PCD Deploy Scalable and Highly Available Databases in Google Cloud Practice Test 4 — 15 Questions

Question 1

An engineer needs to create a Cloud SQL for PostgreSQL instance with high availability. Which configuration ensures automatic failover in less than 60 seconds if the primary zone fails?

Accepted Answer

Select a regional instance with synchronous standby in a different zone.. Cloud SQL HA uses a regional instance with a synchronous standby in a different zone within the same region. Automatic failover occurs within 60 seconds. Zonal instances do not provide HA. Cross-region replication is not supported for HA; it's used for disaster recovery.

Answer

Select a zonal instance with a read replica in a different zone.

Answer

Select a zonal instance with automatic storage increase enabled.

Answer

Select a cross-region replica for disaster recovery.

Question 2

A company is using Cloud SQL for MySQL and wants to offload read traffic to a replica for better performance. They also need the replica to be available for disaster recovery in a different region. What should they do?

Accepted Answer

Create a cross-region read replica in another region.. Cross-region read replicas serve both read scaling and disaster recovery. They can be promoted to primary in a different region. Same-region replicas do not protect against regional failures. External replicas are not necessary; Cloud SQL supports cross-region replicas natively.

Answer

Enable high availability on the primary instance.

Answer

Create a same-region read replica and use failover.

Answer

Use an external replica in another region via MySQL replication.

Question 3

An engineer needs to deploy Cloud Spanner with the ability to scale compute capacity automatically between 1000 and 6000 processing units based on load, with a target high-priority CPU utilization of 65%. Which configuration achieves this?

Accepted Answer

Create the instance with 1 node (1000 processing units) and enable autoscaling with min=1000, max=6000, target high-priority CPU=0.65.. Cloud Spanner auto-scaling uses processing units with min/max bounds and a high-priority CPU target. Nodes are fixed at 1000 processing units each, so auto-scaling with processing units is required to specify a range and target. The feature was introduced to allow finer-grained scaling than nodes.

Answer

Create the instance with 6 nodes (6000 processing units) and set autoscaling with min=1, max=6, target high-priority CPU=0.65.

Answer

Create the instance with 1000 processing units and enable autoscaling with min=1, max=6, target CPU=0.65.

Answer

Create the instance with 3 processing units and enable autoscaling with min=1000, max=6000, target CPU=0.65.

Question 4

A developer wants to connect to a Cloud SQL instance from a Compute Engine VM without whitelisting IP addresses and with automatic encryption. What should they use?

Accepted Answer

Use the Cloud SQL Auth Proxy.. Cloud SQL Auth Proxy provides secure, encrypted connections without IP allowlisting. It uses IAM for authentication and runs as a sidecar or on the client. Direct IP with SSL still requires IP allowlisting. Cloud SQL Connector libraries also provide secure connections but the proxy is the standard tool for VMs.

Answer

Use direct IP connection with SSL.

Answer

Use a Cloud SQL Connector library.

Answer

Use a Cloud VPN connection.

Question 5

A company wants to deploy a Bigtable instance for a production workload that requires high availability across zones. They also need to ensure consistent single-digit millisecond latency for reads. Which configuration should they choose?

Accepted Answer

Create a production instance with two clusters across two zones using SSD storage.. Bigtable replication across zones provides HA and read scaling. Production instances are required for production workloads. Development instances are limited and not for production. HDD is slower, not recommended for low latency. A single cluster does not provide zone-level HA.

Answer

Create a production instance with one cluster and enable replication within the cluster.

Answer

Create a production instance with one cluster in a single zone using SSD storage.

Answer

Create a development instance with two clusters across two zones using HDD storage.

Question 6

An engineer notices high CPU utilization on a Cloud Spanner instance and wants to identify the queries consuming the most resources. Which tool should they use?

Accepted Answer

Query Insights for Spanner.. Cloud Spanner's Query Insights provides query performance statistics, including CPU usage, latency, and execution counts. It helps identify problematic queries. Stackdriver (Cloud Monitoring) shows overall metrics but not per-query details. Key Visualizer is for Bigtable. Cloud Logging can show logs but not specific query resource consumption.

Answer

Cloud Monitoring (Stackdriver) dashboards for Spanner.

Answer

Key Visualizer for Bigtable.

Answer

Cloud Logging with query logs.

Question 7

Which Cloud SQL setting ensures that all client connections to the database use SSL?

Accepted Answer

Set the 'require_ssl' flag to 'on'.. The 'require_ssl' flag in Cloud SQL enforces SSL connections. If enabled, non-SSL connections are rejected. IAM database authentication controls login via IAM but does not mandate SSL. Private IP alone does not enforce SSL; it's still possible to connect without SSL over the private network.

Answer

Use private IP only.

Answer

Set the 'ssl_mode' to 'required'.

Answer

Enable IAM database authentication.

Question 8

A company is migrating an on-premises PostgreSQL database to Cloud SQL. They need to ensure minimal downtime and continuous replication during the migration. Which approach should they use?

Accepted Answer

Use Database Migration Service with continuous replication.. Database Migration Service (DMS) supports continuous replication from source to Cloud SQL using native PostgreSQL replication (logical replication). It minimizes downtime. Import/export involves downtime. Creating a read replica from on-prem is not directly supported. Cloud SQL does not support cross-region replicas from on-prem.

Answer

Use a cross-region replica from an existing Cloud SQL instance.

Answer

Export the database using pg_dump and import into Cloud SQL.

