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Professional Cloud Architect · Domain 6: Ensuring solution and operations excellence · 12% of the exam

Task 6.5: Evaluating quality control measures

Measuring quality with SLOs and error budgets, release gates, vulnerability scanning and checks on infrastructure changes.

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  • Quality control: error budgets, release gates and scanning

    Lesson coming

Sample questions

Try each one before opening the answer. Every option is explained, with the Google Cloud documentation page that proves it.

Question 1 · choose 1

A service has an availability SLO of 99.9% over 28 days. Halfway through the period its error budget is already spent, and product managers want to ship two new features this week. What should the team do under an error budget policy?

  1. ALower the SLO to 99% for the rest of the period so the releases can go ahead
  2. BShip the features and disable the SLO alerting policies until the features are stable
  3. CPause risky releases and put reliability work first until the budget recovers
  4. DShip the features now and recalculate the error budget at the next period
Show the answer and why
  • ALower the SLO to 99% for the rest of the period so the releases can go ahead

    Incorrect

    Moving the target to fit the releases removes the SLO's value as a quality control.

  • BShip the features and disable the SLO alerting policies until the features are stable

    Incorrect

    Silencing alerts hides the problem while users keep getting a degraded service.

  • CPause risky releases and put reliability work first until the budget recovers

    Correct

    A depleted error budget means further risky changes such as new releases are likely to break the SLO, so the policy shifts effort to reliability.

  • DShip the features now and recalculate the error budget at the next period

    Incorrect

    The budget is already spent for this period; shipping now knowingly breaks the objective.

Error budgets turn an SLO into a release gate: while budget remains, the team can take risk; once it is gone, reliability work comes first.

Question 2 · choose 2

A team is defining service level indicators for a public REST API to measure its quality. Which TWO measurements make good SLIs? (Choose TWO.)

  1. AThe average CPU utilization of the API's backend nodes
  2. BThe number of Pods running for the API in the cluster
  3. CThe proportion of requests served without a 5xx error
  4. DThe number of deployments the team ships each week
  5. EThe proportion of requests served in under 300 milliseconds
Show the answer and why
  • AThe average CPU utilization of the API's backend nodes

    Incorrect

    CPU use is a resource metric; users can see slow or failed requests while CPU looks fine.

  • BThe number of Pods running for the API in the cluster

    Incorrect

    Replica counts describe capacity, not the quality users receive.

  • CThe proportion of requests served without a 5xx error

    Correct

    Availability measured as the share of good requests reflects what users experience.

  • DThe number of deployments the team ships each week

    Incorrect

    How often the team ships says nothing about the quality users receive.

  • EThe proportion of requests served in under 300 milliseconds

    Correct

    Latency measured as the share of fast enough requests is a standard user-facing SLI.

Quality control starts with measuring what users experience. SLIs such as the ratio of good to total requests for availability and latency feed SLOs and error budgets.

Question 3 · choose 1

A team changes the prompts and model version of a customer-facing Gemini assistant every few weeks. Some changes have made answers worse in ways nobody noticed until customers complained. What quality control should the architect add before each change ships?

  1. ARun the Gen AI evaluation service on a fixed test set and compare the scores
  2. BLower the model's temperature so that its answers are more consistent
  3. CMonitor the endpoint's latency and error rate after each change has shipped to users
  4. DAsk one developer to try a few questions in the console before release
Show the answer and why
  • ARun the Gen AI evaluation service on a fixed test set and compare the scores

    Correct

    The evaluation service scores model outputs against criteria, so a candidate can be compared with the current version before release.

  • BLower the model's temperature so that its answers are more consistent

    Incorrect

    Lower temperature changes randomness, not whether the new prompt is better.

  • CMonitor the endpoint's latency and error rate after each change has shipped to users

    Incorrect

    Operational metrics do not catch answers that are wrong but delivered quickly.

  • DAsk one developer to try a few questions in the console before release

    Incorrect

    A handful of manual checks is not a repeatable quality gate.

Generative AI changes need their own quality gates. A fixed evaluation set scored by the evaluation service turns subjective quality into a release decision.

Question 4 · choose 1

A data pipeline loads sales tables in BigQuery that feed executive dashboards. Recently, null customer IDs and duplicated orders reached the dashboards. The team wants rules such as non-null and uniqueness checked on every load, with alerts when they fail. What should the architect use?

  1. ABigQuery table snapshots taken after each load
  2. BCloud Monitoring alerts on the runtime of each of the BigQuery load jobs
  3. CColumn-level access control on the customer column
  4. DKnowledge Catalog auto data quality scans with rules on the tables
Show the answer and why
  • ABigQuery table snapshots taken after each load

    Incorrect

    Snapshots preserve data for recovery; they do not check its quality.

  • BCloud Monitoring alerts on the runtime of each of the BigQuery load jobs

    Incorrect

    Job duration says nothing about nulls or duplicates in the results.

  • CColumn-level access control on the customer column

    Incorrect

    Access control limits who sees a column, not what values it holds.

  • DKnowledge Catalog auto data quality scans with rules on the tables

    Correct

    Auto data quality validates BigQuery data against defined rules on a schedule and can log alerts when the data does not meet them.

Quality control applies to data products as well as code. Rule-based data quality scans catch bad loads before they reach decision makers.

Question 5 · choose 2

A platform team wants Kubernetes manifests to follow rules, such as no privileged containers and required cost-center labels. It wants violations blocked at admission in the GKE clusters and also caught earlier, before changes are merged. Which TWO measures should the team use? (Choose TWO.)

  1. AKubernetes RBAC roles that limit who can deploy
  2. BPolicy Controller constraints enforced in the clusters
  3. CThe same constraints checked against manifests in CI
  4. DBinary Authorization attestations on every image
  5. ENetworkPolicies that isolate each team's namespace
Show the answer and why
  • AKubernetes RBAC roles that limit who can deploy

    Incorrect

    RBAC controls who may act, not whether a manifest follows the rules.

  • BPolicy Controller constraints enforced in the clusters

    Correct

    Policy Controller enforces and audits programmable policies in clusters as guardrails for security and compliance.

  • CThe same constraints checked against manifests in CI

    Correct

    Policy Controller supports a shift-left approach, catching non-compliant changes before they reach the cluster.

  • DBinary Authorization attestations on every image

    Incorrect

    Binary Authorization checks images, not the settings or labels in manifests.

  • ENetworkPolicies that isolate each team's namespace

    Incorrect

    NetworkPolicies control Pod traffic, not manifest content.

Quality control for infrastructure works best in layers: the same policies checked early in CI and enforced at admission time.

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