1Z0-1104-25 Question 78
Single answerA retail company has deployed their e-commerce platform on Oracle Cloud Infrastructure (OCI), distributing multiple compute instances across two Availability Domains in a single region. They created a load balancer in a single subnet within the same AD as the compute instances. During a recent AD outage, the application went offline. As an OCI Security Professional, you must adjust the architecture to ensure high availability even if one AD goes down. Which strategy should you implement to achieve this goal?
- A
Create a single load balancer with subnets in multiple Availability Domains and place all compute instances in a single backend set
- B
Configure multiple load balancers, each in its own AD, and manually update DNS records during AD outages
- C
Add a reserved public IP address to each compute instance and configure a third-party load balancing service
- D
Create path route rules that send traffic to the second AD only when the first AD fails
Show answer and explanation
Correct answer: A
Explanation
For high availability on Oracle Cloud Infrastructure, place your load balancer in at least two subnets, each in a different Availability Domain (or fault domain if only one AD is available). This ensures uninterrupted service in case one AD fails. Oracle documentation recommends creating a regional load balancer design for mission-critical applications. Refer to the OCI Load Balancer documentation for details on subnet placement, health checks, and best practices.
- A. Correct.
Option 1: Correct. Using a single OCI load balancer across two subnets in different Availability Domains is a best practice for high availability. This ensures that if one AD goes down, the load balancer will continue serving traffic from the healthy AD while using the same public IP and backend set.
- B. Incorrect.
Option 2: Incorrect. Deploying multiple load balancers and managing manual DNS changes can cause additional downtime and complexity. It is not the recommended approach for real-time high availability in OCI.
- C. Incorrect.
Option 3: Incorrect. Assigning public IPs to every compute instance and relying on an external service bypasses many OCI integrated features for automatic failover and health checks. This approach can introduce security and management overhead.
- D. Incorrect.
Option 4: Incorrect. Path-based routing rules determine how traffic is routed based on URI paths, not AD availability. Simply using path routing does not guarantee that traffic fails over if an AD becomes unavailable.