In today’s cloud-first world, ensuring the resilience of your systems is paramount. Enter chaos engineering, a proactive approach to system reliability that tests your infrastructure’s ability to handle failures. With Azure Chaos Studio, Microsoft’s cloud-native chaos engineering platform, you can inject faults into Azure resources to validate their resilience.
Let’s explore how to execute a proper chaos experiment using Azure Chaos Studio, focusing on an e-commerce platform as our example.
What is Azure Chaos Studio?
Azure Chaos Studio enables you to run controlled chaos experiments directly in your Azure environment. With a variety of fault injections—from network disruptions to virtual machine shutdowns—you can simulate failures across your cloud infrastructure and assess your system’s robustness.
Steps to Run a Chaos Experiment with Azure Chaos Studio
1. Define the Objective
Begin by outlining what you want to test and the expected outcomes.
For example:
Our e-commerce platform processes thousands of transactions daily. A critical requirement is ensuring consistent transaction processing even if a virtual machine (VM) hosting our application layer fails.
Hypothesis:
“If one VM in the application layer is stopped, traffic will seamlessly reroute to other VMs in the load balancer without impacting user experience.”
Success Criteria:
- Checkout latency remains under 2 seconds.
- Error rate remains below 1%.
2. Understand Your System
Before initiating chaos, map out your system architecture and define steady-state behavior.
Example E-commerce Architecture in Azure:
- Frontend (Azure App Service): Serves web traffic for product catalog and checkout pages.
- Application Layer (VM Scale Set): Processes business logic with multiple VMs behind an Azure Load Balancer.
- Database (Azure SQL Database): Stores transaction data and product inventory.
- Payment Gateway (External Dependency): Handles payment processing.
Steady-State Metrics:
- Average response time for checkout requests: 1.2 seconds.
- Error rate: Less than 0.5%.
- Throughput: 500 transactions per minute.
3. Choose the Scope of the Experiment
Select the failure scenario you want to simulate. Start small and grow the scope over time.
For this example:
We’ll simulate the shutdown of a VM in the application layer to observe how the system behaves during failover.
4. Set Up Azure Chaos Studio
- Enable Chaos Studio in Your Azure Subscription:
- Navigate to the Azure portal.
- Search for “Chaos Studio” and enable it for your subscription.
- Register Resources for Chaos Experiments:
- Add your VM Scale Set to Chaos Studio using a Target Resource Group.
- Ensure permissions for fault injection are correctly configured.
- Create a Chaos Experiment:
- Go to the Chaos Studio blade and create a new experiment.
- Define experiment steps, including specific faults to inject.
5. Plan the Experiment
Define the type of fault and conditions for your test.
Fault for Our Experiment:
- Inject a “VM Stop” fault on one of the VMs in the application layer.
Experiment Configuration:
- Step 1: Start monitoring application latency, error rate, and throughput.
- Step 2: Inject the “VM Stop” fault.
- Step 3: Monitor how the load balancer distributes traffic across remaining VMs.
6. Execute the Experiment
Run the experiment in Azure Chaos Studio during a low-risk period.
Execution Steps:
- Start the chaos experiment.
- Azure Chaos Studio will trigger the “VM Stop” fault.
- Observe the system behavior through monitoring tools like Azure Monitor or Application Insights.
Key Metrics to Observe:
- Response time during VM failure.
- Error rates for checkout requests.
- Load balancer’s traffic distribution across active VMs.
7. Analyze Results
Once the experiment concludes, review the data to evaluate your system’s performance against the success criteria.
Example Findings:
- Positive Outcome: The load balancer redirected traffic, maintaining a checkout latency of 1.7 seconds.
- Issues Identified: A brief spike in error rates (2%) occurred immediately after the VM was stopped.
8. Mitigate Issues
Address any weaknesses uncovered during the experiment.
For Our Example:
- Investigate the error spike during failover and update the load balancer’s health probe settings to reduce failover time.
- Add redundancy to the application layer by scaling up the number of VMs.
9. Iterate and Expand
Expand the scope of experiments to test additional failure scenarios, such as:
- Simulating network latency between the application layer and Azure SQL Database.
- Testing payment gateway unavailability using fault injection.
- Simulating a complete zone failure in a multi-region deployment.
10. Automate Chaos Testing
Integrate Azure Chaos Studio experiments into your CI/CD pipeline for continuous validation of system resilience. Use Azure DevOps or GitHub Actions to trigger chaos experiments as part of your testing workflow.
Why Use Azure Chaos Studio?
Azure Chaos Studio simplifies chaos engineering for teams operating in the Azure cloud. Its integration with Azure resources, straightforward setup, and extensive fault library make it a powerful tool for testing system resilience.
Example Tools in Azure Chaos Studio
- Faults:
- VM Stop
- Network Latency
- Disk I/O Throttling
- Monitoring:
- Azure Monitor for system metrics.
- Application Insights for application-level performance.
Final Thoughts
Chaos engineering isn’t about breaking systems—it’s about building confidence. With Azure Chaos Studio, you can identify and address weaknesses in your Azure architecture before they affect users. By following this structured approach, you’ll ensure your systems are ready for real-world challenges.
What chaos experiment will you run with Azure Chaos Studio? Let us know in the comments!
