Attaching a VCN to a DRG

Attach a Virtual Cloud Network (VCN) to a Dynamic Routing Gateway (DRG).

A VCN can be attached to only one DRG at a time, but a DRG can be attached to many VCNs (see Networking Limits). The attachment is automatically created in the compartment that holds the VCN. The VCN and DRG don't need to be in the same compartment. You can optionally specify a display name for the attachment itself, otherwise a default is provided. You can decide to connect VCNs in the same region using a single DRG instead of local peering gateways (see Local VCN Peering Through an Upgraded DRG for more information about that use case). The default routing policies in a DRG allow traffic to be routed between all VCNs attached to it. If you're attaching a DRG to a VCN in another tenancy, you need to have IAM configurations in both tenancies as described in IAM Policies for Routing Between VCNs. You also need the OCID of the VCN.

When you create an attachment to a DRG (the DRG can be in another tenancy in the same OCI region), attachments on both the DRG and VCN are created and connected in one step. Attaching a DRG to a VCN results in a DrgAttachment object with its own OCID.

1. On the Virtual Cloud Networks list page, select the VCN that you want to work with. If you need help finding the list page or the VCN, see Listing VCNs.
2. On the details page, perform one of the following actions depending on the option that you see:
  
  Select the Gateways tab. Dynamic Routing Gateway Attachments is the first section on the page.
  
  Under Resources, select Dynamic Routing Gateways Attachments.
3. Select Create DRG Attachment.
  A VCN can only have one DRG attachment at a time.
4. Enter a friendly name for the DRG attachment. It doesn't have to be unique. Avoid entering confidential information.
5. In the DRG Location section, select Current Tenancy or Another tenancy depending on the location of the DRG you want to attach.
  
  If you select Current Tenancy, select a DRG from the list. If the DRG is in another compartment, select that compartment and then select the DRG.
  
  If you select Another tenancy, enter the OCID of the DRG.
6. (Optional) If you're setting up an advanced scenario for transit routing, you can associate a VCN route table with the DRG attachment (you can do this later):
  
  Select Advanced Options.
  
  In the Route Table Association section. Select the Select Exisiting option and then select a VCN route table that you want to associate with the VCN attachment to the DRG. If you select None, the default VCN route table is used.
7. (Optional) In the Tags section, add one or more tags. If you have permissions to create a resource, then you also have permissions to apply free-form tags to that resource. To apply a defined tag, you must have permissions to use the tag namespace. For more information about tagging, see Resource Tags. If you're not sure whether to apply tags, skip this option or ask an administrator. You can apply tags later.
8. Select Create DRG attachment.
The attachment is in the Attaching state for a short period.

When the attachment is ready, create a route rule in the subnet's route table directing subnet traffic to the DRG. See To route a subnet's traffic to a DRG.

From the Dynamic Routing Gateway Attachments list, you can also select the Actions menu (three dots) for the DRG attachment to view its details, manage its tags, and delete it.
Use the network drg-attachment create command and required parameters to attach a VCN to a DRG:
oci network drg-attachment create --drg-id drg-ocid --network-details [complex type] ...[OPTIONS]
For a complete list of parameters and values for CLI commands, see the CLI Command Reference.
Run the CreateDrgAttachment operation to create a DRG attachment to a VCN.

Oracle Cloud Infrastructure Documentation

Attaching a VCN to a DRG