <ol>
  <li><p>From the logs, I observed that, requirements.txt executed first, thus raising errors as prerequisites are not installed.</p></li>
  <li><p>yum is raising <code>postgresql-devel</code> is not found in packages.</p></li>
  </ol>
  
  <p>How do I fix these? Where I am going wrong?</p>