This image shows how you can deploy Oracle REST Data Service with high availability on Oracle Cloud Infrastructure. It shows an Oracle Cloud Region containing a single availability domain which itself contains two fault domains, labeled Fault Domain 1 and Fault Domain 2. Both fault domains are within a Virtual Cloud Network (VCN), labeled VCN Subnet A. This subnet itself contains these three public regional subnets:

• Public Regional Subnet A, which contains the load balancer tier. Each fault domain contains a load balancer; fault domain 1 is an active load balancer while fault domain 2 has the standby load balancer. Access is restricted by a security list and a network security group (NSG).
• Public Regional Subnet B, which contains the Oracle REST Data Services tier and extends outside the availability domain, although still within the VCN. The image shows one ORDS instance in each fault domain and a third instance outside of the domain but within the VCN. Access is restricted by a security list and an NSG in both fault domains; however, the ORDS instance outside the fault domains is not.
• Public Regional Subnet C, which contains the Database tier. It contains a single active database, exclusively within fault domain 1. Access is restricted by a security list and an NSG.

The end user accesses Public Regional Subnet A bidirectionally through an Internet Gateway and on to the load balancer in Fault Domain 1. The standby load balancer in Fault Domain 2 can be accessed if necessary. The load balancer distributes traffic to an ORDS instance in Public Regional Subnet B (the ORDS tier). Instances in both fault domains communicate bidirectionally with the database in Public Regional Subnet C.

The database backs up data to object storage, which is within the region but outside the availability domain and the VCN. It also communicates bidirectionally, via DataGuard Sync, with a database in the load balancer tier within a private regional subnet in Oracle Cloud Region 2.