PCDE Practice Exam 54 — 20 Questions

Question 1

A DevOps engineer is designing a landing zone for a large enterprise. Which THREE components are essential for a well-architected landing zone? (Choose THREE.)

Accepted Answer

A shared VPC project to host common network resources.. Option A is correct because a shared VPC project (host project) centralizes network resources such as subnets, firewall rules, and routes, allowing service projects to attach to the shared VPC and enforcing consistent network policy across the enterprise. Option B is correct because a centralized security project is where shared security services like Cloud Armor, Security Command Center, and Cloud DLP are provisioned, giving security teams a single control plane for policy and monitoring across the landing zone. Option C is correct because a centralized logging project aggregates audit logs from all projects into one location, which is essential for compliance, retention, and enterprise-wide visibility. Option D is not essential because billing accounts are typically organized per business or organizational unit rather than per team, and a single billing account per team is not a landing zone design requirement. Option E is not essential because separate projects per developer for sandboxes are not a core landing zone component; sandbox environments are usually provided through a controlled, shared sandbox project or folder rather than one project per developer.

Answer

A single billing account per team.

Answer

A separate project per developer for sandbox environments.

Question 2

An SRE team wants to perform fault injection testing on a GKE cluster by injecting network latency into a specific set of pods. Which tool should they use?

Accepted Answer

Chaos Mesh on GKE.. Chaos Mesh is a Kubernetes-native chaos engineering tool that supports fault injection, including network latency, pod failure, and stress testing. It can be deployed on GKE to inject network latency into specific pods. Thus, Chaos Mesh is the appropriate tool.

Answer

Cloud Functions with network disruption script.

Answer

Traffic Director fault injection.

Answer

Google Cloud Armor.

Question 3

A company is experiencing slow query performance in Cloud SQL for PostgreSQL. Which TWO tools can help identify the root cause?

Accepted Answer

Cloud Monitoring. Query Insights (B) is the purpose-built tool for Cloud SQL for PostgreSQL that captures per-query latency, execution plans, and wait-event data, letting you pinpoint slow or high-frequency queries causing the slowdown. Cloud Monitoring (A) is also correct because it provides metrics such as CPU utilization, memory usage, disk I/O, and query latency for the Cloud SQL instance, helping correlate resource saturation with the slow query behavior. Together they cover both query-level and infrastructure-level diagnosis. Cloud Logging with error reporting (C) is for capturing and aggregating log/error events, not for profiling query execution or resource metrics. Cloud Profiler (D) analyzes CPU and heap usage of application code, not database query performance. Cloud Trace (E) traces request latency across distributed services, but it does not expose PostgreSQL query plans or instance-level database metrics.

Answer

Cloud Logging with error reporting

Answer

Cloud Profiler

Answer

Cloud Trace

Question 4

You are designing a database architecture for a global e-commerce application. The application requires low-latency reads in multiple regions and must handle up to 100,000 writes per second globally. Which Google Cloud database solution should you use?

Accepted Answer

Cloud Spanner with multi-region configuration.. Cloud Spanner with a multi-region configuration is the correct choice because it provides globally distributed, strongly consistent relational database service with horizontal scalability, supporting over 100,000 writes per second across multiple regions while maintaining ACID transactions and low-latency reads via regional replicas. This meets the requirements of a global e-commerce application needing high write throughput and low read latency in multiple regions.

Answer

Firestore in multi-region mode.

Answer

Bigtable with multiple clusters.

Answer

Cloud SQL with cross-region replication.

Question 5

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

Accepted Answer

Requires complex problem-solving. Toil as defined by SRE is work that is manual, repetitive, automatable, tactical, devoid of enduring value, and scales linearly with service growth. 'Requires complex problem-solving' is the opposite of toil; toil is typically mechanical and does not require deep cognitive effort or novel problem-solving.

Answer

No enduring value

Answer

Repetitive

Answer

Manual

Question 6

A data engineer is building a BI reporting layer in BigQuery. The source data includes JSON logs with nested fields. Analysts need to query nested arrays efficiently. Which approach is best?

Accepted Answer

Use SQL and UNNEST to directly query nested arrays.. BigQuery natively supports nested and repeated fields via the UNNEST operator, which flattens arrays into rows for SQL-based querying. This approach leverages BigQuery's columnar storage and efficient array handling, allowing analysts to query nested arrays directly without data duplication or additional ETL, which is optimal for BI reporting performance.

Answer

Load the data into separate tables for each array.

Answer

Flatten all nested fields into separate tables.

Answer

Create a view that flattens the data.

Question 7

Which TWO schema design practices help reduce write contention in Cloud Spanner?

Accepted Answer

Use a hash prefix in the primary key to distribute writes across splits.. Using a hash prefix in the primary key distributes write operations uniformly across multiple splits (tablets). Cloud Spanner splits data based on key ranges; without a hash prefix, sequential writes (e.g., monotonically increasing keys) concentrate on a single split, causing hot spots and write contention. A hash prefix ensures that each new row lands on a different split, balancing the write load.

