[BUG] Cannot replace Virtual Private Gateway route with Transit Gateway route in aws_route resource

[snovikov]

When trying to replace existing route pointing to VGW (Virtual Private Gateway) with TGW (Transit Gateway) error is thrown.

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Terraform Version

$ terraform version
Terraform v0.12.24
+ provider.aws v2.61.0

Affected Resource(s)

• aws_route

Terraform Configuration Files

resource "aws_route" "this" {
  for_each = {
    for route in local.routes_in_tables : "${route.table_id}.${route.dest_cidr_block}" => route...
  }

  provider = aws.satellite

  destination_cidr_block = each.value[0].dest_cidr_block
  transit_gateway_id     = local.transit_gateway_id
  route_table_id         = each.value[0].table_id

  depends_on = [aws_ec2_transit_gateway_vpc_attachment.this]
}

Debug Output

When run apply:

An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
  ~ update in-place

Terraform will perform the following actions:

  # aws_route.this["rtb-aaaabbbb.10.10.10.0/24"] will be updated in-place
  ~ resource "aws_route" "this" {
        destination_cidr_block = "10.10.10.0/24"
        gateway_id             = "vgw-0aaaabbbbccccdddd"
        id                     = "r-rtb-aaaabbbb1111222233"
        origin                 = "CreateRoute"
        route_table_id         = "rtb-aaaabbbb"
        state                  = "active"
      + transit_gateway_id     = "tgw-0aaaabbbbccccdddd"

        timeouts {}
    }

Plan: 0 to add, 1 to change, 0 to destroy.

Panic Output

Expected Behavior

VGW route is replaced with TGW route

Actual Behavior

Error message:

Error: more than 1 target specified. Only 1 of gateway_id, egress_only_gateway_id, nat_gateway_id, instance_id, network_interface_id or vpc_peering_connection_id is allowed.

Steps to Reproduce

1. terraform import 'aws_route.this["rtb-aaaabbbb.10.10.10.0/24"]' rtb-aaaabbbb_10.10.10.0/24
2. terraform apply

Important Factoids

References

Similar to

• [BUG] aws_route with conditional target to use nat_gateway_id or transit_gateway_id #13079

[ewbankkit]

Similar:

• aws_route Error: more than 1 targe specified if you change the destination type #684
• Can not change target type on existing aws_route #12631
• [BUG] aws_route with conditional target to use nat_gateway_id or transit_gateway_id #13079

[ghost]

This has been released in version 3.34.0 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!