title: Amazon EC2 instance can't update or use yum
body: <p>I am using Amazon's tutorial for <a href="http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/install-LAMP.html">installing a LAMP server</a>. The first several instructions involve using <code>yum</code>, but every single way I have tried to do it has resulted in the same message. I have found a few other recent questions about the same issue, none of which change anything on my setup.</p>
  
  <p>Here is the message:</p>
  
  <pre><code>Loaded plugins: priorities, update-motd, upgrade-helper
  Could not retrieve mirrorlist http://repo.us-east-1.amazonaws.com/latest/main/mirror.list error was
  12: Timeout on http://repo.us-east-1.amazonaws.com/latest/main/mirror.list: (28, 'Connection timed out after 10001 milliseconds')
  
  
  One of the configured repositories failed (Unknown),
  and yum doesn't have enough cached data to continue. At this point the only
  safe thing yum can do is fail. There are a few ways to work "fix" this:
  
   1. Contact the upstream for the repository and get them to fix the problem.
  
   2. Reconfigure the baseurl/etc. for the repository, to point to a working
      upstream. This is most often useful if you are using a newer
      distribution release than is supported by the repository (and the
      packages for the previous distribution release still work).
  
   3. Disable the repository, so yum won't use it by default. Yum will then
      just ignore the repository until you permanently enable it again or use
      --enablerepo for temporary usage:
  
          yum-config-manager --disable &lt;repoid&gt;
  
   4. Configure the failing repository to be skipped, if it is unavailable.
      Note that yum will try to contact the repo. when it runs most commands,
      so will have to try and fail each time (and thus. yum will be be much
      slower). If it is a very temporary problem though, this is often a nice
      compromise:
  
          yum-config-manager --save --setopt=&lt;repoid&gt;.skip_if_unavailable=true
  
   Cannot find a valid baseurl for repo: amzn-main/latest
  </code></pre>
  
  <p>I have done this same thing before without running into any problems, using the same tutorial, but it was several months ago. I don't know what has changed but my meager experience is keeping me from figuring it out.</p>