title: resolv.conf seems to always be wrong when building Docker container
body: <p>I am attempting to write <code>Dockerfile</code> instructions to use <code>yum</code> and install a few packages. When I run my build command, I will always get an error...</p>
  <pre class="lang-sh prettyprint-override"><code>(28, 'Resolving timed out after 5000 milliseconds')
  </code></pre>
  <p>... due to the lack of network access. I have compared my host and container <code>/etc/resolv.conf</code>, and noticed they were different.</p>
  <p>Example (Host)</p>
  <pre><code># Generated by expressvpn
  search expressvpn
  nameserver 10.53.0.1
  </code></pre>
  <p>Example (Container)</p>
  <pre><code>search expressvpn
  nameserver 10.1.2.3
  nameserver 8.8.8.8
  </code></pre>
  <p>I attempted copying the host <code>/etc/resolv.conf</code> and overwriting the container <code>/etc/resolv.conf</code> as follows</p>
  <pre class="lang-sh prettyprint-override"><code>$ echo &quot;# Generated by expressvpn
  &gt; search expressvpn
  &gt; nameserver 10.53.0.1&quot; &gt; &quot;/etc/resolv.conf&quot;
  </code></pre>
  <p>Then immediately gained network access again and was able to use <code>yum</code>. However, if I try reading the <code>Dockerfile</code> with a build command, it does not seem to work anymore. How do I make docker use the host <code>resolv.conf</code> on build or resolve this issue correctly? It seemed to not have an issue with my VPN before. Is that the issue now?</p>