[Enhancement]: IPAM subnet reservations

[drewmullen]

Description

AWS Announced VPC Subnets can get their CIDR from AWS IPAM IP Reservations. I'm not 100% what the implementation will look like but will update this issue as the service features become available publicly.

Based on the blog I believe the following changes need to be made

1. aws_vpc_ipam_pool needs to be able to set resource planning to a vpc
2. aws_subnet needs to specify the cidr block is from an ipam pool id, ip netmask

These values are

• CreateSubnet: Ipv4IpamPoolId, Ipv4NetmaskLength, Ipv6IpamPoolId, Ipv6NetmaskLength
• CreateIpamPool - SourceResource which is a new nested type: https://github.com/aws/aws-sdk-go-v2/blob/main/service/ec2/types/types.go#L7919

Affected Resource(s) and/or Data Source(s)

• aws_vpc_ipam_pool
• aws_subnet

Potential Terraform Configuration

### ipam pool

resource aws_vpc_ipam_pool main {
  source_resource {

	resource_id = <>

	resource_owner = <> # account owner id

	resource_region = <>

	// The source resource type.
	ResourceType = "vpc" # https://github.com/aws/aws-sdk-go-v2/blob/main/service/ec2/types/enums.go#L4776

  }
}

### vpc subnet

```hcl
resource aws_subnet main {
  ipv4_ipam_pool_id = ""
  ipv6_ipam_pool_id = ""

  ipv4_netmask_length = #
  ipv6_netmask_length = #
}

### References

_No response_

### Would you like to implement a fix?

None

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[drewmullen]

To confirm design I need to try this out with CLI commands. The docs arent updated yet because #reinvent

[laminarcode]

API documentation now available: https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_CreateSubnet.html
Kindly implement the following attributes in terraform:

• Ipv4IpamPoolId
• Ipv4NetmaskLength
• Ipv6IpamPoolId
• Ipv6NetmaskLength

[OJFord]

Have you started on this @drewmullen?

I'm not certain I'll be able to, but keen to use this & may have a look at what it would take at least.

[fam0xf]

Any update on this feature?

[mhuber-avst]

I also am anxiously awaiting this feature. When can we expect this to be implemented?

[drewmullen]

@mhuber-avst
AFAIK no one has picked up or been assigned to the FR. I dont have time right now to pick it up, sadly. I’m not in the provider team - I just do this work for fun when I have time

[yves-vogl]

I'd like to help on this issue. @drewmullen please come back to me whenever you have time and feel like working on the issue. I'd be happy to learn from you to be able to assist in the future.