DOP-C02 CodeDeploy deployment failure troubleshooting Practice Question
A company uses AWS CodeDeploy for deploying applications to an Auto Scaling group of Amazon EC2 instances. The deployment is failing with the error 'The overall deployment failed because too many individual instances failed deployment, too few healthy instances are available, or some instances in your deployment group are experiencing problems.' Which two actions should the DevOps engineer take to troubleshoot and resolve the issue? (Choose two.)
⚠ Common exam trap
The trap here is that candidates often jump to scaling or configuration changes (like AllAtOnce) without first checking the instance-level logs, which are the definitive source for diagnosing deployment failures in CodeDeploy.
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
✓
Check the CodeDeploy agent logs on the failed instances to identify script errors or missing dependencies.
The CodeDeploy agent logs on each EC2 instance contain detailed error messages about script failures, missing dependencies, or permission issues that cause the deployment to fail. Checking these logs is the first step in diagnosing why individual instances are failing, as the agent executes the AppSpec lifecycle hooks and reports back to the CodeDeploy service.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Check the CodeDeploy agent logs on the failed instances to identify script errors or missing dependencies.
Why this is correct
The CodeDeploy agent writes detailed logs to /opt/codedeploy-agent/deployment-logs/codedeploy-agent-deployments.log, capturing script output, exit codes, and stack traces for each lifecycle event. Reviewing these logs on failed instances reveals whether the root cause is a missing dependency, a syntax error in an AppSpec script, or a permissions issue, enabling a targeted fix.
- ✗
Increase the size of the Auto Scaling group to ensure more instances are available.
Why it's wrong here
Increasing the Auto Scaling group's desired capacity adds more instances, but those instances will use the same launch template, user data, and deployment scripts that already failed. The failure is not caused by insufficient capacity, so scaling out merely replicates the identical error across additional resources, increasing the blast radius without addressing the underlying issue.
- ✓
Verify that the deployment group's Auto Scaling group has the correct tags and that the instances have the CodeDeploy agent installed.
Why this is correct
The deployment group maps to Auto Scaling groups through tags, so if the tags are misconfigured or absent, CodeDeploy will not discover or target the expected instances. Additionally, each target instance must have the CodeDeploy agent installed and running; verifying both conditions confirms that the deployment can actually reach the instances and is a standard prerequisite check before deeper troubleshooting.
- ✗
Change the deployment configuration to 'CodeDeployDefault.AllAtOnce' to bypass the error.
Why it's wrong here
Changing to CodeDeployDefault.AllAtOnce alters the deployment strategy by removing the failure threshold and launching the revision on every instance simultaneously, but it does not modify the AppSpec scripts or environment that caused the failure. Instead of bypassing the error, this configuration can turn a single-instance failure into a fleet-wide outage, so it is not a valid troubleshooting action.
- ✗
Redeploy the application using a different revision.
Why it's wrong here
Redeploying a different revision blindly assumes the current revision is defective, but the failure often stems from the deployment configuration, lifecycle script, or agent state rather than the artifact itself. Without first examining the agent logs to confirm a revision-specific defect, this approach wastes time and may repeat the same failure, while potentially introducing new compatibility issues.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The DOP-C02 exam frequently reuses these exact scenarios with slightly different constraints.
✓Check the CodeDeploy agent logs on the failed instances to identify script errors or missing dependencies.Correct answer▾
Why this is correct
The CodeDeploy agent writes detailed logs to /opt/codedeploy-agent/deployment-logs/codedeploy-agent-deployments.log, capturing script output, exit codes, and stack traces for each lifecycle event. Reviewing these logs on failed instances reveals whether the root cause is a missing dependency, a syntax error in an AppSpec script, or a permissions issue, enabling a targeted fix.
✗Increase the size of the Auto Scaling group to ensure more instances are available.Wrong answer — click to see why▾
Why this is wrong here
Increasing the group size does not address the underlying cause; it might mask the issue.
✗Change the deployment configuration to 'CodeDeployDefault.AllAtOnce' to bypass the error.Wrong answer — click to see why▾
Why this is wrong here
Changing the deployment configuration does not resolve the underlying issue; it may cause downtime.
✗Redeploy the application using a different revision.Wrong answer — click to see why▾
Why this is wrong here
Redeploying the same revision will likely fail again; the root cause must be addressed.
Analysis generated from the official DOP-C02blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DOP-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 DOP-C02 exam.