备份本地yum源：

mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo_bak;

下载阿里云yum源

curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo;
或
 curl -o /etc/yum.repos.d/CentOS-Bash.repo  https://mirrors.aliyun.com/repo/Centos-vault-8.5.2111.repo;

清理缓存

yum clean all

更新cache

yum makecache;

查看更新

yum -y update;

关闭selinux

sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config
reboot (重启方可永久生效)

配置时间同步

yum install -y ntp ntpdate
ntpdate cn.pool.ntp.org

配置时间同步定时任务

crontab -e
* */1 * * * /usr/sbin/ntpdate cn.pool.ntp.org （每一个小时，同步一次）
systemctl restart crond （重启下定时认为进程）

安装依赖

yum install -y  wget  net-tools  nfs-utils  lrzsz  gcc gcc-c++ make cmake libxml2-devel openssl-devel curl curl-devel unzip sudo ntp libaio-devel wget vim ncurses-devel autoconf automake zlib-devel python-devel epel-release openssh-server socat ipvsadm conntrack yum-utils