For Gateway Load Balancer, enable_cross_zone_load_balancing is always false, regardless of what value is chosen

[mabdelghany]

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Terraform CLI and Terraform AWS Provider Version

Terraform CLI: v0.13.5
AWS Provider Version: v3.15.0_x5

Affected Resource(s)

• aws_lb

Terraform Configuration Files

resource "aws_lb" "gwlb" {
  name                             = "${var.prefix}-gateway-lb"
  load_balancer_type               = "gateway"
  subnets                          = var.subnet_ids
  enable_cross_zone_load_balancing = true
}

Deploying this using terraform apply works fine. When you check the gateway load balancer in the console, you will see that the cross zone load balancing is disabled.

Debug Output

I ran another terraform plan after my successful deployment and got this

resource "aws_lb" "gwlb" {
        arn                              = "arn:aws:elasticloadbalancing:us-east-1:xxxxxxxxxxxx:loadbalancer/gwy/xxxxxxxxxxxx-gateway-lb/xxxxxxxxxxxx"
        arn_suffix                       = "gwy/xxxxxxxxxxxx-gateway-lb/xxxxxxxxxxxx"
        drop_invalid_header_fields       = false
      ~ enable_cross_zone_load_balancing = false -> true
        enable_deletion_protection       = false
        enable_http2                     = true
        id                               = "arn:aws:elasticloadbalancing:us-east-1:xxxxxxxxxxxx:loadbalancer/gwy/xxxxxxxxxxxx-gateway-lb/xxxxxxxxxxxx"
        idle_timeout                     = 60
        internal                         = false
        load_balancer_type               = "gateway"
        name                             = "xxxxxxxxxxxx-gateway-lb"
        security_groups                  = []
        subnets                          = [
            "subnet-xxxxxxxxxxxx",
            "subnet-xxxxxxxxxxxx",
        ]
        tags                             = {
            "CreatedBy"   = "xxxxxxxxxxxx"
            "Environment" = "ProdNet"
            "Name"        = "xxxxxxxxxxxx-gateway-lb"
        }
        vpc_id                           = "vpc-xxxxxxxxxxxx"

        access_logs {
            enabled = false
        }

        subnet_mapping {
            subnet_id = "subnet-xxxxxxxxxxxx"
        }
        subnet_mapping {
            subnet_id = "subnet-xxxxxxxxxxxx"
        }
    }

Expected Behavior

The cross zone load balancing should be enabled

Actual Behavior

The cross zone load balancing is always disabled

Steps to Reproduce

1. terraform apply
2. terraform plan

[bflad]

Fix submitted: #16314

[bflad]

The fix for this has been merged and will release with version 3.17.0 of the Terraform AWS Provider, middle of next week. 👍

[ghost]

This has been released in version 3.17.0 of the Terraform AWS provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template for triage. Thanks!

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!