Explaining Elastic IP Addresses in AWS

The aim of this page is to explain AWS Elastic IPs and their uses. I was under the incorrect impression that elasticity means that IPs are changing. Wrong! What's changing is a network resource using that IP, say in a crash a new resource can use the same address quickly. The amount of EIP in a VPC/region is pretty small actually - just 5. Having a case then I need to increase that limit to 7 when deploying resources. Some notes further down:

• Error Handling: Indeed, the AddressLimitExceeded error occurs when the maximum EIP limit is reached.
• Default Limit: AWS allows up to 5 EIPs per region by default.
• Static IP: A static IP does not change over time; useful for consistent access.
• Elastic IP (EIP): A static IP that can be reassigned to different instances dynamically.
• High Availability: EIPs mask instance failures by quickly remapping to another instance.
• Consistent DNS Setup: EIPs ensure DNS names point to the same IP, even if the instance changes.
• Load Balancing: EIPs help maintain high availability and reliability for services.
• Elasticity: Elasticity refers to the reassignment capability of an EIP, not changing the IP value.
• Usage with NAT Gateways: NAT gateways can use EIPs for outbound internet access.
• Checking EIP: Verify if a NAT gateway uses an EIP in the AWS VPC Console under NAT Gateway details.

LINKS

• https://aws.amazon.com/vpc/elastic-ip-addresses/
• https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/elastic-ip-addresses-eip.html
• https://aws.amazon.com/ec2/faqs/