Skip to main content
In this walkthrough, you’ll create a Fault Injection Simulator (FIS) experiment template that terminates 50% of instances in an Auto Scaling group. AWS FIS helps you build resilience by running controlled chaos experiments.

​
Prerequisites

  • An AWS account with permissions for FIS, EC2, IAM, and CloudWatch Logs
  • An existing Auto Scaling group tagged with experiment=ready
  • A service role (for example, fis-workshop-ec2-service-role) allowing FIS to terminate EC2 instances

​
Step 1: Open the FIS Console

  1. Sign in to the AWS Management Console.
  2. Navigate to Fault Injection Simulator under Resilience.
  3. In the sidebar, choose Experiment templates, then click Create experiment template.

​
Step 2: Define Experiment Template Details

On the Create experiment template page, complete the basic fields:
ParameterValueDescription
AWS accountYour current accountAutomatically populated
Namefis-workshop-asg-50-percentUnique template name
DescriptionTerminate half of the instancesHigh-level summary of the fault injection goal
Click Next to move on to action configuration.

​
Step 3: Configure the Termination Action

Actions specify the faults FIS injects. For this template:
  • Action name: terminate-instances
  • Action type: EC2 → Terminate instance
  • Targets: keep default (instances-target1)
  • Start after: leave blank (unused for single-action workflows)
The image shows a form for adding an action in a cloud management interface, specifically for terminating EC2 instances. It includes fields for name, description, action type, and target selection.

​
Step 4: Define Target Resources

Specify which instances FIS should target:
  1. Click Edit target next to instances-target1.
  2. Set Target name to FIS Workshop ASG 50%.
  3. Choose Resource type: EC2 instance.
  4. Under Target selection, choose Tags and filters.
Configure Tags and filters:
  • Tag filter
    • Key: experiment
    • Value: ready
  • Resource filter
    • Filter name: State name
    • Value: running
  • Selection mode
    • Percentage: 50%
This ensures only running EC2 instances tagged experiment=ready are considered, and exactly half are terminated.
The image shows a configuration interface for setting resource tags and filters, with options to add tags and filters, and a section for selecting a percentage mode.

​
Step 5: Select IAM Role & Logging

  1. Scroll to IAM role and select your FIS service role (e.g., fis-workshop-ec2-service-role).
  2. Choose a CloudWatch Logs group to capture FIS events.
No stop conditions are defined in this demo. In production, always add stop conditions (e.g., CPUUtilization thresholds) to avoid uncontrolled failures.

​
Step 6: Create the Experiment Template

Click Create template. A confirmation appears noting that no stop conditions exist—this is expected for this workshop. Confirm to finalize the template. Your experiment template is now ready. When executed, it will terminate 50% of the instances in the specified Auto Scaling group.
The image shows an AWS Resilience Hub interface, specifically the Fault Injection Simulator (FIS) section, displaying details of an experiment template designed to terminate half of the instances in an auto-scaling group.

Watch Video