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Difficulty: MediumPerformance and Scalability Optimization

A digital publishing company is launching a breaking news notification system. When a major global news event is broadcast, the system will send push notifications that will immediately drive a surge of over 80,00080,000 concurrent readers to a web portal within three minutes. The portal runs on Amazon EC2 instances within an Auto Scaling group behind an Application Load Balancer (ALB). The database backend is an Amazon Aurora PostgreSQL cluster with one primary writer and one replica. The portal's traffic is highly read-intensive, requiring dynamic read scaling of the database. Which actions should a Solutions Architect recommend to ensure the application scales effectively without dropping incoming traffic? (Select TWO.)

  1. Request AWS Support to pre-warm the Application Load Balancer to the anticipated traffic volume before the launch of the breaking news system.Answer
  2. Configure Aurora Auto Scaling to dynamically add Aurora Replicas to the DB cluster based on average reader CPU utilization.Answer
  3. C
    Configure Aurora Auto Scaling to dynamically provision Amazon RDS Multi-AZ standby instances to handle the dynamic read query loads.
  4. D
    Rely on the default automatic scaling of the Application Load Balancer to handle the instantaneous load, as it dynamically scales to accommodate sudden spikes within seconds.
  5. E
    Deploy an Amazon ElastiCache for Memcached cluster to store session state with multi-AZ replication and failover support.

Answer

Request AWS Support to pre-warm the Application Load Balancer, and configure Aurora Auto Scaling to dynamically add Aurora Replicas based on reader CPU utilization.
Pre-warming the Application Load Balancer ensures that the load balancer is provisioned with sufficient capacity to absorb the massive, immediate traffic spike without dropping connections. Simultaneously, configuring Aurora Auto Scaling to dynamically adjust the number of Aurora Replicas scales out the read backend to handle the surge in query volume effectively.

Step-by-Step Solution

1
Analyze the load behavior on the entry point (the Application Load Balancer) during an instantaneous surge.
Determine that the traffic spike from near-zero to 80,00080,000 concurrent readers occurs within three minutes, which exceeds the normal gradual scaling rate of an Application Load Balancer.
This shows that pre-warming is required to avoid dropped requests.
2
Evaluate options for database scaling to handle the high volume of read queries.
Determine that Amazon Aurora Replicas are the appropriate target for read traffic and can be scaled dynamically using Aurora Auto Scaling.
This addresses database read throughput constraints.
3
Eliminate sub-optimal or invalid options.
Discard options proposing RDS Multi-AZ standbys for read traffic, trusting the ALB to scale instantly without pre-warming, or using Memcached for multi-AZ replication.
This narrows the selection down to the two optimal and valid actions.

Key Concept

Handling sudden flash traffic on Application Load Balancers through pre-warming, and scaling read capacity dynamically using Aurora Replicas and Aurora Auto Scaling.
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Topics

Performance and Scalability Optimization

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