高手看一下怎么回事，关于yum

高手看一下怎么回事，关于yum
yum update的时候出现如下错误：fc8系统
Could not retrieve mirrorlist [url]http://mirrors.fedoraproject.org[/url] ... ora-8&arch=i386 error was
[Errno 14] HTTP Error 503: Service Temporarily Unavailable
Error: Cannot retrieve repository metadata (repomd.xml) for repository: fedora. Please verify its path and try again


1: # cd /etc/yum.repos.d/
2: # vi fedora.repo && #vi fedora-updates-testing.repo && #vi fedora-updates.repo
3: change all the #baseurl to baseurl and the mirrorlist to #mirrorlist
4: save and quit
5:yum check-update