Elastic Ip

Assign an Elastic IP Address to an EC2 Instance

I recently installed a new Ec2 instance and setup the system for a web service. At some point, I rebooted the instance and noticed that I could not connect to the web service via the Public IP address assigned to it. Upon investigation I discovered that the public DNS address had changed hence service not accessible. To avoid this in future, Amazon has a built in feature to allow one to associate a static DNS IP address to an Instance so in the event of instance reboot, it does not get assigned a new DNS address but rather maintains the previously assigned address.