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Other Resources

Each customer VPC had secondary a CIDR block added to it. The utility subnets were created from this CIDR. We do not recommend adding a aws_vpc_ipv4_cidr_block_association resource to your Terraform configuration in order to manage this secondary CIDR block into your Terraform configuration. The reason behind this is that these secondary CIDRs were allocated using Amazon VPC IP Address Manager (IPAM) and customers do not have privileges to these IPAM resources.

References

• Cornell
  • 2023 Cornell AWS Direct Connect Architecture Migration
•  Terraform
  • The lifecycle Meta-Argument
• AWS
  • What is IPAM?