AWS Interview Questions: From Beginner to Advanced — Part 1

1. What is AWS?

Amazon Web Services (AWS) is a comprehensive and widely adopted cloud platform offered by Amazon. It provides a range of cloud services such as computing power, storage options, and networking capabilities. AWS enables businesses and developers to deploy, manage, and scale applications without the need for physical hardware.

2. What are the key services provided by AWS?

AWS offers numerous services categorized into different domains. Some of the key services include:

• Compute: Amazon EC2, AWS Lambda
• Storage: Amazon S3, Amazon EBS
• Databases: Amazon RDS, Amazon DynamoDB
• Networking: Amazon VPC, Amazon Route 53
• Analytics: Amazon EMR, Amazon Redshift

3. What is an EC2 instance?

Amazon EC2 (Elastic Compute Cloud) is a web service that provides secure, resizable compute capacity in the cloud. An EC2 instance is a virtual server in Amazon’s Elastic Compute Cloud (EC2) for running applications on the AWS infrastructure.

4. How do you launch an EC2 instance?

To launch an EC2 instance:

1. Open the Amazon EC2 console.
2. Click “Launch Instance.”
3. Choose an Amazon Machine Image (AMI).
4. Select an instance type based on your requirements.
5. Configure instance details, such as the number of instances and network settings.
6. Add storage by specifying the size and type of the volume.
7. Configure security groups to control inbound and outbound traffic.
8. Review and launch the instance.
9. Create or select an existing key pair for SSH access.

5. What is S3 in AWS?

Amazon S3 (Simple Storage Service) is a scalable object storage service that allows users to store and retrieve any amount of data at any time from anywhere on the web. It is designed for 99.999999999% (11 nines) durability.

6. Explain the difference between S3 and EBS.

• S3 (Simple Storage Service): Object storage service, used for storing and retrieving any amount of data. It is highly durable and accessible over the internet.
• EBS (Elastic Block Store): Block storage service, used as storage volumes for EC2 instances. It provides persistent storage that can be attached to EC2 instances.

7. What is an AMI?

An Amazon Machine Image (AMI) is a pre-configured template for an EC2 instance that contains the information required to launch an instance. This includes the operating system, application server, and applications.

8. What is the difference between stopping and terminating an EC2 instance?

• Stopping an EC2 instance: The instance is shut down, and you will not be billed for hourly usage, but the instance’s EBS volume remains and you can restart the instance later.
• Terminating an EC2 instance: The instance is permanently deleted, and all associated storage (EBS volumes) is also deleted unless specified otherwise.

9. What is a VPC?

A Virtual Private Cloud (VPC) allows you to provision a logically isolated section of the AWS cloud where you can launch AWS resources in a virtual network defined by you. You have complete control over your virtual networking environment.

10. What are the benefits of using AWS?

• Scalability: Easily scale resources up or down as needed.
• Cost-effective: Pay only for the resources you use.
• Security: Offers robust security features and compliance certifications.
• Flexibility: Wide range of services and tools to build and manage applications.
• Global Reach: Availability zones in multiple regions worldwide.

11. What is the difference between public and private subnets?

• Public Subnet: A subnet that is associated with a route table that has a route to an internet gateway. Resources in a public subnet can communicate with the internet.
• Private Subnet: A subnet that does not have a route to an internet gateway. Resources in a private subnet cannot communicate directly with the internet.

12. What is IAM?

AWS Identity and Access Management (IAM) is a service that helps you securely control access to AWS services and resources. It allows you to create and manage AWS users and groups, and to set permissions to allow or deny their access to AWS resources.

13. How do you secure data in S3?

To secure data in S3, you can:

• Enable server-side encryption: Encrypt data at rest.
• Use IAM policies: Control access to your S3 resources.
• Enable S3 bucket policies: Define rules to grant or deny access to buckets.
• Enable versioning: Preserve, retrieve, and restore every version of every object in an S3 bucket.
• Enable MFA delete: Add another layer of security for object deletion.

14. What is the purpose of AWS CloudFormation?

AWS CloudFormation provides a way to model and set up your AWS resources using a template file. It allows you to define the infrastructure as code, which helps automate the deployment and management of AWS resources.

15. What is AWS Lambda?

AWS Lambda is a serverless compute service that allows you to run code without provisioning or managing servers. You can run your code in response to events, such as changes to data in an S3 bucket or an update to a DynamoDB table.

Example: Launching an EC2 Instance

Let’s launch an EC2 instance step by step:

1. Open the Amazon EC2 Console: Navigate to the EC2 dashboard.
2. Click “Launch Instance”: Start the instance creation process.
3. Choose an AMI: Select an Amazon Linux 2 AMI (HVM) — Kernel 5.10.
4. Select an Instance Type: Choose the “t2.micro” instance type (eligible for the free tier).
5. Configure Instance Details: Set the number of instances to 1. Ensure the default VPC is selected.
6. Add Storage: Use the default storage settings (8 GiB EBS volume).
7. Configure Security Groups: Create a new security group with an SSH rule allowing traffic from your IP address.
8. Review and Launch: Review the settings and click “Launch”.
9. Select a Key Pair: Create a new key pair or use an existing one, then click “Launch Instances”.

After a few minutes, your EC2 instance will be up and running, and you can connect to it using the SSH key pair.

This article covers the basics of AWS, key services, and some fundamental concepts. In subsequent parts, we will delve deeper into more advanced topics and questions.

Ready to dive deeper into AWS? Check out the next parts of our series to further enhance your AWS knowledge and prepare for your interviews:

• AWS Interview Questions: Intermediate Level — Part 2: Explore more advanced concepts, including Auto Scaling, Elastic Load Balancing, and Amazon RDS.
• AWS Interview Questions: Advanced Level — Part 3: Master the most complex topics such as AWS Direct Connect, serverless architecture, and disaster recovery strategies.