Answer

Create a Cloud SQL read replica of the on-premises database.

Question 9

An engineer needs to configure Firestore security rules for a mobile app where users can only read and write their own data. The user's UID is stored in the document field 'owner'. Which rule correctly restricts access?

Accepted Answer

allow read, write: if resource.data.owner == request.auth.uid;. The 'resource.data.owner' checks the document's 'owner' field, and 'request.auth.uid' is the authenticated user's UID. The condition ensures users can only access documents where they are the owner. Option A uses 'request.auth.uid' correctly. Option B uses 'request.auth.userId' which is not valid. Option C incorrectly uses 'resource.data.userId'. Option D uses 'request.auth.name' which is not the UID.

Answer

allow read, write: if resource.data.owner == request.auth.name;

Answer

allow read, write: if resource.data.owner == request.auth.userId;

Answer

allow read, write: if resource.data.userId == request.auth.uid;

Question 10

A company is evaluating Cloud Bigtable for a high-throughput write workload. They need to monitor disk usage and request latency. Which metrics should they monitor? (Select the best combination.)

Accepted Answer

disk/bytes_used and request_latency. Bigtable provides 'disk/bytes_used' for disk usage and 'request_latency' for latency. 'cpu/utilisation' is not a Bigtable metric; Bigtable uses 'cpu_load' and 'server_latency' but request latency is the key metric. 'database/queries' is a Cloud SQL metric. 'rows_deleted' is a Spanner metric.

Answer

cpu/utilisation and database/queries

Answer

disk/bytes_used and rows_deleted

Answer

request_latency and database/memory/utilisation

Question 11

An engineer is deploying AlloyDB for PostgreSQL and needs to support read scaling with automatic scaling of read replicas based on load. They also want to ensure minimal operational overhead. What should they use?

Accepted Answer

Create a read pool instance with autoscaling enabled.. AlloyDB read pool instances provide a set of read replicas that can be configured with autoscaling. The pool manages the number of replicas based on load (e.g., CPU utilization). 'Read pool autoscaling' is the feature. Cross-region replication is for disaster recovery, not read scaling. AlloyDB Omni is for on-premises. Manual read replicas require operational overhead.

Answer

Manually create additional read replicas and set up a load balancer.

Answer

Create multiple cross-region replicas.

Answer

Use AlloyDB Omni to deploy replicas on-premises.

Question 12

An engineer is designing a disaster recovery strategy for a Cloud SQL for SQL Server instance. They need to be able to fail over to a different region with minimal data loss. Which TWO actions should they take? (Choose two.)

Accepted Answer

Create a cross-region read replica.. Cross-region replicas provide asynchronous replication to another region, allowing promotion for DR. Point-in-time recovery can be used to restore to the latest state before a disaster, minimizing data loss. HA is zone-level, not cross-region. Export/import is not real-time. Backup is point-in-time but not continuous replication.

Answer

Export the database daily to Cloud Storage.

Answer

Use an external replica in another region.

Answer

Enable high availability (regional) on the primary instance.

Question 13

A company needs to store and analyze large amounts of log data with flexible schema and support for real-time analytics. They want to use a fully managed, serverless solution. Which THREE Google Cloud services could meet their needs? (Choose three.)

Accepted Answer

Cloud Logging. BigQuery is a serverless data warehouse for analytics. Firestore can store semi-structured data with real-time listeners (though not primarily for analytics). Cloud Logging is for storing and querying logs with built-in analytics. Cloud SQL is relational and not serverless. Datastore (Firestore in Datastore mode) is not serverless? Actually Firestore is serverless. But note: Datastore mode is also serverless. However, the question says 'analyze large amounts of log data' — BigQuery and Cloud Logging are ideal. Firestore can be used for flexible schema but not for large-scale analytics; but it is fully managed and serverless. The combination of BigQuery (analytics), Cloud Logging (log storage/query), and Firestore (flexible schema for real-time) is plausible. But perhaps Cloud Spanner is not serverless. The answer key: B, C, D.

Answer

Cloud SQL for PostgreSQL

Answer

Cloud Spanner

Question 14

An engineer needs to secure a Cloud SQL for MySQL instance that contains sensitive data. They want to ensure that only specific Compute Engine VMs in the same VPC can connect, and that all connections are encrypted. Which THREE steps should they take? (Choose three.)

Accepted Answer

Enable IAM database authentication.. Private IP restricts access to the VPC. SSL enforcement ensures encryption. IAM database authentication adds an extra layer of security by allowing IAM-based login. Public IP would expose the instance. Authorized networks are for public IP access, which is not desired. Cloud SQL Auth Proxy can be used but not necessary if using private IP with SSL; the proxy adds another layer but is not required for this basic encryption and access control.

Answer

Assign a public IP address to the instance.

Answer

Add the VMs' IP addresses to the authorized networks.

Question 15

A company is deploying a new web application on Google Cloud and needs a managed relational database with PostgreSQL compatibility. The database must support automatic failover within 60 seconds in case of a zone outage. Which database deployment option should they choose?

Accepted Answer

Cloud SQL regional HA configuration. Cloud SQL with regional HA configuration provisions a primary and a standby instance in different zones within the same region, using synchronous replication to enable automatic failover in under 60 seconds. This meets the requirement for high availability within a single region.

Answer

Cloud SQL single zone with automatic storage increase

Answer

Spanner multi-region configuration

Answer

AlloyDB with a read pool of 2 instances