Reliability and Business Continuity

A SysOps administrator manages an Application Load Balancer (ALB) that distributes traffic to an Auto Scaling group spanning three Availability Zones. After a recent scaling event, the group has 6 instances in us-east-1a, 2 in us-east-1b, and 2 in us-east-1c. Users report that the instances in us-east-1b and us-east-1c are receiving noticeably higher CPU utilization than those in us-east-1a. What is the most likely cause of this uneven load?

A SysOps administrator manages an EC2 Auto Scaling group behind an Application Load Balancer. The application takes about 4 minutes to fully initialize and pass the ALB target group health checks after an instance launches. The Auto Scaling group is configured to use ELB health checks. Administrators notice that newly launched instances are being terminated and replaced repeatedly, causing a launch loop that never stabilizes. What is the MOST likely cause and appropriate fix?

A SysOps administrator manages a stateful web application on EC2 instances in an Auto Scaling group behind an Application Load Balancer. Each instance maintains long-running upload sessions. During scale-in events, users report that in-progress uploads are abruptly terminated before completing. The administrator needs to ensure that instances complete active sessions before being terminated. Which approach BEST solves this problem?

A SysOps administrator manages a stateless web application behind an Application Load Balancer. Leadership wants to reduce compute costs by up to 70% while maintaining high availability across three Availability Zones. The application can tolerate individual instance interruptions but must always keep at least 40 instances running to serve baseline traffic. The current Auto Scaling group uses a single On-Demand instance type. Which configuration change BEST meets these requirements?

A company runs a stateless web application on an EC2 Auto Scaling group spanning three Availability Zones behind an Application Load Balancer. After a large scale-in event followed by manual instance terminations during troubleshooting, a SysOps administrator notices that 8 of the 10 running instances are concentrated in a single Availability Zone. The team is concerned that an AZ failure could remove most of the fleet's capacity. Which action will BEST ensure the Auto Scaling group maintains a balanced distribution of instances across the Availability Zones going forward?

An e-commerce company runs a web application on an EC2 Auto Scaling group behind an Application Load Balancer. Every business day, traffic spikes sharply at exactly 9:00 AM when a marketing email is sent, and the surge lasts about two hours. During this window, the application currently responds slowly because target tracking scaling reacts only after CloudWatch metrics breach thresholds, leaving a few minutes of under-provisioning. The company wants capacity available the moment the spike begins. What is the MOST effective way to address this?

A SysOps administrator manages an EC2 Auto Scaling group behind an Application Load Balancer for a web application. The application experiences unpredictable, large traffic spikes where CPU utilization can jump from 40% to 90% within a minute. The current target tracking policy targeting 50% average CPU adds instances too slowly during these sudden bursts, causing brief periods of degraded performance. The administrator needs the scaling response to be more aggressive as the breach magnitude increases. Which scaling configuration change BEST addresses this requirement?

A SysOps administrator manages a web application behind an Application Load Balancer with an EC2 Auto Scaling group. Traffic patterns are unpredictable, and CPU utilization stays low even during peak periods because the workload is I/O bound. During traffic surges, users experience slow responses even though the CPU-based target tracking policy never triggers scale-out. The administrator needs the group to scale based on how much traffic each instance actually handles. Which scaling configuration BEST addresses this?

A SysOps administrator manages an EC2 Auto Scaling group behind an Application Load Balancer for a web tier. The group uses a target tracking scaling policy set to keep average CPU utilization at 50%. During a marketing event, traffic spiked and the group scaled out correctly. After the event, traffic dropped sharply, but the administrator notices the group is removing instances very slowly, keeping many instances running for a long time at low CPU. The administrator wants faster scale-in while still avoiding thrashing during brief traffic dips. What is the MOST appropriate action?

A financial services company runs a production workload on an Amazon Aurora MySQL cluster in us-east-1. The disaster recovery plan requires an RPO of less than 1 second and an RTO of under 5 minutes in a second Region. Management also wants the DR Region to serve low-latency read traffic for reporting users located there during normal operations. Which approach BEST meets all of these requirements?

