1Z0-1104-25 Question 73
Single answerYour organization is deploying a multi-tier application in Oracle Cloud Infrastructure (OCI) across two Availability Domains within the same region. You need to ensure uninterrupted service in the event one Availability Domain goes offline, while adhering to best security practices. Which approach should you use for the Load Balancer configuration to achieve high availability and minimal downtime?
- A
Create a public Load Balancer with subnets in only one Availability Domain, relying on compute instances spread across both Availability Domains for redundancy.
- B
Deploy a public Load Balancer with two subnets, one in each Availability Domain, configure a single backend set spanning both domains, and enable health checks for failover.
- C
Use a private internal Load Balancer across multiple subnets, ensuring that all frontend internet traffic is forced through a separate NAT gateway.
- D
Depend solely on auto-scaling of compute instances in each Availability Domain and avoid configuring a centralized Load Balancer.
Show answer and explanation
Correct answer: B
Explanation
For high availability in OCI, the recommended practice is to deploy a single Load Balancer across multiple subnets in different Availability Domains. This configuration ensures continuous service even if one Availability Domain goes offline, because the Load Balancer� health checks reroute traffic to healthy backends in the other domain. Refer to OCI documentation (docs.oracle.com/en-us/iaas/Content/Balance/Concepts/balanceoverview.htm) for detailed guidance on setting up subnets, backend sets, and health checks for multi-AD deployments.
- A. Incorrect.
Incorrect. Placing the Load Balancer in only one Availability Domain creates a single point of failure. Although the compute instances are in both domains, if the AD hosting the Load Balancer fails, traffic cannot be served.
- B. Correct.
Correct. Best practice is to deploy a Load Balancer with subnets in separate Availability Domains for high availability. Spanning multiple ADs allows traffic rerouting through health checks if one domain experiences an outage.
- C. Incorrect.
Incorrect. While private Load Balancers have valid use cases, forcing all external traffic through a NAT gateway for high availability is not typically recommended for public-facing applications. You also lose the advantages of a public Load Balancer supporting direct internet traffic.
- D. Incorrect.
Incorrect. Auto-scaling helps handle load changes but does not protect against the Load Balancer point of failure. A dedicated Load Balancer is needed for true high availability.