PCDE Practice Test 42 — 15 Questions

Question 1

A team needs to create an alert that triggers when the 99th percentile latency of a service exceeds 500ms for at least 10 minutes. Which alerting configuration is correct?

Accepted Answer

Metric threshold condition with alignment period 10 min, reducer PERCENTILE_99, based on 'latency' metric.

Answer

Absent condition with duration 10 min, based on 'latency' metric.

Answer

Metric threshold condition with alignment period 10 min, reducer MEAN, based on 'latency' metric.

Answer

Metric threshold condition with alignment period 10 min, reducer COUNT, based on 'latency' metric.

Question 2

A team wants to define an SLO for a microservice that processes batch jobs. The service is considered healthy if each batch completes within 60 minutes. There are 100 batches per day. Which SLI should be used?

Accepted Answer

Window-based SLI with good-minutes / total-minutes. A window-based SLI measures the proportion of good minutes (or windows) over total minutes. Since the service has a time-bounded objective (60 minutes per batch), a window-based SLI that counts each minute as 'good' if the oldest incomplete batch is less than 60 minutes old is appropriate. Request-based SLIs are for request/response patterns.

Answer

Latency SLI: proportion of batches under 60 minutes

Answer

Request-based SLI with good-request-count / valid-request-count

Answer

Availability SLI: successful batch completions / total batch completions

Question 3

An application running on GKE needs to send custom metrics to Cloud Monitoring. The team wants to use a vendor-neutral instrumentation approach that also supports traces and logs. Which solution should they choose?

Accepted Answer

Use OpenTelemetry SDK and OTel Collector to export to Cloud Monitoring and Cloud Trace. OpenTelemetry is a vendor-neutral standard for observability (metrics, traces, logs). The OpenTelemetry Collector can run as a DaemonSet on GKE and export data to Cloud Monitoring and Cloud Trace.

Answer

Use the Cloud Monitoring API directly from the application to write metrics

Answer

Use Prometheus client library and scrape metrics with Managed Service for Prometheus

Answer

Use the Stackdriver Monitoring client library

Question 4

During an incident, the incident commander delegates tasks to multiple teams. Which communication model is MOST effective to reduce noise?

Accepted Answer

Use a single incident channel where all teams post updates.. The recommended approach is to use a single communication channel (e.g., a dedicated chat room) for all incident-related updates, and the incident commander coordinates via that channel.

Answer

Use email for updates to avoid real-time noise.

Answer

Each team communicates in separate channels.

Answer

All updates go through the incident commander only.

Question 5

An SLA guarantees 99.9% monthly uptime. The team's SLO is 99.95% and error budget is 0.05%. What is the maximum allowed downtime per month according to the SLA?

Accepted Answer

43.8 minutes.. 99.9% uptime allows 0.1% downtime. Per month (30 days = 43,800 minutes), 0.1% is 43.8 minutes. The SLO is stricter but the question asks for SLA allowance.

Answer

7.2 hours.

Answer

21.9 minutes.

Answer

4.38 hours.

Question 6

Which of the following best describes 'toil' in SRE?

Accepted Answer

Manual, repetitive work that provides no enduring value and scales linearly with service growth. Toil is work that is manual, repetitive, automatable, and does not provide enduring value. It scales with service growth.

Answer

Work that is creative and requires deep domain knowledge

Answer

Automating infrastructure provisioning

Answer

Incident response and on-call duties

Question 7

You are implementing a chaos engineering experiment on a GKE cluster using Chaos Mesh. You want to test the resilience of a microservice by injecting a 5-second delay into 50% of HTTP requests to a specific service. Which Chaos Mesh resource should you use?

Accepted Answer

HTTPChaos. Chaos Mesh provides different chaos types: PodChaos (kill pods), NetworkChaos (delay/loss), HTTPChaos (HTTP fault injection). HTTPChaos directly injects faults into HTTP requests, allowing delay injection with a percentage. Traffic Director fault injection is for services mesh but not Chaos Mesh. So HTTPChaos is correct.

