执行完yum -y install openstack-keystone httpd mod_wsgi python-openstackclient memcached python-memcached openstack-utils 命令后以为软件包全部安装好了，准备配置/etc/keystone/keystone.conf文件时发现没有此配置文件，意识到安装包没有安装成功。
重新执行yum -y install openstack-keystone httpd mod_wsgi python-openstackclient memcached python-memcached openstack-utils 命令后注意到报错：warning: /var/cache/yum/x86_64/7/epel/packages/crudini-0.7-1.el7.noarch.rpm:Public key for crudini-0.7-1.el7noarch.rpm.is not installed.
按照网上方法执行rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7命令依旧报错。
最终解决方法：
yum -y install openstack-keystone httpd mod_wsgi python-openstackclient memcached python-memcached openstack-utils --nogpgcheck