备份
# cp /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.bak
修改
# vi /etc/yum.repos.d/CentOS-Base.repo
# CentOS-Base.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client. You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the
# remarked out baseurl= line instead.
#
# [base]
name=CentOS-$releasever - Base
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
baseurl=http://mirrors.163.com/centos/$releasever/os/$basearch/
gpgcheck=
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6 #released updates
[updates]
name=CentOS-$releasever - Updates
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
baseurl=http://mirrors.163.com/centos/$releasever/updates/$basearch/
gpgcheck=
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6 #additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
baseurl=http://mirrors.163.com/centos/$releasever/extras/$basearch/
gpgcheck=
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6 #additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus
baseurl=http://mirrors.163.com/centos/$releasever/centosplus/$basearch/
gpgcheck=
enabled=
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6 #contrib - packages by Centos Users
[contrib]
name=CentOS-$releasever - Contrib
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=contrib
baseurl=http://mirrors.163.com/centos/$releasever/contrib/$basearch/
gpgcheck=
enabled=
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
# yum clean all
# yum makecache #将服务器上的软件包信息缓存到本地,以提高搜索安装软件的速度
# yum install vim* #测试域名是否可用
开始更新系统：
# yum update
============================
注：CentOS使用yum update更新时不升级内核
cp /etc/yum.conf /etc/yum.confbak
方法一、修改yum的配置文件
# vi /etc/yum.conf 在[main]的最后添加 exclude=kernel*
方法二、直接在yum的命令后面加上如下的参数：
# yum --exclude=kernel* update