CentOS5.4更新到5.5
1、先修改更新源为国内的更新源
# cd /etc/yum.repos.d
# mv CentOS-Base.repo CentOS-Base.repo.save
# vi /etc/yum.repos.d/Centos-Base.repo
[base]
name=CentOS-$releasever - Base
#mirrorlist=http://centos.ustc.edu.cn/?release=$releasever&arch=$basearch&repo=os
baseurl=http://centos.ustc.edu.cn/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-centos4

#released updates
[update]
name=CentOS-$releasever - Updates
#mirrorlist=http://centos.ustc.edu.cn/?release=$releasever&arch=$basearch&repo=updates
baseurl=http://centos.ustc.edu.cn/centos/$releasever/updates/$basearch/
gpgcheck=1
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-centos4

#packages used/produced in the build but not released
[addons]
name=CentOS-$releasever - Addons
#mirrorlist=http://centos.ustc.edu.cn/?release=$releasever&arch=$basearch&repo=addons
baseurl=http://centos.ustc.edu.cn/centos/$releasever/addons/$basearch/
gpgcheck=1
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-centos4

#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
#mirrorlist=http://centos.ustc.edu.cn/?release=$releasever&arch=$basearch&repo=extras
baseurl=http://centos.ustc.edu.cn/centos/$releasever/extras/$basearch/
gpgcheck=1
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-centos4

#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
#mirrorlist=http://centos.ustc.edu.cn/?release=$releasever&arch=$basearch&repo=centosplus
baseurl=http://centos.ustc.edu.cn/centos/$releasever/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-centos4

#contrib - packages by Centos Users
[contrib]
name=CentOS-$releasever - Contrib
#mirrorlist=http://centos.ustc.edu.cn/?release=$releasever&arch=$basearch&repo=contrib
baseurl=http://centos.ustc.edu.cn/centos/$releasever/contrib/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-centos4
2、清理残留文件然后更新标准库,再升级
# yum clean all
# yum update glibc\*
# yum update yum\* rpm\* python\*
# yum clean all
# yum update
# reboot