yum check-update
Loading "installonlyn" plugin
Setting up repositories
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=5&arch=i386&repo=os error was
[Errno 4] IOError: <urlopen error (-3, 'Temporary failure in name resolution')>
Error: Cannot find a valid baseurl for repo: base
The issue has been fixed now. I have restarted named service on the server. We have disabled HyperVM due to recent exploits. We are still making our own control panel which will be replacement for hypervM.
Please check from your end and let us know if you need any further assistance.