Google ACE Practice Question: Ensuring Successful Operation of a Cloud Solution

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  kubectl set traffic my-service --revision=my-service-00001=100

  Why it's wrong here

  kubectl is the command-line tool for Kubernetes, but Cloud Run is a fully managed serverless platform that does not expose Kubernetes API objects or accept kubectl commands. Even if it did, the syntax 'kubectl set traffic' does not exist for Cloud Run; traffic routing is controlled via the gcloud CLI or the Cloud Console. Attempting this would produce an unrecognized command or fail to connect to any cluster, leaving the traffic split unchanged and the latency issue unresolved.

• ✓

  gcloud run services update-traffic my-service --to-revisions=my-service-00001=100

  Why this is correct

  This is the correct, supported command for adjusting traffic on a Cloud Run service. The 'update-traffic' subcommand directly modifies the revision routing percents, and '--to-revisions' allows explicit targeting of a specific revision; here, setting 'my-service-00001=100' routes all live traffic to the known-good revision A. This immediately reduces load on the suspect revision B and is exactly how you roll back a bad deployment on Cloud Run.

• ✗

  gcloud run revisions delete my-service-00002

  Why it's wrong here

  Deleting revision B while it is still serving any user traffic will cause in-flight requests and subsequent connections to that revision to fail, creating outages or 404 errors for clients. Cloud Run requires that a revision receives zero traffic before it can be deleted; you must first shift 100% of traffic off the revision, usually via 'update-traffic', and only then delete it as a separate cleanup step. Direct deletion is therefore unsafe and not a valid immediate mitigation for high latency.

• ✗

  gcloud run services update my-service --set-revision my-service-00001

  Why it's wrong here

  The 'gcloud run services update' command is meant to alter service-level configuration such as environment variables, memory limits, concurrency, or container images, not traffic routing. There is no '--set-revision' flag in this command; attempting to use it would result in a command-line parsing error and no change to the service. To change which revision receives traffic, you must use the dedicated 'gcloud run services update-traffic' subcommand, whose flags are explicitly designed for traffic splitting.

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