EIPs are dynamically re-mappable static public IP addresses that make it easier to manage EC2 instances. Each EIP can be re-assigned to a different EC2 instance when needed. You control the EIP address until you choose to explicitly release it. An Elastic IP is associated with your account and not a particular EC2 instance. Since, public IP addresses are a scarce resource you are limited to 5. If you need more EIPs then you have to apply for your limit to be raised. If you have a large deployment then an elastic load balancer (ELB part of AWS) is placed in front of all the instances thereby consuming one EIP only.

You will be charged for all EIPs not associated with running EC2 instances. It is charged at 0.01$/hour for each unassociated EIP.

Following are the steps to create an Elastic IP: 

1. From the EC2 dashboard, click on Elastic IPs in the navigation pane and then on Allocate New Address. Click on the Allocate button: 

2. You should see the following message that the new address request has been successfully processed. This step allocates a new EIP associated with your account:

Following are the steps to create an Associate IP:

1. The next step is to associate the EIP to an instance. Click on the Associate Address menu item:

4. Select the A1ElectronicsEcommerce instance from the drop-down list:

5. Click on the Associate button:

6. You should see the following message confirming that the associate address request was successfully completed:

7. From the EC2 dashboard, click on Instances in the navigation pane then on A1ElectronicsEcommerce to view the details. The EIP is assigned to the instance. Use ping to test the instance either by the EIP address 34.215.190.229 or by the domain name ec2-34-215-190-229.us-west-2.compute.amazonaws.com from the terminal: