Cloud-Computing Interview Questions

Cloud Technology refers to the delivery of computing services—such as servers, storage, databases, networking, software, analytics, and intelligence—over the internet (“the cloud”) to offer faster innovation, flexible resources, and economies of scale.

A cloud is essentially a combination of:

• Networks
• Hardware
• Storage
• Interfaces
• Services

It allows users to access and use these resources as a service, without owning or managing physical infrastructure.

Cloud Technology Users:

• End-user: The person who uses the cloud services such as apps, storage, or computing power.
• Business Management User: Oversees the cloud usage, service selection, and compliance, ensuring that business goals align with the cloud services.
• Cloud Service Provider: Manages the cloud infrastructure and provides services to users. Examples include AWS, Microsoft Azure, and Google Cloud.

Cloud Delivery Models refer to specific sets of IT resources and services offered by cloud providers to end-users. These models define how cloud services are provided, accessed, and managed.

Common Cloud Delivery Models:

• Software as a Service (SaaS): Delivers software applications over the internet. Users can access them via a web browser without managing the underlying infrastructure.
  Example: Google Workspace, Microsoft 365
• Platform as a Service (PaaS): Provides a platform allowing customers to develop, run, and manage applications without dealing with the infrastructure.
  Example: Google App Engine, Heroku
• Infrastructure as a Service (IaaS): Offers virtualized computing resources such as servers, storage, and networking on a pay-as-you-go basis.
  Example: Amazon EC2, Microsoft Azure VM
• Function as a Service (FaaS): Allows execution of code in response to events without managing servers, often used for microservices and event-driven applications.
  Example: AWS Lambda, Azure Functions
• Anything/Everything as a Service (XaaS): A broad category that includes all types of services provided over the internet, such as Database-as-a-Service (DBaaS), Security-as-a-Service (SECaaS), etc.

These delivery models offer flexibility, scalability, and cost-effectiveness to meet different business and technical needs.

Cloud Storage Levels define how data is structured and accessed within cloud storage systems. Each level provides a specific method for storing and interacting with data, suited for different use cases and performance needs.

The primary levels of cloud storage are:

• Files: Data is grouped into files organized in directories or folders. This is typical for traditional file systems and user-facing storage.
  Example: Google Drive, Dropbox
• Blocks: The lowest level of storage. Data is divided into fixed-size blocks and accessed individually. Used in raw storage devices such as virtual hard drives.
  Example: Amazon EBS (Elastic Block Store)
• Datasets: Data is structured in a tabular, record-based format, often used in big data or analytical platforms.
  Example: Google BigQuery, AWS Redshift
• Objects: Data is stored along with metadata in a flat structure. Objects are accessed via web APIs and are ideal for scalability and unstructured data.
  Example: Amazon S3, Azure Blob Storage

Each storage level corresponds to a different cloud storage mechanism and interface, allowing applications to access and manage data according to their architecture and needs.

In cloud computing architecture, various roles (called performers or actors) collaborate to deliver, manage, and consume cloud services. These roles are defined in the NIST Cloud Computing Reference Architecture.

The five major performers are:

• Cloud Provider: The entity responsible for making cloud services available to consumers. It manages infrastructure, software, and platform services (e.g., AWS, Microsoft Azure, Google Cloud).
• Cloud Consumer: The user or organization that consumes cloud services and resources from the cloud provider.
• Cloud Broker: Acts as an intermediary between cloud providers and consumers to help find, negotiate, and manage cloud services. They may enhance service delivery through aggregation, customization, or integration.
• Cloud Carrier: Provides connectivity and transport between the cloud provider and the cloud consumer. This includes network and communication infrastructure (like ISPs and VPN providers).
• Cloud Auditor: Conducts independent assessments of cloud services, security controls, and performance to ensure compliance with regulations and business goals.

These actors work together to ensure that cloud services are effectively delivered, secure, and aligned with business requirements.

Microservices are a software architecture style where an application is structured as a collection of small, independent services that communicate over well-defined APIs.

Each microservice is:

• Loosely Coupled: Services are independent and changes in one service don’t affect others.
• Independently Deployable: Each service can be deployed without redeploying the whole application.
• Scalable: Individual services can scale independently based on demand.
• Focused: Each service is designed around a specific business capability or functionality.

Microservices evolved from monolithic architecture challenges, where large applications (often with 100,000+ lines of code) became difficult to manage, scale, and innovate.

By using microservices, developers can build more resilient, agile, and maintainable applications that support continuous delivery and deployment.

The Cloud Computing Architecture is a combination of SOA (Service Oriented Architecture) and EDA (Event Driven Architecture), designed to deliver scalable, flexible, and reliable cloud services.

It consists of several key components:

• Client Infrastructure
• Application
• Service
• Runtime Cloud
• Storage
• Infrastructure
• Management
• Security

The architecture is divided into two main parts:

1. Frontend

The Frontend refers to the client side of the cloud computing system. It includes user interfaces and applications that clients use to access cloud services and resources.

2. Backend

The Backend is the cloud itself, managed by the cloud service provider. It includes resources, servers, data storage systems, and the underlying security and management systems needed to support cloud services.

This layered architecture enables on-demand access to computing resources, scalability, high availability, and strong security controls in the cloud environment.

Software as a Service (SaaS) is a cloud computing delivery model where applications are hosted by a service provider and made available to users over the Internet.

Instead of installing and maintaining software on individual computers or servers, users can access SaaS applications through a web browser. This model eliminates the need for complex software and hardware management.

SaaS is commonly used for applications such as email, customer relationship management (CRM), collaboration tools, and productivity software.

