Top Google Cloud Platform (GCP) Interview Questions and Answers for 2025: Get Ready for Your Cloud Career

Megana Natarajan

If you are preparing for a position that involves cloud engineering, Google Cloud Platform interview questions are likely to be encountered. DevOps, data engineering, or solution architecture. Recruiters and real-world scenarios in their GCP interview questions to assess your understanding of how GCP services work together.

This blog covers the top 20 Google Cloud Platform interview questions along with succinct answers to help you be more confident in your future interviews. These questions will help you gain knowledge and clarity around vital GCP concepts, regardless of whether you are an experienced engineer reading up for an interview or a fresher learning about GCP for the first time.

GCP Interview Questions

What is Google Cloud Platform (GCP)?

Suggested Approach: Explain GCP and highlight its advantages.

Sample Answer: Google Cloud Platform, or GCP, is a collection of cloud computing services offered by Google. It is fueled by the same infrastructure that Google leverages for its own products, including Google Search and YouTube. It offers high-level software services that include compute, storage, networking, analytics, machine learning, and more, along with platform (PaaS) and infrastructure (IaaS).

The main benefits include: scalability, security, cost-efficiency, and integrated analytics tools such as BigQuery and an AI platform.

What are the core service categories in GCP?

Suggested Approach: Enumerate the main service categories and identify one or two vital services within each, along with their function.

• Compute – Compute Engine, Kubernetes Engine, App Engine
• Storage – Cloud Storage, Cloud SQL, Bigtable
• Networking – VPC, Load Balancing, Cloud CDN
• Big Data & ML – BigQuery, Dataflow, AI Platform
• Security & IAM – IAM, KMS, Security Command Center

Differentiate IaaS, PaaS, and SaaS in GCP.

Suggested Approach: Briefly define each model before mapping it to GCP examples.

Sample Answer: Infrastructure as a Service (IaaS): It offers virtualized computer resources, like storage and virtual machines. For example, Compute Engine, where you control the disk, operating systems, etc.

Platform as a Service (PaaS): Abstracts much of the infrastructure so you can focus on the data and application code. App Engine is a PaaS Solution in GCP. You launch your application, and the platform takes care of patching, scaling, and runtime.

Software as a Service (SaaS): It is a ready-to-use software program that can be accessed through an API or the web with little to no infrastructure needs. This could include third-party SaaS products that run on GCP or Google Workspace apps.

Interviewers can better understand your position and skills as a cloud practitioner if you are knowledgeable about these models.

What are regions and zones in GCP?

Suggested Approach: Describe how availability is ensured by GCP’s architecture.

Sample Answer: A zone is a deployment area inside a region, and a region is a specific geographic location. While multi-region deployments enhance disaster recovery, the use of multiple zones improves fault tolerance.

What is a Virtual Private Cloud (VPC)?

Suggested Approach: Explain its purposes and nature.

Sample Answer: In GCP, a virtual private cloud (VPC) is a network that differentiates resources. Custom IP ranges, subnets, routes, and firewall rules are all possible, ensuring hybrid connectivity and safe service-to-service communication.

What is the purpose of Compute Engine?

Suggested Approach: Give an explanation of GCE (managed virtual machine service), including its main features and common applications (legacy apps, custom operating systems, etc.)

Sample Answer: You can build and use virtual machines on Google’s infrastructure with the help of the GCD (Google Compute Engine) service. Important features include custom machine types, predefined machine types, persistent disks, live-migration of virtual machine hosts, and integration with other GCP services.

• You have legacy applications that require specific kernel or OS modifications.
• The VM configuration (CPU, memory, GPU, and local SSD) needs fine-grained control.
• On-premise virtual machines must be shifted and moved to the cloud.
• GCE is the recommended service if the use case is “I want full VM control”.

What is Google Kubernetes Engine (GKE)?

Suggested Approach: Define and compare using a compute engine.

Sample Answer: GKE is a managed Kubernetes service that simplifies container management, scaling, and deployment. It abstracts away cluster management for containerized workloads, in comparison to Compute Engine.

What are the Cloud Storage classes?

