PCDE Practice Test 43 — 15 Questions

Question 1

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 2

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

Answer

Cloud Tasks

Answer

Cloud Functions

Question 3

An SRE team wants to reduce toil associated with manual database schema migrations. They currently run SQL scripts manually during maintenance windows. Which Google Cloud service is most appropriate to automate this process in a repeatable way?

Accepted Answer

Cloud Build. Cloud Build is a CI/CD platform that can execute SQL migration scripts as part of a build pipeline. It integrates with Cloud Source Repositories and can trigger on schema changes. Cloud Functions and Workflows are more for event-driven workflows, not typical for database migrations.

Answer

Cloud Scheduler

Answer

Workflows

Answer

Cloud Functions

Question 4

What is the primary purpose of an error budget?

Accepted Answer

To balance reliability and innovation by allowing a controlled amount of failure. Error budgets are the permissible amount of unreliability (100% - SLO). They allow teams to balance reliability with feature velocity: if budget remains, teams can deploy new features; if depleted, focus on reliability.

Answer

To measure team performance for annual reviews

Answer

To define the maximum acceptable downtime in a contract

Answer

To track the total number of errors in a system

Question 5

A DevOps team is implementing distributed tracing for a microservices application on GKE. They want to ensure traces are exported to Cloud Trace with minimal overhead. Which TWO approaches should they consider? (Choose 2)

Accepted Answer

Instrument the application using the OpenTelemetry SDK and configure the OTel Collector to export to Cloud Trace. OpenTelemetry SDK and automatic instrumentation for GKE (via Anthos Service Mesh) are both valid. The Stackdriver Trace API is deprecated in favor of OpenTelemetry.

Answer

Configure a Prometheus metric to capture trace data

Answer

Use the Stackdriver Trace API directly from the application

Answer

Use the Cloud Monitoring API to send trace data

Question 6

A global application uses Cloud Trace to collect distributed traces. The current sampling rate of 100% is causing high costs and storage usage. The team wants to reduce sampling while still capturing representative data. Which THREE strategies should they consider?

Accepted Answer

Set a probabilistic sampling rate (e.g., 10%) in the OpenTelemetry SDK. Strategies to reduce trace volume: (1) Implement head-based sampling with a fixed rate like 10% in the OpenTelemetry SDK. (2) Use tail-based sampling via the OpenTelemetry Collector to sample based on error status or latency. (3) Sample based on request path — prioritize high-value endpoints. Disabling auto-instrumentation stops all traces; increasing rate worsens the issue; using only Cloud Trace API is not a sampling strategy.

Answer

Disable automatic instrumentation and only use manual instrumentation with Cloud Trace API

Answer

Increase the sampling rate to 100% to ensure no traces are missed

Question 7

Your team uses Cloud Monitoring to set up an alerting policy for high CPU utilization. You want the policy to trigger only if CPU usage exceeds 80% for at least 5 minutes. Which condition configuration should you use?

Accepted Answer

Set the duration field to 300 seconds. The 'duration' field in a metric threshold condition specifies how long the metric must violate the threshold before triggering. Setting duration to 300 seconds (5 minutes) achieves the requirement. Alignment period and retest window are separate concepts.

Answer

Set the alignment period to 300 seconds

Answer

Set the forecast horizon to 300 seconds

Answer

Set the retest window to 300 seconds

Question 8

You are designing a monitoring strategy for a GKE cluster. You need to collect application metrics, traces, and logs in a vendor-neutral way, and export them to Google Cloud. Which TWO components should you use? (Choose two.)

Accepted Answer

OpenTelemetry SDK. OpenTelemetry SDK is the vendor-neutral instrumentation library. The OTel Collector can receive data from SDKs and export to multiple backends including Cloud Monitoring, Cloud Trace, and Cloud Logging. Stackdriver agent is deprecated, and OpenCensus is legacy.

Answer

Cloud Logging agent

Answer

Stackdriver Monitoring agent

Answer

OpenCensus agent

Question 9

A microservice running on Cloud Run is logging structured JSON payloads. You want to correlate logs with distributed traces using Cloud Trace. Which field should you include in the log entry to enable automatic correlation?

Accepted Answer

Include the 'trace' field with the full trace URL. The 'trace' field in the structured log entry should be set to the trace ID in the format 'projects/PROJECT_ID/traces/TRACE_ID'. This enables Cloud Logging to link logs to traces. The 'spanId' field is for span ID, but the trace field is required for correlation.

Answer

Set the 'labels' field with the trace ID

Answer

Set the 'httpRequest' field with a reference to the trace

Answer

Include the 'spanId' field with the span ID

Question 10

An engineer needs to troubleshoot a performance issue where a specific function in a Go application is consuming excessive CPU. They want to identify the exact lines of code causing the bottleneck with minimal overhead. Which Google Cloud tool should they use?

Accepted Answer

Cloud Profiler. Cloud Profiler continuously profiles CPU, heap, and other resources with very low overhead (~0.5%). It provides flame graphs that show which functions consume the most CPU, helping identify hot functions. Error Reporting focuses on errors, Cloud Trace on latency, and Cloud Monitoring on metrics.

Answer

Error Reporting

Answer

Cloud Monitoring

Answer

Cloud Trace

Question 11

You are building a dashboard in Cloud Monitoring to display CPU utilization of Compute Engine instances. Which TWO chart types are appropriate for showing trends over time? (Select 2)

Accepted Answer

Stacked bar. Line charts and stacked bar charts are commonly used to show trends over time. Heatmaps show distributions, scatter plots show correlations, and scorecards show a single value.

Answer

Scatter

Answer

Scorecard

Answer

Heatmap

Question 12

You need to set up an alert that fires when any of your Compute Engine instances has been down (no metric data) for more than 10 minutes. Which condition type should you use?

Accepted Answer

Metric absent. The 'metric absent' condition fires when a metric stops reporting data for a specified duration. This is ideal for detecting instance downtime. 'Metric threshold' requires a value above/below a threshold; 'forecast' predicts future values; 'log match' is for log-based alerts (not applicable for instance up/down).

Answer

Metric threshold

Answer

Log match

Answer

Forecast

Question 13

Which notification channel can be used with Cloud Monitoring to trigger a custom workflow in Cloud Functions when an alert fires?

Accepted Answer

Cloud Pub/Sub. Cloud Pub/Sub is a notification channel that can trigger downstream services like Cloud Functions.

Answer

Slack via Pub/Sub

Answer

PagerDuty

Answer

Email

Question 14

You need to set up a logs-based alert that triggers when the 99th percentile of request latency exceeds 500ms in a 10-minute window. You create a logs-based distribution metric. Which THREE alert conditions are needed? (Select 3)

Accepted Answer

Reducer: 99th percentile. To alert on a percentile of a distribution metric, you need to use the distribution metric, configure the percentile reducer (99th), set an alignment period, and define a threshold condition.

Answer

Notification channel: SMS only

Answer

Condition type: Metric absence

Question 15

You are configuring a log-based metric that counts error log entries with severity ERROR. You need to set up an alert that fires when the count exceeds 100 in a 5-minute window. Which alert condition type and reducer should you use?

Accepted Answer

Metric threshold condition with reducer MEAN and alignment period 5 minutes. For log-based counter metrics, you use a metric threshold condition. The metric type is a counter (cumulative), so you need to compute the rate of change using the MEAN reducer (which for a counter gives the rate) to compare against a threshold.

Answer

Metric absence condition with reducer COUNT and alignment period 5 minutes

Answer

Forecast condition with reducer SUM and alignment period 5 minutes

Answer

Metric threshold condition with reducer COUNT and alignment period 5 minutes