阿里镜像地址

https://mirrors.aliyun.com/centos

改如下

cat > /etc/yum.repos.d/op.repo << EOF
[openstack]
name=openstack mirrors.aliyun.com
baseurl=https://mirrors.aliyun.com/centos/7/cloud/x86_64/openstack-train/
enabled=1
gpgcheck=0
EOF