PAS-C01 Operations and Maintenance Practice Question
A company is running SAP on AWS and needs to patch the operating system of multiple SAP application servers. The servers are in an Auto Scaling group behind an Application Load Balancer. What strategy minimizes downtime?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Perform a rolling update by updating the Auto Scaling group's launch configuration with a new AMI.
A rolling update with a launch template allows replacing instances one at a time, maintaining capacity. Option A is wrong because creating a new Auto Scaling group and shifting traffic using Route 53 is more complex and may cause downtime during the traffic shift. Option B is wrong because patching all instances at once via SSM may cause simultaneous reboots, leading to downtime. Option D is wrong because stopping all instances, applying patches, then starting them causes downtime.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Create a new Auto Scaling group with patched instances and shift traffic using Route 53.
Why it's wrong here
Creating a new Auto Scaling group with patched instances and shifting traffic via Route 53 introduces a full DNS-propagated cutover, which incurs TTL delays and lacks the granular, per-instance health-check control that an Application Load Balancer provides. This approach is tempting because Route 53 weighted routing is commonly used for blue/green deployments across separate environments, but here the existing ALB can already drain connections and register patched instances incrementally, avoiding the downtime of a DNS-level switch.
- ✗
Use AWS Systems Manager Patch Manager to patch all instances at once.
Why it's wrong here
Patches may require reboots, causing simultaneous downtime.
- ✓
Perform a rolling update by updating the Auto Scaling group's launch configuration with a new AMI.
Why this is correct
A rolling update replaces instances gradually, maintaining availability.
- ✗
Stop all instances, apply patches, then start them.
Why it's wrong here
Stopping all instances causes complete downtime.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PAS-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PAS-C01 exam.