PCDE Applying Site Reliability Engineering Practices to a Service Practice Test 3 — 15 Questions

Question 1

An SRE team wants to define an SLO for a microservice that processes HTTP requests. They need an SLI that measures the proportion of requests that are answered within 200ms with a non-5xx status code. Which type of SLI should they use?

Accepted Answer

Request-based SLI counting good requests divided by total requests. A latency-based SLI with a threshold (200ms) combined with availability (non-5xx) is a request-based SLI measuring good requests (fast+successful) over total requests.

Answer

Availability-based SLI using a rolling window of 30 days

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Window-based SLI counting good minutes

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Throughput-based SLI measuring requests per second

Question 2

A team has an SLO of 99.9% availability over a 30-day month. They burn through their entire error budget in the first 10 days. Which of the following is the MOST appropriate immediate action according to SRE principles?

Accepted Answer

Freeze all feature releases and focus on reliability improvements. When error budget is exhausted, the team should halt all feature releases and focus on reliability improvements to prevent further degradation.

Answer

Reduce the error budget by lowering the SLO to 99%

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Deploy a new feature to increase user engagement

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Increase the SLO to 99.99% to act as a buffer

Question 3

An SRE team uses Cloud Monitoring to create an SLO for a service with a 99.9% availability target over 28 days. They set up a fast burn-rate alert on the error budget with a lookback window of 1 hour and a burn rate factor of 14. At what error budget consumption percentage will the alert fire?

Accepted Answer

When >2% of error budget is consumed in the last 1 hour. Fast burn alert fires when the error budget consumption rate over the lookback window exceeds the burn rate threshold. With a 1-hour window and 14x burn rate, the alert fires when consumption exceeds 14 times the expected burn rate for that window. Expected burn for 1 hour is (1/672) of total budget (28 days = 672 hours). So 14x = 14/672 = 2.08%. The alert fires when >2% consumed in 1 hour.

Answer

When >10% of error budget is consumed in the last 1 hour

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When >50% of error budget is consumed in the last 1 hour

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When >0.1% of error budget is consumed in the last 1 hour

Question 4

A team is automating toil reduction and needs to identify tasks that qualify as toil. Which of the following is a defining characteristic of toil according to SRE principles?

Accepted Answer

Work that has no enduring value. Toil is work that is manual, repetitive, automatable, has no enduring value, and scales linearly with service growth. One key characteristic is that it provides no enduring value; if the task were not done, the service would not suffer long-term loss.

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Work that requires deep domain expertise

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Work that is performed by junior engineers only

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Work that is critical to business operations

Question 5

A site reliability engineer wants to implement chaos engineering on a Google Kubernetes Engine (GKE) cluster by injecting network latency into pods of a specific deployment. Which tool or service should they use?

Accepted Answer

Chaos Mesh. Chaos Mesh is a Kubernetes-native chaos engineering platform that supports injecting faults like network latency, pod failures, and more on GKE.

Answer

GKE Sandbox

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Cloud CDN

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Traffic Director with HTTP fault filter

Question 6

An SRE team uses Cloud Monitoring to alert on error budget burn rate. They configure a slow burn alert with a 6-hour lookback window and a burn rate factor of 5. What is the purpose of this slow burn alert?

Accepted Answer

To detect a gradual increase in error rate that could exhaust budget over time. Slow burn alerts detect sustained, slower consumption of error budget that could still exhaust the budget before the SLO period ends. They give early warning for gradual degradation.

Answer

To trigger when error budget is completely exhausted

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To detect rapid spikes in error rate that could exhaust budget quickly

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To calculate the remaining error budget

Question 7

An organization wants to reduce toil by automating a recurring process: every night, a script must run Cloud Build to rebuild a Docker image and deploy it to a GKE cluster. The script currently requires manual invocation by an engineer. Which Google Cloud service can trigger this automation on a schedule without manual intervention?

Accepted Answer

Cloud Scheduler. Cloud Scheduler can trigger Cloud Build or Pub/Sub on a schedule, which can then trigger a Cloud Function or Workflow to run the build and deploy.