A SysOps administrator manages a production application that stores data in an Amazon RDS for PostgreSQL Multi-AZ instance and several Amazon EBS volumes in the us-east-1 Region. The compliance team requires that all backups be retained for 90 days and that a copy of every backup exist in the us-west-2 Region to meet disaster recovery objectives. The solution must be centrally managed and automated with minimal operational overhead. Which approach BEST meets these requirements?

A SysOps administrator manages backups for a fleet of EC2 instances and RDS databases using AWS Backup. During a recent audit, the compliance team asked for proof that the backups are actually recoverable and meet the documented 4-hour RTO. The administrator wants an automated, repeatable way to validate that recovery points can be successfully restored on a recurring schedule, without manually launching restores each time. Which approach should the administrator implement?

A financial services company must ensure that its EBS and RDS backups cannot be deleted or have their retention periods shortened by anyone—including administrators with full AWS Backup permissions—for a mandatory 7-year compliance retention. A SysOps administrator has already created an AWS Backup vault and a backup plan that copies backups into it. Which action will enforce this immutable retention requirement?

A gaming company runs a serverless backend that stores player session data in a DynamoDB table in us-east-1. The business now requires that players in Europe experience low read/write latency and that the application continue serving writes even if the us-east-1 Region becomes unavailable. The team wants a fully managed solution with minimal application changes and no manual failover steps. Which approach BEST meets these requirements?

A SysOps administrator manages a fleet of EC2 instances in us-east-1 backed by encrypted EBS volumes using a customer managed KMS key. The company's disaster recovery policy requires that volume backups be recoverable in us-west-2 within 4 hours if the primary Region becomes unavailable. Currently, automated EBS snapshots are created daily by a Data Lifecycle Manager (DLM) policy, but they exist only in us-east-1. What is the MOST appropriate way to meet the DR requirement?

A SysOps administrator manages an EC2 Auto Scaling group behind an Application Load Balancer for a Java application. Each instance takes about 12 minutes to fully bootstrap because it downloads dependencies, warms a large cache, and initializes the JVM before it can serve traffic. During sudden traffic spikes, target tracking scaling launches new instances, but customers experience elevated latency and errors for several minutes while the new instances complete initialization. The administrator must reduce the time it takes for scaled-out instances to begin serving requests while minimizing ongoing cost. What should the administrator do?

A SysOps administrator manages an Application Load Balancer fronting an Auto Scaling group of EC2 instances that serve long-running file uploads averaging 90 seconds. During scale-in events and deployments, users report that in-progress uploads fail with dropped connections. The default deregistration delay is currently in effect. What is the MOST appropriate action to prevent these failed requests?

A SysOps administrator manages an Application Load Balancer (ALB) that routes traffic to an Auto Scaling group of EC2 instances running a web application on port 8080. Users report intermittent HTTP 502 errors. The instances all pass EC2 status checks and show as 'InService' in the Auto Scaling group, but the ALB target group reports several targets as 'unhealthy'. The application process on the affected instances has crashed, though the operating system remains running. What should the administrator do to ensure unhealthy instances are automatically replaced?

A company runs a critical order-processing application backed by an Amazon RDS for PostgreSQL Multi-AZ DB instance. During a recent AZ disruption, the primary instance failed over to the standby, but the application experienced an extended outage because it could not reconnect to the database. On investigation, you find the application configuration references the primary instance's private IP address directly. Which change will ensure the application automatically reconnects after future Multi-AZ failovers with minimal downtime?

A SysOps administrator manages a production Amazon RDS for PostgreSQL database (Single-AZ) with automated backups enabled and a 7-day retention period. At 14:32, a developer runs an incorrect script that deletes several critical tables. The team discovers the problem at 15:10 and needs to restore the data to the state it was in just before the deletion, while minimizing downtime for the running instance. What is the MOST appropriate action?