Answer

Use a timestamp prefix in the primary key to sort by time.

Answer

Use interleaved tables to keep related rows together.

Answer

Decrease the number of splits by using a less granular primary key.

Question 8

A BI developer is designing a BigQuery dataset for a sales dashboard. Which column naming convention is considered a best practice for column names in BI reports?

Accepted Answer

Use descriptive, snake_case names (e.g., total_revenue).. BigQuery column names are case-insensitive but must follow standard SQL naming rules. Using descriptive snake_case (e.g., total_revenue) improves readability, avoids ambiguity, and is consistent with BigQuery's own system tables and best practices for BI tools like Looker or Tableau, which often expect clean, underscore-separated identifiers.

Answer

Use names with spaces (e.g., Total Revenue).

Answer

Use short, cryptic abbreviations (e.g., tr).

Answer

Use camelCase names (e.g., totalRevenue).

Question 9

You need to monitor the disk usage of your Cloud SQL instances and receive an alert when disk usage exceeds 80%. Which GCP service should you use to set up this alert?

Accepted Answer

Cloud Monitoring. Cloud Monitoring (formerly Stackdriver) is GCP's native service for collecting metrics, creating alerting policies, and notifying on thresholds such as disk usage exceeding 80%. Cloud SQL instances automatically publish metrics like `disk/utilization` to Cloud Monitoring, so you can create an alerting policy on that metric with an 80% threshold. This is the standard, supported way to monitor and alert on Cloud SQL resource usage.

Answer

Cloud Audit Logs

Answer

Cloud Logging

Answer

Cloud Billing reports

Question 10

A company uses Memorystore for Redis with the 'volatile-lru' eviction policy. They notice that recently added keys with TTL are being evicted even though there is still memory available. What is the most likely cause?

Accepted Answer

The volatile-lru policy evicts only keys with an expiry set, and there are many keys without expiry occupying memory. The 'volatile-lru' eviction policy in Memorystore for Redis evicts only keys that have a TTL (expiry) set, using an LRU (Least Recently Used) algorithm among those keys. If many keys without expiry are consuming memory, the eviction process will still target only the volatile keys, even if overall memory is not fully exhausted, because the policy is constrained to evict only from the subset of keys with TTLs. This explains why recently added keys with TTL are being evicted prematurely — the non-volatile keys are 'protected' from eviction, forcing the eviction of volatile keys to free memory.

Answer

The allkeys-lru policy would be more appropriate

Answer

The maxmemory setting is not configured

Answer

The maxmemory-policy is misconfigured

Question 11

You are running a Memorystore for Redis instance with persistence disabled. The application requires high availability and data durability after a zone failure. What is the most cost-effective approach?

Accepted Answer

Use a Standard tier instance with cross-zone replication.. Standard tier Memorystore for Redis instances provide cross-zone replication by default, ensuring automatic failover and data durability in the event of a zone failure. This meets the high availability and data durability requirements without the need for manual exports or complex multi-region setups, making it the most cost-effective solution.

Answer

Use a Basic tier instance and schedule periodic exports to Cloud Storage.

Answer

Enable persistence using the AOF or RDB configuration in Memorystore.

Answer

Deploy a Redis Cluster across multiple regions using Memorystore.

Question 12

A company uses Cloud Monitoring to create an SLO for a service. They want to define a request-based SLO with a ratio of good requests to valid requests. Which of the following is a valid way to define the SLI in Cloud Monitoring SLOs?

Accepted Answer

Select a metric for good requests and a separate metric for total valid requests, then define the SLI as good-request-count / valid-request-count. Cloud Monitoring request-based SLOs define an SLI as a ratio of two time series: a 'good' service filter and a 'total' (valid) service filter. The SLI is computed as good-request-count / valid-request-count, which is exactly what option B describes. This ratio-based approach is the canonical way to express availability or success-rate SLOs in Cloud Monitoring.

Answer

Use a distribution metric for latency and set a threshold for good latency

Answer

Create a custom metric for requests and use Cloud Monitoring's built-in availability SLI for HTTP services

Answer

Use a single metric that indicates success (1 for success, 0 for failure) and set a threshold filter

Question 13

A financial services company uses Cloud Spanner for transaction processing. They need to ensure zero downtime during a schema change that adds a new column with a default value to a large table. Which approach should the Database Engineer take?

Accepted Answer

Use ALTER TABLE to add the column; Spanner handles schema changes online.. Cloud Spanner supports online schema changes, including adding columns with default values, without requiring a maintenance window or causing downtime. Spanner applies schema updates asynchronously across all nodes while the database remains fully available for reads and writes, making it the ideal approach for zero-downtime requirements.

Answer

Create a new table with the new column, then use a fan-out pattern to write to both tables until the old table is deprecated.

Answer

Use an ALTER TABLE statement during a maintenance window.

Answer

Drop the table and recreate it with the new schema.

