[Bug]: terraform apply is always changing the aws_route_table.

[Mahesh-008]

Terraform Core Version

Terraform v1.3.0

AWS Provider Version

aws v4.32.0

Affected Resource(s)

resource "aws_network_interface" "nat_network_interface" {
  subnet_id         = local.pri_sub_ids[0]
  source_dest_check = false
  security_groups   = [aws_security_group.nat-sg.id]

  tags = {
    Name = "${local.environment}-nat_instance_network_interface"
  }
}

resource "aws_route_table" "dev-vpc-private-rt" {
  vpc_id = aws_vpc.dev-vpc.id

  route {
    cidr_block = "0.0.0.0/0"
    #nat_gateway_id = aws_nat_gateway.dev-vpc-nat-gw.id
    network_interface_id = aws_network_interface.nat_network_interface.id
  }

  tags = {
    Name = "${local.environment}-Private-Route-Table"
  }
}

Expected Behavior

it should say no changes.

Actual Behavior

Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols:
  ~ update in-place

Terraform will perform the following actions:

  # aws_route_table.dev-vpc-private-rt will be updated in-place
  ~ resource "aws_route_table" "dev-vpc-private-rt" {
        id               = "rtb-0483528a4c0b5cf2f"
      ~ route            = [
          + {
              + carrier_gateway_id         = ""
              + cidr_block                 = "0.0.0.0/0"
              + core_network_arn           = ""
              + destination_prefix_list_id = ""
              + egress_only_gateway_id     = ""
              + gateway_id                 = ""
              + instance_id                = ""
              + ipv6_cidr_block            = ""
              + local_gateway_id           = ""
              + nat_gateway_id             = ""
              + network_interface_id       = "eni-019e42a1babbffe7e"
              + transit_gateway_id         = ""
              + vpc_endpoint_id            = ""
              + vpc_peering_connection_id  = ""
            },
          - {
              - carrier_gateway_id         = ""
              - cidr_block                 = "0.0.0.0/0"
              - core_network_arn           = ""
              - destination_prefix_list_id = ""
              - egress_only_gateway_id     = ""
              - gateway_id                 = ""
              - instance_id                = "i-066a7f52283db0dee"
              - ipv6_cidr_block            = ""
              - local_gateway_id           = ""
              - nat_gateway_id             = ""
              - network_interface_id       = "eni-019e42a1babbffe7e"
              - transit_gateway_id         = ""
              - vpc_endpoint_id            = ""
              - vpc_peering_connection_id  = ""
            },
        ]
        tags             = {
            "Name" = "DEV-VPC-Private-Route-Table"
        }
        # (5 unchanged attributes hidden)
    }

Plan: 0 to add, 1 to change, 0 to destroy.
aws_route_table.dev-vpc-private-rt: Modifying... [id=rtb-0483528a4c0b5cf2f]
aws_route_table.dev-vpc-private-rt: Modifications complete after 1s [id=rtb-0483528a4c0b5cf2f]

Apply complete! Resources: 0 added, 1 changed, 0 destroyed.

Relevant Error/Panic Output Snippet

Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols:
  ~ update in-place

Terraform will perform the following actions:

  # aws_route_table.dev-vpc-private-rt will be updated in-place
  ~ resource "aws_route_table" "dev-vpc-private-rt" {
        id               = "rtb-0483528a4c0b5cf2f"
      ~ route            = [
          + {
              + carrier_gateway_id         = ""
              + cidr_block                 = "0.0.0.0/0"
              + core_network_arn           = ""
              + destination_prefix_list_id = ""
              + egress_only_gateway_id     = ""
              + gateway_id                 = ""
              + instance_id                = ""
              + ipv6_cidr_block            = ""
              + local_gateway_id           = ""
              + nat_gateway_id             = ""
              + network_interface_id       = "eni-019e42a1babbffe7e"
              + transit_gateway_id         = ""
              + vpc_endpoint_id            = ""
              + vpc_peering_connection_id  = ""
            },
          - {
              - carrier_gateway_id         = ""
              - cidr_block                 = "0.0.0.0/0"
              - core_network_arn           = ""
              - destination_prefix_list_id = ""
              - egress_only_gateway_id     = ""
              - gateway_id                 = ""
              - instance_id                = "i-066a7f52283db0dee"
              - ipv6_cidr_block            = ""
              - local_gateway_id           = ""
              - nat_gateway_id             = ""
              - network_interface_id       = "eni-019e42a1babbffe7e"
              - transit_gateway_id         = ""
              - vpc_endpoint_id            = ""
              - vpc_peering_connection_id  = ""
            },
        ]
        tags             = {
            "Name" = "DEV-VPC-Private-Route-Table"
        }
        # (5 unchanged attributes hidden)
    }

Plan: 0 to add, 1 to change, 0 to destroy.
aws_route_table.dev-vpc-private-rt: Modifying... [id=rtb-0483528a4c0b5cf2f]
aws_route_table.dev-vpc-private-rt: Modifications complete after 1s [id=rtb-0483528a4c0b5cf2f]

Apply complete! Resources: 0 added, 1 changed, 0 destroyed.

Terraform Configuration Files

resource "aws_network_interface" "nat_network_interface" {
  subnet_id         = local.pri_sub_ids[0]
  source_dest_check = false
  security_groups   = [aws_security_group.nat-sg.id]

  tags = {
    Name = "${local.environment}-nat_instance_network_interface"
  }
}

resource "aws_route_table" "dev-vpc-private-rt" {
  vpc_id = aws_vpc.dev-vpc.id

  route {
    cidr_block = "0.0.0.0/0"
    #nat_gateway_id = aws_nat_gateway.dev-vpc-nat-gw.id
    network_interface_id = aws_network_interface.nat_network_interface.id
  }

  tags = {
    Name = "${local.environment}-Private-Route-Table"
  }
}

Steps to Reproduce

1. terraform init.
2. terraform plan (without making the any changes)

Debug Output

No response

Panic Output

No response

Important Factoids

No response

References

No response

Would you like to implement a fix?

No response

[github-actions]

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[ewbankkit]

Relates #1426.
Relates #14197.

[ewbankkit]

I'm going to close this issue as a duplicate of #1426 so that we can concentrate discussion in the linked issue.
Please add any additional comments there.

[github-actions]

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