출처:http://tech-queries.blogspot.com/2011/06/how-to-get-public-ip-for-amazon-ec2.html
To obtain the internal IP address:
curl http://169.254.169.254/latest/meta-data/local-ipv4
To obtain the public IP address:
curl http://169.254.169.254/latest/meta-data/public-ipv4
