title: Error: Failed to download metadata for repo 'appstream': Cannot prepare internal mirrorlist: No URLs in mirrorlist
body: <p>I am trying to download java using yum on centOs which I specified in Dockerfile.
  After pulling centOs image the run crushed and throw this error!?
  also to mention that my server instance is AWS EC2!</p>
  <pre><code>Step 2/9 : RUN yum install java -y
   ---&gt; Running in 39fc233aa965
  CentOS Linux 8 - AppStream                      184  B/s |  38  B     00:00
  Error: Failed to download metadata for repo 'appstream': Cannot prepare internal mirrorlist: No URLs in mirrorlist
  The command '/bin/sh -c yum install java -y' returned a non-zero code: 1
  </code></pre>