vim /etc/yum.repos.d/mongodb-org-4.0.repo
[mongodb-org] name=MongoDB Repository baseurl=http://mirrors.aliyun.com/mongodb/yum/redhat/7Server/mongodb-org/4.0/x86_64/ gpgcheck=0 enabled=1 gpgkey=https://www.mongodb.org/static/pgp/server-4.0.asc
yum clean all
yum repolist
yum install mongodb-org -y