PCDOE Building and implementing CI/CD pipelines Practice Question
A company uses Spinnaker for continuous delivery across multiple GKE clusters. After a recent infrastructure change, the 'Canary' deployment strategy fails during the 'disable' phase of the old version. The error log shows: 'Unable to disable server group: Not authorized to perform compute.instanceGroups.update.' What is the most likely root cause?
⚠ Common exam trap
Google Cloud often tests the distinction between permissions errors and resource quota errors, leading candidates to incorrectly select quota-related options when the error message explicitly states 'Not authorized'.
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 Spinnaker service account lacks the compute.instanceGroups.update permission on the project.
The error 'Unable to disable server group: Not authorized to perform compute.instanceGroups.update' directly indicates an IAM permissions issue. In Spinnaker, the service account used to interact with GCP must have the compute.instanceGroups.update permission to manage instance groups during the disable phase of a canary deployment. Option C correctly identifies that the Spinnaker service account lacks this specific permission on the project.
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 GKE cluster has reached its maximum node quota.
Why it's wrong here
Quota issues would produce resource exhaustion errors, not authorization.
- ✗
The Cloud Deploy pipeline is missing the required IAM role for the Spinnaker service account.
Why it's wrong here
The error is from Spinnaker directly, not Cloud Deploy.
- ✓
The Spinnaker service account lacks the compute.instanceGroups.update permission on the project.
Why this is correct
Correct: Spinnaker uses this permission to disable old server groups.
- ✗
The Kayenta canary analysis service is not configured correctly.
Why it's wrong here
Kayenta handles metric analysis, not disabling server groups.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PCDOE practice question is part of Courseiva's free Google Cloud 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 PCDOE exam.