In this lesson, we’ll leverage a pre-configured Amazon CloudWatch dashboard to monitor an Auto Scaling Group (ASG) during a Fault Injection Simulator (FIS) experiment. This setup provides real-time insights into ELB health checks and ASG instance status, enabling you to track scaling behavior and resilience under controlled failures.Documentation Index
Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt
Use this file to discover all available pages before exploring further.
- An AWS FIS experiment configured to terminate or impair EC2 instances
- An ASG with
minCapacityset to a desired level - A CloudWatch dashboard pre-populated with the relevant widgets
Dashboard Widgets Overview
| Widget Name | Metrics Displayed | Purpose |
|---|---|---|
| ELB Host HealthCheck | Healthy vs. unhealthy instances | Monitors ELB health check results |
| ASG Instance Checks | Total, pending, and in-service instances | Tracks scaling events and lifecycle status |
How to Interpret the Charts
-
ELB Host HealthCheck
- Baseline: Starts with 2 healthy instances.
- During FIS: One instance is terminated → healthy count drops to 1.
- Recovery: ASG’s
minCapacity=2triggers a replacement → healthy count returns to 2.
-
ASG Instance Checks
- Pending: Instances being initialized after launch.
- InService: Fully operational, serving traffic.
- The graph pattern mirrors the ELB health trend, reflecting when the ASG spins up replacement instances.
If you terminate multiple instances at once or set a high desired capacity, the ASG may launch many replacements simultaneously. Monitor the ASG Instance Checks widget to avoid unexpected resource costs.