Introduction: Mastering the Cloud Interview Landscape
There has never been a greater demand for cloud engineers, solutions architects, and DevOps experts in the world. With the move by companies from their on-premise data centers to multi-cloud environments, acing the cloud technical interview is no longer about knowing your way around definitions. Companies seek candidates with the right skills, knowledge, and experience.
In this exhaustive tutorial on cloud computing interview questions and answers, we cover some important questions to help you stand out in your interviews irrespective of whether you are a fresher or an experienced candidate. This tutorial includes relevant questions and detailed answers to help you perform well in your interviews with top technology companies, startups, and enterprise organizations.
Basic Interview Questions on Cloud Computing for Beginners
While starting out on the journey of a career in the cloud, you will be asked to demonstrate your understanding of basic concepts, cloud service delivery models, and technology used in cloud infrastructure.
+-----------------------------------+
| Client Layer / Frontend |
+-----------------+-----------------+
|
(Internet Gateway / API)
|
+-----------------v-----------------+
| Public Subnet (Application |
| Load Balancer) |
+-----------------+-----------------+
|
+------------------+------------------+
| |
+-----------v-----------+ +-----------v-----------+
| Private Subnet 1 | | Private Subnet 2 |
| (App Server / EC2) | | (App Server / EC2) |
+-----------+-----------+ +-----------+-----------+
+------------------+------------------+
|
+-----------------v-----------------+
| Database Subnet (Multi-AZ RDS) |
+-----------------------------------+
1. Definition of cloud computing and the key characteristics of cloud computing
Important Topic to Understand: What is cloud computing and its features?
Cloud computing is a technology that provides the computing capabilities like servers, storage, databases, networking, software, intelligence, etc., on demand via the internet to the users. Businesses have the option of leasing out their computing capabilities from cloud service providers like AWS, Microsoft Azure, GCP, etc via virtualization.
The five essential features of cloud computing as defined by NIST are:
- On-demand self-service: Computing resources are automatically provisioned by the user without any interaction with the cloud provider.
- Broad network access: Capabilities are broadly accessible over the network through standardized mechanisms (web interfaces, mobile interfaces, etc.)
- Resource pooling: Resources are pooled together from a large pool of computing resources of the cloud provider.
This is also referred to as “Transitory Flexibility” (TF).
2. How is IaaS unique from PaaS and SaaS?
IaaS vs. PaaS vs. SaaS | What are the Differences between IaaS, PaaS and SaaS?
Highlight of Topic: Infrastructure as a Service v/s Platform as a Service v/s Software as a Servic
It is imperative that the differences among the three be clearly understood by candidates who sit for a cloud computing interview questions and answers assessment. And this is because each of them has their individual level of control and shared responsibility:
- Quick Scalability: The capability to expand or contract as per the need.
Controlled Services: The capability of managing and controlling the usage of computing services.
2. How do IaaS, PaaS and SaaS differ from each other?
Topic Overview: IaaS, PaaS, and SaaS - IT Services Models
That is because each of these provides a different level of control and responsibility sharing as follows:
IaaS (Infrastructure as a Service): The basic infrastructure is provided here. All the control over the operating system, middleware, runtime and application can be obtained.
This category includes virtual computers such as Amazon EC2, Azure Virtual Machines and Google Compute Engine.
PaaS (Platform as a Service): The complete platform to create, test, run and manage applications.
As an example for PaaS there are AWS Elastic Beanstalk, Google App Engine and Azure App Service.
SaaS (Software as a Service): Complete software that customers use.
Examples: Google Workspace, Salesforce, Microsoft 365, Netflix.
3. Role of Virtualization in Cloud Computing
Highlight of the Topic: Significance of virtualization in cloud architecture
Virtualization technology plays an important part in making cloud computing a reality. Virtualization is achieved using software known as hypervisor, which helps in abstracting the layer of physical hardware, such as VMware ESXi, KVM, and Hyper-V. The physical hardware is then segmented to create many virtual machines (VM) running different operating systems in one physical machine.
Virtualization is a must-have technology without which the cloud cannot offer any features such as multi-tenancy, scalability, and provisioning.
4. Public, Private, Hybrid, and Multi-Cloud Deployment Models
Topic Concentration: Comparison of Cloud Deployment Models
Some key considerations for selecting a suitable deployment model are; security, compliance and cost.
Public Cloud: The public cloud computing environment, which is managed by third-party cloud service providers over the Internet to deliver maximum scalability and minimal initial investment.
Scale-Up: Add more cores, more memory or faster disks to the existing server to increase performance.
Private Cloud Infrastructure: The private cloud or on-premise cloud infrastructure is entirely owned by a company. The company can host it in their own data center or utilize cloud service providers to host it for them. The key advantages of private cloud computing are security and compliance with regulations.
Hybrid Cloud: A combination of a private or on-premise cloud and public cloud(s) with methods to connect between two including VPNs and dedicated connections like AWS Direct Connect or Azure ExpressRoute. Applications that require to be running on company premises can be scaled on the public cloud computing for other applications.