Answer

NetworkChaos

Answer

Traffic Director fault injection

Answer

PodChaos

Question 8

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

Answer

Assigning monetary fines to the team responsible

Answer

Identifying the individual responsible for the incident

Question 9

During an incident, an SRE team uses an incident command system. Which role is responsible for coordinating communication and resources, but not for technical debugging?

Accepted Answer

Incident Commander. In incident command, the Incident Commander (IC) focuses on coordination, communication, and resource management, leaving technical debugging to the Operations Lead or other technical roles.

Answer

Subject Matter Expert

Answer

Operations Lead

Answer

Scribe

Question 10

An SRE team wants to automate a manual process that involves multiple steps and conditional logic (e.g., if a backup fails, retry with a different method). Which TWO Google Cloud services can they use to orchestrate this workflow? (Choose 2 answers)

Accepted Answer

Cloud Composer. Cloud Workflows and Cloud Composer (based on Apache Airflow) are both orchestration services that can handle complex workflows with branching, retries, and conditionals. Cloud Functions is for individual functions, Cloud Build is for CI/CD, and Pub/Sub is for messaging.

Answer

Pub/Sub

Answer

Cloud Functions

Answer

Cloud Build

Question 11

A team wants to visualize real-time CPU utilization across a fleet of Compute Engine instances in a single dashboard. Which chart type in Cloud Monitoring is most appropriate?

Accepted Answer

Line chart. Line charts are ideal for time-series data like CPU utilization over time, showing trends and variations. Stacked bar charts are better for categorical comparisons, heatmaps for density, and scatter plots for correlation. For multiple instances over time, line charts are standard.

Answer

Stacked bar chart

Answer

Scatter plot

Answer

Heatmap

Question 12

Your application uses structured logging in JSON format. You want to ensure that each log entry is automatically correlated with the corresponding trace in Cloud Trace. Which field must be included in the JSON payload?

Accepted Answer

"trace" field with the trace ID formatted as projects/PROJECT_ID/traces/TRACE_ID. Cloud Logging correlates logs with traces via the 'logging.googleapis.com/trace' field (or 'trace' in the LogEntry), which should contain the trace ID in the format 'projects/[PROJECT_ID]/traces/[TRACE_ID]'. The 'httpRequest' field is for HTTP request data, 'severity' for log level, and 'labels' for custom metadata. Only the trace field provides correlation.

Answer

"severity" field set to "ERROR"

Answer

"httpRequest" object with requestUrl and status

Answer

"labels" field containing custom metadata

Question 13

An engineer wants to create a dashboard that shows the number of HTTP 5xx errors per minute from an application that writes structured logs. The application logs are in Cloud Logging. Which approach should be used?

Accepted Answer

Create a log-based metric with a counter for log entries containing '5xx' and use it in a dashboard.

Answer

Export logs to BigQuery and run a query every minute to count errors.

Answer

Use the Cloud Monitoring API to create a custom metric for error counts from logs.

Answer

Create an alert policy that triggers on error logs and counts them via a notification channel.

Question 14

An SRE team wants to implement chaos engineering on their GKE cluster. Which TWO options are valid tools or services for injecting faults into GKE workloads?

Accepted Answer

Chaos Mesh. Chaos Mesh is a dedicated chaos engineering platform for Kubernetes. Traffic Director's HTTP fault filter can inject faults at the proxy level for services within a mesh. Both can be used on GKE.

Answer

Cloud Audit Logs

Answer

Cloud Endpoints

Answer

Cloud Scheduler

Question 15

Error Reporting automatically groups similar exceptions. Which Google Cloud services does Error Reporting integrate with to provide additional context?

Accepted Answer

Cloud Logging and Cloud Trace. Error Reporting integrates with Cloud Logging to show log entries associated with errors, and with Cloud Trace to show trace details. Cloud Monitoring provides metrics, but not direct context per error. Cloud Profiler is for CPU/memory profiles, not error context.

Answer

Cloud Trace and Cloud Profiler

Answer

Cloud Logging and Cloud Monitoring

Answer

Cloud Monitoring and Cloud Profiler