aws_default_route_table

Provides a resource to manage a Default VPC Routing Table.

Each VPC created in AWS comes with a Default Route Table that can be managed, but not destroyed. This is an advanced resource, and has special caveats to be aware of when using it. Please read this document in its entirety before using this resource. It is recommened you do not use both aws_default_route_table to manage the default route table and use the aws_main_route_table_association, due to possible conflict in routes.

The aws_default_route_table behaves differently from normal resources, in that Terraform does not create this resource, but instead attempts to "adopt" it into management. We can do this because each VPC created has a Default Route Table that cannot be destroyed, and is created with a single route.

When Terraform first adopts the Default Route Table, it immediately removes all defined routes. It then proceeds to create any routes specified in the configuration. This step is required so that only the routes specified in the configuration present in the Default Route Table.

For more information about Route Tables, see the AWS Documentation on Route Tables.

For more information about managing normal Route Tables in Terraform, see our documentation on aws_route_table.

~> NOTE on Route Tables and Routes: Terraform currently provides both a standalone Route resource and a Route Table resource with routes defined in-line. At this time you cannot use a Route Table with in-line routes in conjunction with any Route resources. Doing so will cause a conflict of rule settings and will overwrite routes.

Example usage with tags:

resource "aws_default_route_table" "r" {
    default_route_table_id = "${aws_vpc.foo.default_route_table_id}"
    route {
        ...
    }

    tags {
        Name = "default table"
    }
}

Argument Reference

The following arguments are supported:

  • default_route_table_id - (Required) The ID of the Default Routing Table.
  • route - (Optional) A list of route objects. Their keys are documented below.
  • tags - (Optional) A mapping of tags to assign to the resource.
  • propagating_vgws - (Optional) A list of virtual gateways for propagation.

Each route supports the following:

  • cidr_block - (Required) The CIDR block of the route.
  • gateway_id - (Optional) The Internet Gateway ID.
  • nat_gateway_id - (Optional) The NAT Gateway ID.
  • instance_id - (Optional) The EC2 instance ID.
  • vpc_peering_connection_id - (Optional) The VPC Peering ID.
  • network_interface_id - (Optional) The ID of the elastic network interface (eni) to use.

Each route must contain either a gateway_id, an instance_id, a nat_gateway_id, a vpc_peering_connection_id or a network_interface_id. Note that the default route, mapping the VPC's CIDR block to "local", is created implicitly and cannot be specified.

Attributes Reference

The following attributes are exported:

  • id - The ID of the routing table