5. How does horizontal scaling differ from vertical scaling?
Topic Spotlight: Scaling Approaches in Cloud Computing
During the process of creating high availability solutions, scaling issues are usually raised during interviews:
Scale-Up: This refers to improving the performance of the current server by adding cores, memory, or fast storage. Though easy to apply, vertical scaling suffers from physical constraints and is a process that takes some down time.
Horizontal Scaling (Scaling Out): Scaling out refers to scaling up by adding more servers to handle increased traffic.
Intermediate Cloud Computing Interview Questions for Experienced Candidates
Mid-level roles will typically require candidates to have knowledge of technology such as the cloud, networking and serverless computing.
6. What is VPC, and why is it important?
Topic Highlight: Understanding VPC architecture
VPC stands for a virtual network that is logically isolated to your cloud account in the infrastructure provided by the cloud service provider. It offers precise control to engineers over IP address range, subnets, route tables, network gateways, and network access controls.
With the help of public subnets for exposing internet-based applications such as application load balancers and private subnets for backend sensitive resources such as microservice containers and databases, a VPC avoids exposure to any malicious traffic on the internet.
7. Explain serverless computing and its practical benefits
Area of Interest: Serverless computing and Microservice architecture
Serverless Computing (Function-as-a-Service - FaaS)
Serverless computing (Function-as-a-Service - FaaS) gives the developer the ability to upload his/her code and run it without any worries regarding any server-side configuration or set-up. All the aspects of capacity planning, server management, OS upgrades, and auto-scaling are taken care of by the cloud provider.
By making use of cloud services such as AWS Lambda, Azure Functions, and Google Cloud Functions, the code is automatically triggered by some event (like an HTTP request via API, changes to databases, and uploading objects to the object store).
Among other things, it has two significant benefits – no charges for the idling periods and auto-scaling.
8. What is the Cloud Shared Responsibility Model?
Topic Spotlight: Security Boundaries within the Shared Responsibility Model
Security responsibilities within the Shared Responsibility Model are distributed between the cloud provider and the customer as follows:
- Responsibility FOR the Cloud (Provider): The cloud provider takes care of physical data centers, host hardware, access to facilities, storage infrastructure, network edge sites, and low-level virtualization platforms.
- Responsibility IN the Cloud (Customer): The customer is accountable for guest operating system updates, secure coding of applications, data encryption (both at rest and in transit), firewall rule configuration, and configurations related to Identity and Access Management (IAM).
+-------------------------------------------------------------------+
| CUSTOMER RESPONSIBILITY ("In" the Cloud) |
| - Customer Data & Classification |
| - IAM Policies, User Access & MFA |
| - Operating System Configuration & Security Patching |
| - Network Firewall Rules, Security Groups, Security Control |
+-------------------------------------------------------------------+
| PROVIDER RESPONSIBILITY ("Of" the Cloud) |
| - Physical Infrastructure & Facilities (Data Centers) |
| - Hardware Maintenance, Hypervisors, Host OS |
| - Global Infrastructure (Regions, Availability Zones, Edge) |
+-------------------------------------------------------------------+
9. How does Object Storage differ from Block Storage and File Storage?
- Topic Highlight: Public cloud infrastructure storage types
The importance of grasping storage mechanisms cannot be ignored when addressing cloud computing interview questions and answers:
Block Storage: It is fast storage blocks with a filesystem provided (example AWS EBS, Azure Managed Disks). It is important to make the application tier instances stateless using caching memory (Redis, Memcached).
Database Tier (Reliable): Use managed relational DB service (RDS from AWS) with Multi-AZ auto replication and read replicas.
Object Storage: It is such kind of storage which is used for storing unstructured data (videos, images, backups), where objects have data, metadata, and globally unique ID (such as AWS S3, Google Cloud Storage)..
File Storage: Shared network file system used simultaneously by several virtual machines (for example AWS EFS, Azure Files).
10. Explain containers and Docker and their difference from virtual machines?
Key Topic Point: Containerization vs Traditional Virtual Machines
Whereas virtual machines abstract hardware layers, containerization abstracts the applications. Containers are a means of packaging together all the dependencies of an application, such as code, libraries, binaries, and other runtime information.
Unlike virtual machines that create guest operating systems for each virtual machine created, containers use the host kernel and, therefore, are more efficient to boot up within milliseconds as compared to minutes taken by VMs.
Advanced Cloud Architecture & Scenario-Based Interview Questions
The senior positions are very much involved with the resilience of systems, fault tolerance across multiple regions, automation, and cost optimization in enterprises.
11. How would you design a highly available and fault-tolerant architecture for web applications using the cloud?
Design Fault-Tolerant and High-Aliability Architecture
To design a highly available architecture, you can consider the following loosely coupled multi-tier architecture:
- Traffic Routing: To route the traffic to the healthy instances, you need a DNS routing service with health check options (AWS Route 53 or Azure Traffic Manager).
