Enable Connectivity Between Primary and Secondary Sites

To enable cross-region communication between Region A (Primary) and Region B (Secondary), you must configure Dynamic Routing Gateways (DRGs) in each region and connect them using a Remote Peering Connection (RPC). This setup forms the backbone for routing traffic across networks that support the stretched cluster.

Create DRG in Primary Site and Attach to VCNs in Primary Site

Create a DRG in Region A (Primary) and attach it to the following VCNs:

• VCN-Primary
• VCN-Mgmt-Active

This enables routing between VLANs across both VCNs within the primary region.

Create DRG in Secondary Site and Attach to VCN-Secondary

Similarly, in Region B (Secondary), create a DRG and attach it to: VCN-Secondary

This establishes routing within the secondary region in preparation for cross-region communication.

Note:

Do not attach the DRG to VCN-Mgmt-Failover at this stage. This step must be performed manually during a failover event, once management workloads are transitioned to Region B. At that time, routes pointing to VCN-Mgmt-Active will be replaced with routes to VCN-Mgmt-Failover. This will be covered in detail in the Failover section.

Establish Remote Peering Connection Between Regions

Once DRGs are created in both regions, establish a Remote Peering Connection (RPC) to enable secure, low-latency cross-region traffic flow.

The RPC can be initiated from either side; the result is symmetrical. Once established: Both Primary and Secondary DRGs must display routes to both local and remote CIDRs — i.e., 10.16.0.0/16 for Region A and 10.17.0.0/16 for Region B.