首先编辑文件 centos-Base.repo
vi /etc/yum.repos.d/centos-Base.repo
删除文件内默认的全部代码，替换为 下面的代码
# 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-$releasever – Base – mirrors.aliyun.comfailovermethod=prioritybaseurl=http://mirrors.aliyun.com/centos/$releasever/os/$basearch/ http://mirrors.aliyuncs.com/centos/$releasever/os/$basearch/ http://mirrors.cloud.aliyuncs.com/centos/$releasever/os/$basearch/gpgcheck=1gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-centos-7 #released updates [updates]name=centos-$releasever – Updates – mirrors.aliyun.comfailovermethod=prioritybaseurl=http://mirrors.aliyun.com/centos/$releasever/updates/$basearch/ http://mirrors.aliyuncs.com/centos/$releasever/updates/$basearch/ http://mirrors.cloud.aliyuncs.com/centos/$releasever/updates/$basearch/gpgcheck=1gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-centos-7 #additional packages that may be useful[extras]name=centos-$releasever – Extras – mirrors.aliyun.comfailovermethod=prioritybaseurl=http://mirrors.aliyun.com/centos/$releasever/extras/$basearch/ http://mirrors.aliyuncs.com/centos/$releasever/extras/$basearch/ http://mirrors.cloud.aliyuncs.com/centos/$releasever/extras/$basearch/gpgcheck=1gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-centos-7 #additional packages that extend functionality of existing packages[centosplus]name=centos-$releasever – Plus – mirrors.aliyun.comfailovermethod=prioritybaseurl=http://mirrors.aliyun.com/centos/$releasever/centosplus/$basearch/ http://mirrors.aliyuncs.com/centos/$releasever/centosplus/$basearch/ http://mirrors.cloud.aliyuncs.com/centos/$releasever/centosplus/$basearch/gpgcheck=1enabled=0gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-centos-7 #contrib – packages by centos Users[contrib]name=centos-$releasever – Contrib – mirrors.aliyun.comfailovermethod=prioritybaseurl=http://mirrors.aliyun.com/centos/$releasever/contrib/$basearch/ http://mirrors.aliyuncs.com/centos/$releasever/contrib/$basearch/ http://mirrors.cloud.aliyuncs.com/centos/$releasever/contrib/$basearch/gpgcheck=1enabled=0gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-centos-7
最后保存后，清理并重新加载yum源
yum clean all && yum makecache
最后再次尝试升级
yum update -y