- Load Balancing: To distribute the client requests, you will need an Application Load Balancer configured across different Availability Zones (AZ).
- Application Tier (Stateless): Place the application instances in the private subnet with the help of an auto-scaling group. Ensure all instances in your application tier are stateless and use cached memory (Redis/Memcached).
- Database Tier (Reliability): Use a Managed Relational Database Service (such as AWS RDS) with Multi-AZ and read replicas.
- Static Media Cache: Serve the static media from the CDN with the help of Object Storage.
12. What are your strategies for Cloud Cost Optimization (FinOps)?
Theme/Topic: Cloud Cost Optimization and FinOps Best Practices
Continuous cost management of the cloud is done through monitoring, governance, and optimization of architecture:
- Resource Size Optimization: Optimize the resource size and storage performance based on their usage.
- Commitment-Based Pricing Model: Incorporate RIs and/or Savings Plans to help control your estimated workload and realize up to 70% savings as compared to on-demand pricing based on the price list.
- Spot Instances: Use the additional processing power of the cloud to process your fault-tolerant pipeline and batch jobs along with containerized workloads.
- Storage Objects Lifecycle Management: Store objects of your storage automatically when they become old and unused.
Shutdown of Non-Production Environment: Schedule a shutdown of your non-production environment.
13. What is special about Terraform?
Answer Points: IaC; Terraform
Infrastructure as code, also known as IAC, involves configuring the cloud infrastructure through machine-readable configuration files and not via manual configuration from the console.
Terraform happens to be one of the best available IaC tools that runs on any cloud and is declarative.
Terraform, by HashiCorp, is one of the best tools used for Infrastructure as Code (IaC) which is cloud agnostic and declarative in nature. It helps engineers define cloud resources in AWS, Azure, GCP, and Kubernetes using HashiCorp Configuration Language (HCL).
14. What are RPO and RTO in cloud disaster recovery planning?
Highlighted Topic: Definition of RPO and RTO for DR strategies
DR metrics outline business continuity approaches during cloud failures:
- RPO (Recovery Point Objective): Maximum tolerable level of data loss measured in time. Specifies data restoration point backward in time from the backup storage (e.g., a 15-minute RPO means that up to 15 minutes of transaction data can be lost).
- RTO (Recovery Time Objective): Maximum allowable outage period in case of an application downtime from the moment of incident to its resolution.
[Incident]
│
├─── Data Loss Period ────► [Previous Successful Backup] <- RPO
│
└─── Downtime Period ─────► [Successful Restoration] <- RTO
Popular cloud DR approaches include Backup & Restore, Pilot Light, Warm Standby, and Multi-Region Active-Active approaches based on RPO and RTO requirements.
15. What is Cloud Observability, and how do Logs, Metrics, and Traces differ?
Topic Highlight: Observability pillars of the cloud
Observability is a means of understanding the internal state of a complex, distributed cloud system using its external outputs:
- Metrics: Time-series numerical data (CPU utilization, HTTP errors, network performance).
- Logs: Textual data produced by services, OS, application code at particular moments in time regarding particular events.
- Traces: Path of execution of one user request through distributed microservices, pinpointing bottlenecks and latencies within API calls.
Frequently Asked Questions (FAQs)
Q1. How do I begin preparations for cloud computing interviews being an absolute beginner?
Learn the basics of cloud computing starting from the very beginning, i.e., learn the client-server model, virtualization, basics of networking (DNS, IP address, HTTP), and cloud computing services (IaaS, PaaS, SaaS). Open a free account in AWS, Azure, or Google Cloud Platform and try out creating virtual machines, setting up security groups, and deploying a basic web application.
Q2. Does one need to code to pursue a career in cloud computing?
Absolutely. Cloud computing requires knowledge of programming or scripting of any kind from basic to intermediate level. The engineer needs to code in Python, Bash, Go, PowerShell, etc., to automate tasks, integrate APIs, and Infrastructure as Code (IaC) with Terraform and Ansible.
Q3. What is the cloud provider with high job market demand?
Amazon Web Services (AWS) has the biggest market share when it comes to cloud infrastructure, then comes Microsoft Azure and Google Cloud Platform (GCP). AWS and Azure usually hold the biggest number of enterprise jobs, however, mastering the art of multi-cloud will make you a good candidate for all industries.
Q4. How does DevOps differ from Cloud Computing?
Cloud computing refers to on-demand delivery of computing hardware resources, storage, and network over the internet. DevOps is a culture and set of practices and technologies for automating and integrating development processes (Dev) and IT operations (Ops). Cloud infrastructure is used to create efficient DevOps pipeline (CI/CD).
Q5. What are the top cloud certifications that are most in demand?
The most popular and highly rated certifications include AWS Certified Solutions Architect (Associate/Professional), Microsoft Certified: Azure Solutions Architect Expert, Google Associate Cloud Engineer, Certified Kubernetes Administrator (CKA), and HashiCorp Certified: Terraform Associate.
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