SOA-C02 Reliability and Business Continuity Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  Configure the ECS service to run tasks in a single Availability Zone to reduce network latency.

  Why it's wrong here

  Concentrating all ECS tasks in a single Availability Zone creates a critical single point of failure: if that AZ experiences an outage, the entire production application becomes unavailable. ECS does not automatically migrate tasks across AZs, and the minimal latency benefit from single-AZ placement is far outweighed by the risk to service continuity and SLA. Thus, this configuration fails to meet the high-availability requirement.

• ✓

  Configure the ECS service to run tasks in at least two Availability Zones.

  Why this is correct

  Running ECS tasks in at least two Availability Zones is the fundamental high-availability pattern, because it ensures that if one AZ fails, the application continues serving from the remaining AZs. This placement strategy allows ECS to distribute tasks and maintains capacity during an AZ outage, preventing total loss of service. It directly addresses the need for fault tolerance and is the most appropriate action for a production workload.

• ✗

  Use the awsvpc network mode for the task definition.

  Why it's wrong here

  The awsvpc network mode assigns each task its own elastic network interface and private IP address, enabling features like security group per task and VPC networking, but it has no effect on where tasks are placed. Task placement in ECS is controlled by placement strategies, constraints, and the capacity provider, not by the network mode. Therefore, choosing awsvpc does not influence AZ-level availability and is irrelevant to the stated requirement.

• ✓

  Place the ECS service behind an Application Load Balancer.

  Why this is correct

  Placing the ECS service behind an Application Load Balancer is a correct supporting measure for high availability because the ALB distributes incoming traffic across healthy tasks, regardless of which AZ they run in. It continuously performs health checks and automatically stops sending requests to unhealthy tasks, rerouting traffic to the remaining targets. While an ALB does not by itself guarantee multi-AZ placement, it enables resilient traffic distribution and is an essential component of a highly available ECS architecture.

• ✗

  Use Fargate Spot capacity providers to reduce costs.

  Why it's wrong here

  Using Fargate Spot capacity providers reduces cost by running tasks on spare compute capacity, but those tasks can be interrupted at any time with only a two-minute warning. For a production application, unexpected interruptions would cause service disruption and violate the high-availability and reliability requirements. Cost savings do not justify the loss of resilience, so this option is not an appropriate solution.

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