How to add new rule in existing Default Route Table in OCI using terraform

Question

I am trying to create a rule in the existing Default Route Table in OCI using terraform.

Basically I am trying to add a rule for internet gateway so I can access it using ssh. not sure but I am not able to access TCP till I am not adding rule in default table, new table not working for me..

But In OCI provider the option is available for only create new route table with rule instead of add rule in existing / default route table

I am just able to find below option for route table in oci provider, the rest belongs to DRG.

https://registry.terraform.io/providers/hashicorp/oci/latest/docs/resources/core_route_table

I am currently using below terraform code:

resource "oci_core_internet_gateway" "test_internet_gateway" {
    #Required
    compartment_id = var.compartment_ocid
    vcn_id = oci_core_vcn.test_vcn.id
}

resource "oci_core_route_table" "test_route_table" {
    #Required
    compartment_id = var.compartment_ocid
    vcn_id = oci_core_vcn.test_vcn.id
    #display_name = "Default Route Table for xyz"

    route_rules {
        #Required
        network_entity_id = oci_core_internet_gateway.test_internet_gateway.id
        #cidr_block = "0.0.0.0/0"
        destination = "0.0.0.0/0"
    }
}

Any way around or solution will helps !!!!

Answer 1

The displayed terraform code creates a Route Table and adds a route rule for 0.0.0.0/0. The missing piece is to map this Route Table to the subnet that is housing your VM.

Here are a couple of thoughts:

• You create the entire VCN and Compute VM thereby you manage your infrastructure completely. This also enables to create a subnet along side the VCN and map the route table to it.
• Use Terraform Resource discovery to generate TF code for existing infrastructure. Once the configuration files are generated, modify it to Map the Route Table to the subnet.

Lastly, please check this page to know about how to modify Default Resources. This could be your quick win.

Answer 2

UPDATE for OCI Provider
To answer your question, the version of OCI provider you are using (4.102.1) may not have the necessary functionality to create a route rules in a default route table in OCI. This could be due to a bug or limitation in the Terraform provider for OCI.

You can check the Terraform provider's documentation and GitHub issues to see if there are any known issues or workarounds for this problem. It's also possible that a newer version of the Terraform provider may have fixed this issue, so you may want to consider upgrading to the latest version if possible.

Alternatively, you may be able to add route rules in a default route table in OCI using other tools or methods, such as the OCI CLI or the OCI console.

Answer 3

Extended the answer of @bmuthuv

The below page have some clue that how we can Manage Default VCN Resources :

https://docs.oracle.com/en-us/iaas/Content/API/SDKDocs/terraformbestpractices_topic-vcndefaults.htm

I have replace resource oci_core_route_table with oci_core_default_route_table. The strange thing is resource "oci_core_default_route_table" is not present in registry provider document directly, you need to search "Managing Default VCN Resources" on oci register page as below:

https://registry.terraform.io/providers/oracle/oci/latest/docs

resource "oci_core_default_route_table" "this" {
  #SOURCE PAGE : https://www.tfwriter.com/oci/r/oci_core_default_route_table.html

  manage_default_resource_id = oci_core_subnet.test_subnet.route_table_id

  route_rules {
    #Required
    network_entity_id = oci_core_internet_gateway.test_internet_gateway.id
    destination = "0.0.0.0/0"
  }
}