Suggested Approach: Give each class a name (Standard, Nearline, Coldline, Archive), and describe the cost implications and access patterns.

Sample Answer: There are different storage classes available in GCP Cloud Storage.

• Standard Storage: For data that is often accessed, or “hot”, such as user-served images.
• Nearline Storage: Used for backups and other data that is accessed less regularly than once per month.
• Coldline Storage: Used for archival data that is accessed less regularly than once a year.
• Archive Storage: The least expensive option for long-term, highly irregularly accessed data, such as compliance archives and disaster recovery snapshots.

Be mindful of cost, retrieval speed, and frequency of access when making your decision. For example, compliance logs might end up in Archive, user profile photos in Standard, and monthly backups in Nearline.

Being aware of storage classes demonstrates that you are cognizant of trade-offs and costs.

What is IAM in GCP?

Suggested Approach: Describe the structure and goal of IAM.

Sample Answer: Identity and Access Management (IAM) regulates who has access to what resources. It makes use of policies and roles. Basic, predefined, and custom roles are allocated to individuals, teams, or service accounts. Follow the least privilege principle.

Compare Cloud SQL, Cloud Spanner, and Bigtable.

Suggested Approach: Provide use cases and compare three database services: managed relational, globally distributed relational, and NoSQL wide-column.

Sample Answer: For conventional relational workload, Cloud SQL is a managed relational database service (MySQL, PostgreSQL, SQL Server). Use it when you need a simple relational database with popular SQL semantics.

• Cloud Spanner is a relational database that is globally distributed, horizontally scalable, and has high consistency across regions. It is ideal for high-scale systems that are deployed globally but still need SQL.
• Bigtable is a NoSQL wide-column database that is often used for time-series, Internet of Things, or analytics workloads. It is made for large-scale, low-latency reads and writes. Thus, you may select Cloud SQL if you have a standard web application, Spanner if you have a telecom billing system that is distributed globally, and Bigtable if you have petabytes of time-series data.

What is BigQuery?

Suggested Approach: Define BigQuery, explain serverless data warehousing, discuss its use of columnar storage, divide storage and computation, and integrate with other services.

Sample Answer: You can execute SQL-like queries on very large datasets (terabytes to petabytes) utilizing Google’s serverless, highly scalable data warehouse, BigQuery, without having to worry about maintaining infrastructure.

• It effectively scans big datasets by using columnar storage.
• Storage and computation are decoupled: Scaling occurs automatically, and you don’t have to control the hardware.
• It is integrated with other services like Dataflow, Pub/Sub for ingestion, and Data Studio for visualization.
• Pay-as-you-go pricing means that you only have to pay for the data that is processed and stored.

You should preferably use BigQuery when you need a data warehouse solution without the operational overhead, high-performance analytics, or ad hoc querying of sizable data sets.

What is Pub/Sub, and when is it used?

Suggested Approach: Describe Pub/Sub (messaging/event-driven), topics/subscriptions, push vs. pull, and use cases (microservices, decoupling, real-time streaming).

Sample Answer: Pub/Sub is GCP’s messaging service, compatible with real-time pipelines and event-driven architectures. It allows you to publish messages to topics, which are then pushed or pulled to one or more subscriptions.

Pub/Sub is used for real-time analytics ingestion pipelines or when you want to decouple systems, such as when a frontend publishes user events and a backend processes them asynchronously. It abstracts the messaging infrastructure and is scalable. It is a vital component of modern GCP microservices and data pipeline design.

How does autoscaling work in GCP?

Suggested Approach: Describe the general processes: Define the minimum and maximum size, monitoring, and scaling policies (CPU, schedule) for example group or node pool. Later, discuss best practices (set alerts, avoid over-provisioning).

Sample Answer: To set up autoscaling in GCP (for example, in managed instance groups for Compute Engine).

• Establish an instance template and a managed instance group.
• Select a scaling mode (such as CPU utilization, load balancing capacity, custom metric, or schedule) and allow autoscaling for that group.
• Establish target utilization thresholds (such as 60% CPU) and a minimum and maximum number of instances.
• Set up monitoring and alerts, and configure health checks to be cognizant of scaling events.
• You define node pools and activate autoscaling (also called cluster autoscaler or node-pool autoscale) for GKE. It expands or contracts in response to resource demand and pending pods.