Cloud service providers are commercial vendors or companies that offer cloud-based services and infrastructure to consumers, organizations, or partners.

These providers create, manage, and maintain the underlying cloud infrastructure, platforms, or software and sell them to:

• External customers (businesses and developers)
• Internal departments (in the case of private or hybrid clouds)

Some organizations may act as internal cloud service providers, offering services exclusively to their employees, departments, or partners, either for operational efficiency or as a profit-generating division.

Cloud service providers also develop and deploy applications and services within cloud environments, enabling users to scale and manage their workloads on-demand.

Direct customers in a cloud ecosystem are users who directly interact with the services provided by a business hosted in a cloud environment.

These users access and utilize the applications, platforms, or services without needing to know whether those services are running on a public, private, or hybrid cloud infrastructure. For them, the focus is purely on the functionality and value of the service being offered.

Cloud Consumers are individuals, departments, or entire business units that use cloud services to perform specific tasks or operations.

These consumers interact with different types of cloud services—such as compute, storage, networking, or platform services—based on their needs. They do not manage or control the underlying cloud infrastructure but utilize its capabilities to fulfill business or technical goals.

Examples:

• A developer deploying applications using compute services on a public cloud.
• An analyst using cloud-based storage to access shared datasets.
• A business team using SaaS tools for collaboration and productivity.

In essence, a cloud consumer is any entity that leverages cloud services to achieve desired outcomes without worrying about the underlying infrastructure.

Cloud delivery models define the ways in which cloud computing resources and services are provided to users. The main models are:

• Infrastructure as a Service (IaaS) – On-demand delivery of servers, storage, networks, and operating systems. Users manage applications and OS, while the provider manages infrastructure.
• Platform as a Service (PaaS) – Combines IaaS with middleware, development tools, and deployment frameworks to help developers build, test, and deploy apps quickly.
• Software as a Service (SaaS) – Ready-to-use software applications delivered over the internet in a multi-tenant model.
• Function as a Service (FaaS) – Serverless model where developers deploy individual functions, and the cloud provider manages execution and scaling.

Cloud deployment models describe where and how the cloud infrastructure is hosted:

• Public Cloud – Infrastructure owned and operated by third-party providers for public use.
• Private Cloud – Exclusive resources owned and managed by a single organization for internal use.
• Hybrid Cloud – Combination of public and private clouds for flexibility and workload distribution.

• Cloud Consumers – Individuals or groups using cloud services to complete tasks.
• Direct Customers – End-users of your cloud-based products/services, unaware of the underlying infrastructure type.
• Cloud Service Providers – Companies that build and offer cloud service capabilities to customers.

Common storage levels in the cloud include:

• Files – Traditional file storage with hierarchical directories.
• Blocks – Raw storage volumes optimized for high-performance workloads.
• Datasets – Structured collections of related data for analytics.
• Objects – Data stored with metadata in flat address space, ideal for unstructured data.

Effective cloud cost management strategies include:

• Tracking and optimizing resource utilization to reduce waste.
• Using reserved instances for predictable workloads.
• Rightsizing instances to match actual usage.
• Implementing auto-scaling to adjust resources based on demand.

Serverless computing is a cloud model where the provider manages servers and infrastructure, allowing developers to focus solely on code. The system automatically handles scaling, availability, and maintenance.

Advantages:

• Cost-effective
• Simplified operations
• Increased developer productivity
• Highly scalable

Disadvantages:

• Potential latency in response
• Not suitable for high-compute workloads
• Security limitations
• Challenging debugging process

A monitoring agent is an event-driven service running alongside cloud workloads. It observes and analyzes dataflows, measures network traffic, and collects message metrics for performance and security insights.

On-demand functionality in cloud computing refers to the ability to access and use virtualized IT resources whenever required by the subscriber. These resources are delivered via a shared pool of configurable computing resources, which may include:

• Networks
• Servers
• Storage
• Applications
• Services

This model ensures flexibility, scalability, and cost efficiency since resources are allocated only when needed.

Containers as a Service (CaaS) is a cloud service model that enables users to manage containers, applications, and clusters through APIs, web portals, or automation tools. CaaS allows:

• Uploading, editing, starting, stopping, and rating containers
• Deployment in local or cloud data centers
• Secure, isolated, and scalable application environments

CaaS combines the benefits of containerization with cloud scalability, making it ideal for microservices and distributed applications.

A containerized data center is a pre-fabricated, portable data center built inside a shipping container. It houses essential IT and infrastructure equipment, such as:

• Servers and storage devices
• Networking gear
• UPS systems and generators
• Cooling units

These units have built-in connections for power, cooling, and data, making them quick to deploy and scalable for on-site or remote operations.

Mobile Cloud Computing (MCC) integrates mobile computing, cloud computing, and wireless networks to deliver computational resources to mobile users, network operators, and cloud providers. MCC allows:

• Running rich mobile applications across diverse devices
• Data storage and processing outside the mobile device
• Improved scalability and flexibility for mobile services

A hypervisor, or Virtual Machine Monitor (VMM), is a virtualization layer that enables multiple guest operating systems to run on a single physical host. It manages resource allocation, isolation, and partitioning. Types include:

• Type 1 (Bare Metal) – Runs directly on hardware (e.g., VMware ESXi, Microsoft Hyper-V)
• Type 2 (Hosted) – Runs on a host OS (e.g., VirtualBox, VMware Workstation)

Virtualization is the process of creating virtual versions of computing resources (e.g., servers, storage, networks) instead of using the physical versions directly. It allows for:

• Efficient resource utilization
• Isolation between workloads
• Flexibility in deployment and scaling

Initially developed in the mainframe era, virtualization now underpins modern cloud computing infrastructure.