PCDE Applying Site Reliability Engineering Practices to a Service Practice Test 6 — 15 Questions

Question 1

A team wants to define an SLO for their service based on availability. Over a 30-day window, the service handled 1,000,000 requests, of which 999,500 succeeded. What is the achieved availability, and what is the error budget consumed if the SLO is 99.95%?

Accepted Answer

99.95% availability; error budget consumed 100%. Availability = successful / total = 999,500 / 1,000,000 = 99.95%. SLO target is also 99.95%, so the allowed error budget is 0.05% of requests = 500 failures. Actual failures = 500, so error budget consumed = 500/500 = 100%.

Answer

99.95% availability; error budget consumed 50%

Answer

99.95% availability; error budget remaining 100%

Answer

99.5% availability; error budget consumed 10%

Question 2

An SRE team wants to alert when the error budget burn rate exceeds 14x the allowed rate over a 1-hour window. Which Cloud Monitoring alert policy configuration is appropriate?

Accepted Answer

Alert on error budget burn rate > 14 over a 1-hour window. For fast burn alert, use a 1-hour window with a burn rate threshold of 14. The burn rate is calculated as the ratio of actual failures to the allowed error budget per time unit.

Answer

Alert on error budget burn rate > 14 over a 6-hour window

Answer

Alert on error budget burn rate > 5 over a 1-hour window

Answer

Alert on error budget burn rate > 8 over a 2-hour window

Question 3

A service has an SLO of 99.9% availability over 30 days. In the first 10 days, the service has already consumed 60% of the error budget. Which action best aligns with SRE principles?

Accepted Answer

Declare a change freeze and focus on improving reliability. With high error budget consumption early, the team should throttle new releases to avoid exhausting the budget. This is a typical SRE practice: if error budget is nearly depleted, slow down changes.

Answer

Ignore the budget and continue deploying as usual

Answer

Extend the SLO window to 60 days to dilute the budget

Answer

Increase the SLO to 99.99% to tighten reliability

Question 4

An engineer needs to reduce toil. Which of the following tasks is considered toil according to SRE principles?

Accepted Answer

Manually rotating service account keys every week. Toil is manual, repetitive, automatable, and has no enduring value. Manually rotating service account keys weekly is a classic example of toil.

Answer

Writing a postmortem after an incident

Answer

Designing a new microservice architecture

Answer

Reviewing code changes for a new feature

Question 5

A team wants to automate the response to a common incident: restarting a service when it becomes unhealthy. Which GCP service is best suited to trigger a Cloud Function based on a Cloud Monitoring alert?

Accepted Answer

Cloud Monitoring alert with notification channel to Pub/Sub. Cloud Monitoring alert notification channels can trigger a Cloud Function via Pub/Sub or webhook. This is the standard pattern for automated incident response.

Answer

Cloud Endpoints

Answer

Cloud Scheduler

Answer

Cloud Tasks

Question 6

What is the primary purpose of a blameless postmortem in incident management?

Accepted Answer

Document the timeline and technical root cause. Blameless postmortems focus on understanding contributing factors and improving systems, not assigning fault.

Answer

Identify the individual who caused the incident

Answer

Update the SLA to exclude the incident period

Answer

Assign monetary penalties to the responsible team

Question 7

A service uses Cloud SQL for MySQL. To test resilience, you want to inject latency into database queries. Which chaos engineering approach is most suitable on Google Cloud?

Accepted Answer

Use Traffic Director fault injection filter on the Envoy proxy sidecar. Chaos Mesh is a Kubernetes-native chaos platform that can inject faults into services running on GKE. For Cloud SQL, you would inject latency at the application layer using a sidecar proxy or by using a Chaos Mesh network fault, but the best option among these is to use a proxy sidecar with fault injection.

Answer

Use gcloud sql instances patch to add artificial delay

Answer

Use Cloud SQL's built-in maintenance to simulate latency

Answer

Deploy Cloud Functions to throttle the database connection

Question 8

An SRE team wants to track the amount of toil each week and ensure it does not exceed 50% of the team's time. Which approach is most aligned with SRE best practices?

Accepted Answer

Have each team member log their time and estimate toil percentage weekly. SRE best practice is to have team members estimate and track toil time weekly, aiming for under 50%. Using a simple spreadsheet is a valid approach to start.

Answer

Use Cloud Monitoring to automatically classify all tasks as toil

Answer

Use Cloud Tasks to queue up toil items and measure completion time

Answer

Set a Cloud Scheduler job to remind team members to automate toil

Question 9

Which of the following is NOT a characteristic of toil as defined by SRE?

Accepted Answer

Requires complex problem-solving. Toil is manual, repetitive, automatable, and has no enduring value. Complex design work is the opposite.

Answer

No enduring value

Answer

Repetitive

Answer

Manual

Question 10

During an incident, the incident commander decides to escalate to a higher severity level. Which of the following best describes the incident commander's primary responsibility?

Accepted Answer

Managing the incident response process and communications. The incident commander is responsible for coordinating response, communication, and prioritization, not necessarily fixing the issue.

Answer

Debugging the root cause of the incident

Answer

Writing the postmortem document

Answer

Implementing the fix

Question 11

A team uses Cloud Monitoring SLO monitoring with a request-based SLI for availability. They define good requests as those returning HTTP 200. Which configuration correctly creates this SLO?

Accepted Answer

good-request-count = successful requests, valid-request-count = total requests. For request-based SLO, define good-request-count as the number of successful requests and valid-request-count as total requests. Cloud Monitoring uses these metrics.

Answer

good-request-count = requests with latency < 500ms, valid-request-count = total requests

Answer

good-request-count = total requests, valid-request-count = successful requests

Answer

good-request-count = 200 responses, valid-request-count = 400+500 responses

Question 12

A team wants to implement a slow burn alert for error budget consumption. Which configuration should they use?

Accepted Answer

Alert on error budget burn rate > 5 over 6 hours. Slow burn alert uses a 6-hour window and a burn rate threshold of 5 (or similar). This allows detecting gradual budget consumption.

Answer

Alert on error budget burn rate > 2 over 12 hours

Answer

Alert on error budget burn rate > 14 over 1 hour

Answer

Alert on error budget burn rate > 20 over 30 minutes

Question 13

Which TWO are valid methods to define an SLI for a request-driven service? (Choose 2.)

Accepted Answer

Proportion of requests completed within a latency threshold. Common SLIs: proportion of successful requests (availability) and proportion of requests meeting a latency threshold.

Answer

CPU utilization of the server

Answer

Number of code commits per week

Answer

Number of running instances

Question 14

An SRE team wants to conduct chaos engineering on a GKE cluster to test resilience. Which TWO tools or services can be used? (Choose 2.)

Accepted Answer

Traffic Director fault injection. Chaos Mesh is a popular chaos engineering tool for Kubernetes. Traffic Director can also inject faults via Envoy sidecar proxy configuration.

Answer

Cloud Scheduler

Answer

Cloud Build

Answer

Cloud Run for Anthos

Question 15

Which THREE are components of an effective incident management process? (Choose 3.)

Accepted Answer

Blameless postmortem with action items. Key components: on-call rotation, incident command system, and postmortems with action items.

Answer

Automatic rollback of all changes during incidents

Answer

Monthly performance bonuses for on-call