SOA-C02 Deployment, Provisioning, and Automation Practice Question
A SysOps administrator is using AWS CodeDeploy to deploy an application to an Auto Scaling group. The deployment fails with the error 'The overall deployment failed because too many individual instances failed deployment, too few healthy instances are available for deployment, or some instances in your deployment group are experiencing problems.' The deployment group has a minimum of 2 healthy instances. What should the administrator check FIRST?
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
✓
The ApplicationStop lifecycle event hook script in the AppSpec file
The ApplicationStop lifecycle event hook script in the AppSpec file often fails with a non-zero exit code, causing the deployment to fail with this error. The error indicates that too many instances failed or are unhealthy, and the most common cause is a faulty script. Option A is incorrect because the CodeDeploy agent version is not the first thing to check; the error is about instance failures during deployment, not agent issues. Option B is incorrect because the Auto Scaling group's minimum size is already set to 2, and the error is not about group size but about individual instance health. Option C is incorrect because a load balancer health check configuration problem would result in a different error related to health check failures, not the specific message about instance deployment failures.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The CodeDeploy agent version on the instances
Why it's wrong here
While an outdated or faulty CodeDeploy agent can cause deployment problems, it is not the primary suspect for this specific error. Agent version issues typically manifest as 'agent not found' or 'unable to connect to CodeDeploy' errors before lifecycle events are even attempted. Here, the deployment reaches the ApplicationStop hook, meaning the agent is running and able to execute the deployment steps. Thus, the agent version is unlikely to be the culprit; the failing hook script is the more direct and immediate cause.
- ✗
The Auto Scaling group's minimum size
Why it's wrong here
Although the Auto Scaling group's minimum size is set to 2, this is not the root cause of the error. The 'too few healthy instances' message occurs after instances have failed their deployment lifecycle events, causing them to remain in an unhealthy state. If the group were undersized, the ASG would launch additional instances to meet the minimum, but this would not fix a deployment script failure. The error reflects that instances are actively failing deployment, not that the group lacks capacity.
- ✗
The load balancer health check configuration
Why it's wrong here
The load balancer health check configuration affects how traffic is routed to instances, but it does not directly cause the deployment failure error. CodeDeploy uses load balancer health checks to deregister and re-register instances during the deployment workflow, yet the error message indicates a problem with instance-level deployment execution, not the load balancer's health check criteria. A misconfigured health check might delay traffic shifting, but it would not cause instances to fail the ApplicationStop hook or other lifecycle events. The instance deployment failure itself is what drives the error.
- ✓
The ApplicationStop lifecycle event hook script in the AppSpec file
Why this is correct
The ApplicationStop lifecycle event hook script in the AppSpec file is the correct cause. This hook runs on each instance before the new application revision is installed, and if it exits with a non-zero code or hangs, CodeDeploy marks that instance's deployment as failed. Each failed instance reduces the count of healthy instances, and once that count falls below the minimum healthy threshold, the overall deployment fails with the exact error observed. Therefore, checking this script for syntax errors, missing dependencies, or permission issues is the first troubleshooting step.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SOA-C02 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 SOA-C02 exam.