CloudFormation deleting nlb did not release public IP

Hi There

This is happening because the EIP is associated with the managed network interface of the load balancer. It takes some time for the deleted NLB to release the network interface. You cant delete the EIP until the network interface is gone, and unfortunately CloudFormation doesnt have any knowledge of this.

You can do any of the following:

• Dont use an Elastic IP and just let AWS assign a public IP to the NLB. Example:

  loadBalancer:
    Type: 'AWS::ElasticLoadBalancingV2::LoadBalancer'
    Properties:
      Type: network
      IpAddressType: ipv4
      Scheme: internet-facing
      Subnets: !Ref Subnets

• Perform a delete-stack operation again, after verifying that any network interfaces(belonging to network load balancer) are deleted by elbv2 service itself and association id is removed from EIP.
• Use DeletionPolicy/UpdateReplacePolicy attributes with AWS::EC2::EIP resource and set value to Retain to achieve single step stack deletion. Note that you will still need to delete the EIP manually.