Create a New Elastic IP (EIP)
Objective
To set up two Elastic IPs for the front-ends of your production Deployment.
Table of Contents
Prerequisites
Amazon Elastic IPs are EC2 region-specific. You cannot use an EIP that you created in EC2-US for an instance in a different region like EC2-EU. This tutorial assumes you are creating an EIP for use in a specific EC2-US region.
Overview
Amazon's Elastic IP (EIP) addresses allow you to assign an IP address to an instance of your choice, which replaces the need for normal dynamic IP addressing in the cloud. Elastic IPs are static addresses, but are dynamically remappable IP addresses within the cloud, making it easier to manage servers and make global changes compared to static IPs on traditional hosting solutions. It's a way of ensuring that you don't 'inherit' traffic from other's servers on EC2, because you're using an IP that's specifically reserved for your usage only, as long as you keep that EIP. EIPs allow you to mask instance or Availability Zone failures by rapidly remapping your public IP addresses to any instance in your account. See Elastic IP (EIP) for more information.
By default, an account can have a maximum of five Elastic IPs. Amazon charges you $0.01/hr for each unused EIP that you reserve because you're essentially taking away another public IP address from Amazon's IP pool that they can no longer provision to another EC2 instance. If you want to create more than 5 EIPs, you can submit a request to Amazon at Request to Increase Elastic IP Address Limit.
For a conceptual diagram and example of how you can use EIPs to update a site, see our blog post DNS, Elastic IPs (EIP) and how things fit together when upgrading a server or read the section on on Designing Failover Architectures on EC2.
Steps
Creating an Elastic IP
- Go to Clouds > your AWS region
- Click EC2 Elastic IPs.
- Click New.
In a couple of minutes a new Elastic IP address will be added to your account. Refresh your window and you should see the IP address that was just created.
- Click on the Elastic IP's default nickname, change it to fe1 and click ok.
- Create another EIP and name it fe2. Write down the IP addresses for the front-end servers because you will need to list them in the next step.
Congratulations! You now have two Elastic IPs that you can associate to an EC2 instance. You can either attach an Elastic IP to instance at boot time or to a running instance. See Elastic IP (EIP) to learn more about the best practices on using EIPs.
Assign Elastic IP at Launch Time
When you launch a server, you have the choice of assigning an Elastic IP at launch time. You will need to select these EIPs when you launch a server in one of the later Application Server Setup tutorials.
WARNING! Be careful NOT not to steal an EIP from an existing server.
Assign Elastic IP to an Operational Server
Use the Edit action button to assign/reassign an EIP to a running server.
Note: You will only see the edit button next to a running server.
See also
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