EX294 Coordinate rolling updates Practice Question
You are managing a rolling update of a 10-node web application cluster using Ansible. The application requires that at least 8 nodes remain available during the update to handle traffic. You have written a playbook that uses serial: 2 (updates 2 nodes at a time). During a test run, the playbook updates the first batch of 2 nodes successfully, but when it proceeds to the second batch, one of the nodes fails to restart the web service. However, the playbook continues and updates the remaining nodes. At the end, only 7 nodes are healthy, causing performance degradation. You need to ensure that if a batch fails to meet the minimum health requirements, the entire rollout is stopped and no further updates are applied. Which course of action should you take?
⚠ Common exam trap
Candidates often confuse retry mechanisms or error handling with the need for a batch-level health check and abort logic, assuming that retrying a failed task or ignoring errors will somehow prevent the overall rollout from continuing when health thresholds are breached.
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
✓
Use a rolling update strategy with serial: 2 and a post-task health check, and set max_fail_percentage to abort the play if the healthy node count drops below 8.
This approach uses `max_fail_percentage` at the play level to abort the playbook if a certain percentage of tasks fail. Combined with a post-task health check that fails when fewer than 8 nodes are healthy, the playbook stops if the healthy node count drops below the required threshold, preventing further updates and performance degradation. The `serial: 2` ensures nodes are updated in batches, and the health check verifies the minimum healthy count after each batch.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Add a retry loop to the service restart task with a delay and count of 5.
Why it's wrong here
Retries may help transient issues but do not abort the rollout if the service remains down.
- ✗
Set ignore_errors: yes on the service restart task to avoid failures stopping the playbook.
Why it's wrong here
ignore_errors would continue regardless of health, making the situation worse.
- ✓
Use a rolling update strategy with serial: 2 and a post-task health check, and set max_fail_percentage to abort the play if the healthy node count drops below 8.
Why this is correct
throttle and max_fail_percentage combined can enforce health thresholds and abort the rollout when conditions are not met.
- ✗
Increase serial to 3 to complete the update faster and reduce the chance of node failures.
Why it's wrong here
Increasing batch size increases the risk of losing more nodes simultaneously; does not stop on failure.
Go deeper
Related to this question
About these practice questions
One of 520 original EX294 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This EX294 practice question is part of Courseiva's free Red Hat 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 EX294 exam.