EIP

Source: src/AWS/EC2/EIP.ts

An Elastic IP address — a static, public IPv4 address allocated to your AWS account that you can attach to instances, network interfaces, or NAT gateways.

Allocating an EIP reserves the address; you then reference its allocationId from the resource that should use it (for example a public NatGateway). The address is released back to AWS when the resource is destroyed. The pool-related properties (publicIpv4Pool, networkBorderGroup, customerOwnedIpv4Pool) are immutable and replace the address when changed.

Allocating Elastic IPs

By default an Elastic IP is allocated for use within a VPC (domain: "vpc"), which is the only domain available to modern accounts.

const eip = yield* AWS.EC2.EIP("MyEip", {
  domain: "vpc",
  tags: { Name: "app-eip" },
});

This reserves a standard, Amazon-owned public IPv4 address scoped to your VPC; domain defaults to "vpc", so it can be omitted, and tags help you find the address in the console and on the bill.

Bring-Your-Own-IP and Address Pools

If you have onboarded an address range to AWS (BYOIP) or use Outposts, you can draw the address from a specific pool instead of Amazon’s general pool.

Allocate from a Public IPv4 (BYOIP) Pool

const eip = yield* AWS.EC2.EIP("ByoipEip", {
  publicIpv4Pool: "ipv4pool-ec2-0abcdef1234567890",
  networkBorderGroup: "us-east-1",
});

publicIpv4Pool selects an address from a pool you own rather than a random Amazon address, and networkBorderGroup restricts which zone group AWS advertises it from (useful for Local and Wavelength Zones).

Allocate from a Customer-Owned Pool (Outposts)

const eip = yield* AWS.EC2.EIP("CoIpEip", {
  customerOwnedIpv4Pool: "ipv4pool-coip-0abcdef1234567890",
});

customerOwnedIpv4Pool pulls a customer-owned IP (CoIP) from an Outposts-associated pool, for workloads that must use your own on-premises address space.

Using an Elastic IP

const eip = yield* AWS.EC2.EIP("NatEip", {});

const natGateway = yield* AWS.EC2.NatGateway("NatGateway", {
  subnetId: publicSubnet.subnetId,
  allocationId: eip.allocationId,
});

Downstream resources consume the reserved address through its allocationId; here the EIP becomes the fixed public IP of a NAT gateway.