Best practices include monitoring actual usage, ensuring your workloads can gracefully handle instance termination, and avoiding setting the minimum too high (waste cost) or the maximum too low (risk of throttling).

This answer demonstrates your comprehension of dynamic infrastructure scaling on GCP.

Compare Cloud Functions and Cloud Run.

Suggested Approach: Describe each and make a note of when to use each.

• Cloud Functions: Microtasking, lightweight, and event-driven.
• Cloud Run: Runs full containers serverless, with more flexibility

For individual tasks, use Cloud Functions; use Cloud Run for containerized apps that need unique runtimes.

What is Infrastructure as Code (IaC)?

Suggested Approach: Define IaC, discuss its benefits (repeatability, versioning, audit), and make reference to third-party (Terraform) or GCP-native tools (Deployment Manager).

Sample Answer: The practice of handling and provisioning infrastructure (networks, virtual machines, storage, etc.) using machine-readable definition files (code) as opposed to manual methods is referred to as Infrastructure as Code (IaC). Some of the top benefits include: consistency, version control, auditability, and automation.

• Google Cloud Deployment Manager – a native GCP tool for defining resources via YAML templates.
• Terraform – a broadly used open-source tool that supports GCP via provider plugins, letting you manage infrastructure across clouds.

As part of CI/CD, you would build Terraform files or templates that define networks, virtual machines, IAM policies, etc. You would commit them to source control and have them automatically deployed. This demonstrates your comfort level with modern infrastructure procedures.

How does GCP handle logging and monitoring?

Suggested Approach: Find relevant services.

Sample Answer: Cloud Logging collates resource logs, whereas Cloud Monitoring monitors metrics and uptime. Both can export data to BigQuery or cause alerts, and they both integrate into dashboards.

How can expenses on GCP be optimized?

Suggested Approach: Mention practical ways to cut costs.

Sample Answer: Leverage committed-use, sustained-use, and autoscaling discounts. Set up budget alerts for visibility, disable unused resources, and choose the best storage classes.

How can we ensure high availability in GCP?

Suggested Approach: Clearly explain failover and redundancy techniques.

Sample Answer: Use load balancing, managed databases, replication, and deployment across multiple zones and regions. Decrease downtime by automating backups and designing for stateless architectures.

What are the key steps in migrating workloads to GCP?

Suggested Approach: Outline a high-level process.

1. Assess and plan
2. Configure IAM and networking
3. Transfer data using Database Migration Service
4. Deploy workloads
5. Validate performance and cost post-migration

What are the best practices for GCP security?

Suggested Approach: Provide a list of actionable steps, like network segmentation, audit logging, least privilege, encryption in transit and at rest, regular compliance checks, and VPC Service Controls.

Sample Answer: Here are some common GCP security and compliance best practices:

Apply least-privilege IAM: Avoid giving roles such as “Owner” too many permissions; instead, provide roles only the required permissions.

• Use service accounts for applications rather than user credentials.
• Encrypt data both in transit (TLS) and at rest (GCP encrypts by default, but key management is critical). If required, consider using Customer-Supplied Keys (CSEK) or Customer-Managed Encryption Keys (CMEK).
• Use logging and monitoring to identify threats. Enable audit logs (Cloud Audit Logs) and gather them centrally.
• Use secure defaults and update patching: Ensure the images are current and stop using deprecated APIs.

Compliance frameworks: Map your environment in accordance with GCP’s compliance documentation (HIPAA, GDPR, and PCI).

• Use Secret Manager or KMS to store keys and secrets.
• To identify unforeseen usage, assess booking/billing, and IAM audit logs on a regular basis.

This answer shows that you’re more than thinking of “how to launch a VM” and are instead focusing on executing enterprise-grade, secure workloads in GCP.

Conclusion

The principles and real-world applications of designing, securing, and scaling workloads in the cloud are covered in these GCP interview questions. You can discuss trade-offs, architecture, and cost with confidence in any technical interview if you are well-versed with these Google Cloud Platform interview questions and their logic.