此方法用于 shell 脚本中获取真实 IP 以及主机名
hostname=$(curl http://100.100.100.200/2016-01-01/meta-data/hostname)
ipaddress=$(curl http://100.100.100.200/2016-01-01/meta-data/private-ipv4)
参考文档: https://cloudinit.readthedocs.io/en/latest/reference/datasources/aliyun.html#alibaba-cloud-aliyun