Answer

Workflows

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Cloud Tasks

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Cloud Functions

Question 8

An SRE team is creating a postmortem after a service outage. They want to ensure the process is blameless and focuses on systemic improvements. Which practice is central to a blameless postmortem?

Accepted Answer

Assigning action items with owners and due dates to prevent recurrence. A blameless postmortem focuses on identifying contributing factors and systemic issues rather than assigning blame to individuals. The 5 Whys technique helps drill down to root causes.

Answer

Determining the financial cost of the outage

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Escalating the issue to senior management

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Identifying the individual who caused the incident for performance review

Question 9

A team uses Traffic Director with Envoy proxies to manage traffic in a service mesh on Compute Engine. They want to introduce fault injection to test resilience by injecting a 5-second delay in 10% of requests to a specific backend service. Which resource should they configure?

Accepted Answer

An HTTP route rule with a fault injection filter. Traffic Director supports HTTP fault filter to inject delays and abort faults into traffic. The filter is configured as part of the routing rule for the backend service.

Answer

A forwarding rule with a URL map that includes a fault injection policy

Answer

A health check policy

Answer

A backend service with a fault injection policy in its traffic policy

Question 10

An SRE team is setting up an on-call rotation for incident response. They want to use a tool that integrates with Cloud Monitoring and can escalate incidents if not acknowledged. Which service should they integrate with Cloud Monitoring?

Accepted Answer

PagerDuty. Cloud Monitoring can send notifications to PagerDuty, OpsGenie, and other incident management tools. PagerDuty is a common choice for on-call rotations and escalation policies.

Answer

Cloud Pub/Sub

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Cloud Functions

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Cloud Run

Question 11

A team defines an SLO for a data pipeline: 99.9% of data records should be processed within 1 hour of ingestion. They need an SLI to measure this. Which SLI is most appropriate?

Accepted Answer

Pipeline freshness. Pipeline freshness measures the time it takes for data to be available after ingestion. This is commonly used for data processing SLOs.

Answer

Throughput

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Error rate

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Request latency

Question 12

An engineer needs to create an SLO in Cloud Monitoring for a service that processes requests. The SLO should measure the proportion of requests that complete successfully within 300ms. The metric type for successful requests is custom.googleapis.com/myapp/success_count and for total requests is custom.googleapis.com/myapp/total_count. Which type of SLO should they create?

Accepted Answer

Request-based SLO using two metrics (good count / valid count). Cloud Monitoring SLOs can be request-based using a ratio of good requests to total requests from two metrics. This is a request-based SLO with a metric distribution.

Answer

Availability SLO using a single metric for uptime

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Request-based SLO using a single distribution metric

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Window-based SLO with metric distribution

Question 13

An SRE team wants to implement a blameless postmortem culture after incidents. Which TWO practices are essential for a blameless postmortem?

Accepted Answer

Conducting a root cause analysis using the 5 Whys technique. A blameless postmortem focuses on systemic issues, not individual blame. Action items with owners and dates ensure follow-through. The 5 Whys technique helps identify root causes.

Answer

Escalating the incident to the executive team

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Assigning monetary fines to the team responsible

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Identifying the individual responsible for the incident

Question 14

A team needs to automate the reduction of toil in their operations. Which THREE of the following are valid strategies to reduce toil according to SRE principles?

Accepted Answer

Automating repetitive manual tasks using Cloud Functions. Toil reduction involves automating repetitive manual tasks. Creating self-service tools, automating with Cloud Functions, and using Workflows for orchestration are valid strategies. Limiting toil to 50% of time is a tracking goal. Scaling team size is not a toil reduction strategy.

Answer

Scaling the operations team to handle more manual work

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Setting a toil budget that limits toil to 50% of the team's time

Question 15

An SRE team is designing an incident management process. Which TWO components are part of a typical incident command structure?

Accepted Answer

Incident Commander. The incident command structure includes an Incident Commander (overall lead) and a Communications Lead (liaison for stakeholders). The SRE lead may be Incident Commander. Developer is a generic role; on-call engineer is a role but not part of the command structure per se.

Answer

Developer

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On-call engineer

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Product Manager