Question 14

A company is planning to migrate a large on-premises MySQL database (5 TB) to Cloud SQL. They need to choose the appropriate Cloud SQL edition. Which two factors should they consider? (Choose two.)

Accepted Answer

Maximum storage capacity supported by each edition.. Option C is correct because Cloud SQL editions differ in the maximum storage they support, and a 5 TB database requires verifying that the chosen edition can accommodate that data volume plus growth. Option D is correct because the editions also differ in performance limits such as maximum IOPS and throughput, which directly affect whether the migrated MySQL workload can meet its performance requirements. Options A, B, and E are not edition-specific differentiators: regional high availability, automated backups, and VPC network integration are Cloud SQL features available across editions rather than factors that determine which edition to select.

Answer

Availability of regional high availability.

Answer

Automated backup capabilities.

Answer

Integration with VPC networks.

Question 15

A company uses Cloud Spanner and needs to retain backups for 365 days for compliance. What is the maximum backup expiration period that can be set for a Spanner backup?

Accepted Answer

365 days. Spanner backups can have an expiration time set to a maximum of 365 days from the creation time. After that, the backup is automatically deleted.

Answer

30 days

Answer

Unlimited

Answer

90 days

Question 16

What is the primary benefit of using Workload Identity Federation over service account keys when authenticating workloads running outside Google Cloud?

Accepted Answer

It eliminates the need to create and manage long-lived service account keys, reducing the risk of key exposure.. Workload Identity Federation lets external workloads (on AWS, Azure, GitHub, or on-premises) exchange their native identity token for short-lived Google Cloud credentials, so no long-lived service account key JSON file is ever created or stored. This removes the primary risk of key leakage, rotation overhead, and accidental commits of key files to source control. The core benefit is eliminating long-lived credentials, not performance or multi-account support.

Answer

It allows using multiple service accounts simultaneously.

Answer

It enables workloads to run without any service account.

Answer

It provides higher performance for authentication requests.

Question 17

A team uses Cloud Build to build and push Docker images to Artifact Registry. They need to ensure that only images built from the main branch and signed by a trusted key can be deployed to GKE using Binary Authorization. Which THREE components must be in place?

Accepted Answer

A Binary Authorization attestor configured to verify the attestation key. Option A is correct because Binary Authorization requires an attestor resource that is configured with the trusted public key (from KMS or PKIX) so that it can cryptographically verify attestations attached to the image before deployment. Option B is correct because the attestation itself must be created and signed during the build; a Cloud Build step uses the KMS asymmetric signing key to produce a DSSE/attestation payload and then calls the Binary Authorization API to attach the signed attestation to the image digest. Option E is correct because the Binary Authorization policy must include a cluster or namespace rule that requires at least one attestation from the trusted attestor, otherwise unsigned images would still be admitted. Option C is not required because a Cloud Deploy canary strategy is a deployment-progression feature and does not enforce image provenance or signing. Option D is not required because Artifact Registry vulnerability scanning provides security insights on images but does not verify signatures or attestations for Binary Authorization admission.

Answer

A Cloud Deploy delivery pipeline with a canary strategy

Answer

An Artifact Registry repository configured with vulnerability scanning

Question 18

Your Cloud SQL for MySQL instance is experiencing unusually high disk usage. You need to identify the cause. Which metric should you monitor in Cloud Monitoring?

Accepted Answer

Binary log disk usage. Binary logs in MySQL store all data changes (e.g., INSERT, UPDATE, DELETE) and can consume significant disk space, especially under heavy write workloads or if retention is misconfigured. Monitoring 'Binary log disk usage' directly reveals whether accumulated binary logs are the primary cause of high disk usage, which is a common issue in Cloud SQL for MySQL.

Answer

InnoDB row reads

Answer

CPU utilization

Answer

Query latency

Question 19

A developer wants to add a composite index in Firestore to support a query that filters on two fields: 'status' (equality) and 'createdAt' (range). How should the index be configured?

Accepted Answer

Create a composite index with fields 'status' (ascending) and 'createdAt' (ascending).. Firestore requires a composite index when a query combines an equality filter on one field with a range filter on another. The index must list the equality field first ('status') followed by the range field ('createdAt'), with ascending order for both to support the range query efficiently. This matches the Firestore index definition rules for composite indexes.

Answer

No index is needed; single-field indexes are automatically created.

Answer

Create a composite index with fields 'createdAt' (ascending) and 'status' (ascending).

Answer

Add an index exemption on the 'status' field to force index creation.

Question 20

A company needs to store raw event logs for future BI analysis. The logs are semistructured with varying fields. Which BigQuery data type should they use to store the event payload?

Accepted Answer

JSON. BigQuery's JSON data type is designed to store semistructured data with varying fields, such as raw event logs. It allows schema flexibility, efficient querying of nested fields using JSON functions like `JSON_EXTRACT`, and avoids the need to predefine a rigid schema, which is ideal for BI analysis of event payloads.

Answer

ARRAY

Answer

STRING

Answer

FLOAT64