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.

• ✗

  Set a new default URL for the new revision.

  Why it's wrong here

  Setting a new default URL is an operation on the service's domain mapping, not on its revisions. A default URL (like the automatic *.run.app URL or a custom domain) always points to the service as a whole, and the actual routing to revisions is governed by the traffic block. Since you cannot assign a unique default URL to a specific revision for splitting purposes, this action has no bearing on distributing load between revisions.

• ✗

  Delete the old revision.

  Why it's wrong here

  Deleting the old revision would eliminate the very revision you need to receive a portion of the traffic during a gradual rollout. Traffic splitting is meaningful only when both the current and previous revisions are available; deleting the old one prevents any percentage from being sent to it and makes a quick rollback impossible. Keep the old revision and adjust percentages with update-traffic instead.

• ✓

  Create the new revision by updating the service with a new image tag.

  Why this is correct

  Updating the service with a new image tag, for example via `gcloud run deploy`, is what creates a new revision. A revision cannot be manually created in isolation—it is always the result of deploying a new container image or configuration change. This step is a prerequisite because the later `update-traffic` command must reference the new revision's name to assign it a percentage of incoming requests.

• ✗

  Enable VPC ingress for the new revision.

  Why it's wrong here

  Enabling VPC ingress controls the network path that requests use to reach the service, such as whether traffic is allowed only from a VPC network or from the public internet. This is entirely separate from traffic management, which decides how requests are routed among existing revisions once they reach the service. Adjusting VPC settings has no effect on the percentage distribution defined in the service's traffic block.

• ✓

  Use gcloud run services update-traffic to set traffic percentages.

  Why this is correct

  The `gcloud run services update-traffic` command is the standard tool for splitting traffic between two or more revisions. It lets you specify a percentage for each revision, for example `--to-revisions=NEWREV=25,OLDREV=75`, and the service will route that share of requests to each revision. This command also supports flags like `--to-latest` to send all traffic to the latest ready revision, making it flexible for canary deployments.

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