Google ACE Practice Question: Ensuring Successful Operation of a Cloud Solution
You need to set up log-based alerting in Cloud Logging to send notifications when a specific error pattern appears in your application logs. Which TWO components are required to accomplish this?
⚠ Common exam trap
ACE often tests the confusion between log routing (sinks) and log alerting — candidates who think a log sink or Pub/Sub topic is required for alerting miss that the essential pair is a log-based metric plus an alerting policy.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
An alerting policy
Option A, an alerting policy, is required because it is the Cloud Monitoring resource that defines the condition to watch and the notification channels to fire when that condition is met, which is what actually sends the notifications. Option E, a log-based metric, is required because log-based alerting in Cloud Logging works by defining a metric that counts or extracts values from log entries matching the specified error pattern, and the alerting policy then evaluates that metric. Together, the log-based metric translates the log filter into a time series and the alerting policy triggers notifications when that series crosses the threshold. Option B, a log sink, is not required because sinks route or export log entries to destinations such as Cloud Storage or BigQuery and are not part of the alerting evaluation path. Option C, a Cloud Pub/Sub topic, is not required because Pub/Sub is only needed for log routing/export or for notification delivery if explicitly chosen as a channel, not for creating the log-based alert itself. Option D, an uptime check, is not required because uptime checks probe endpoint availability over HTTP/TCP and are unrelated to matching error patterns in log entries.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
An alerting policy
Why this is correct
The alerting policy is the actual alerting mechanism in Cloud Logging. It defines the conditions that trigger an incident, such as a threshold on a metric (e.g., a log-based metric exceeding a value) and specifies the notification channels (email, Slack, etc.) to receive alerts. Without an alerting policy, a log-based metric only counts or samples log entries; it does not perform any active monitoring or notify anyone.
- ✗
A log sink
Why it's wrong here
A log sink exports log entries from Cloud Logging to other destinations like Cloud Storage, BigQuery, or Pub/Sub. It is used for long-term retention, analysis, or streaming, but it does not evaluate log data for alerting conditions. Creating a sink alone will never trigger an alert; it only moves the data out of Logging.
- ✗
A Cloud Pub/Sub topic
Why it's wrong here
Cloud Pub/Sub can be a notification channel for an alerting policy, but a Pub/Sub topic itself is only a messaging infrastructure. You can publish alert notifications to a topic, but setting up a topic does not create an alert or define any monitoring condition. Alerts require a policy that references a metric and chooses a notification channel; the channel alone is passive.
- ✗
An uptime check
Why it's wrong here
An uptime check monitors the availability and latency of an external HTTPS or TCP endpoint from Google-managed locations. It does not inspect log content or support log-based conditions. You can configure alerting on an uptime check, but that is resource-availability monitoring, not log-based alerting; it is an entirely different tool from analyzing log entries.
- ✓
A log-based metric
Why this is correct
A log-based metric extracts information from log entries (e.g., counting occurrences of an error) and makes it available for monitoring and alerting. It is a named filter that transforms logs into a metric, which is the data source an alerting policy will watch. However, the metric itself does not send notifications or set thresholds; it merely provides the numerical value that the policy uses to decide whether to alert.
Go deeper
Related to this question
Learn chapter
BigQuery Views and Materialized Views
Key term
TCP
TCP (Transmission Control Protocol) is a core internet protocol that ensures data is sent reliably and in order between devices over a network.
Key term
Cloud Monitoring
Cloud monitoring is the process of observing, measuring, and managing an organization's cloud infrastructure and applications to ensure performance, availability, and security.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Google Cloud exam blueprint
This ACE practice question is part of Courseiva's free Google Cloud certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the ACE exam.