1. Explain the difference between horizontal and vertical scaling in AWS.

Horizontal scaling involves adding more machines or instances to distribute the workload across multiple resources. It allows for better scalability and fault tolerance. Vertical scaling, on the other hand, involves increasing the resources (such as CPU or RAM) of a single machine to handle a larger workload.

2. How does Amazon S3 differ from EBS (Elastic Block Store)?

Amazon S3 (Simple Storage Service) is a scalable object storage service used for storing and retrieving large amounts of unstructured data. It is highly durable and designed for 99.999999999% durability. In contrast, Amazon EBS (Elastic Block Store) provides persistent block-level storage volumes for use with Amazon EC2 instances. It is often used for database storage or boot volumes.

3. What is the significance of Availability Zones in AWS?

Availability Zones (AZs) are geographically separate data centers within a region. They are designed to provide fault tolerance and high availability by ensuring that applications and data are replicated across multiple AZs. Each AZ operates independently with its power, networking, and cooling infrastructure.

4. How do you secure data in an S3 bucket?

To secure data in an S3 bucket, you can implement various measures. These include configuring access control through IAM policies and bucket policies, using server-side encryption to protect data at rest, and enabling versioning and logging for auditing purposes. You can also restrict access to specific IP addresses or VPC endpoints, and use AWS Identity and Access Management (IAM) roles to control access to the bucket.

5. Describe the difference between Auto Scaling and Load Balancing in AWS.

Auto Scaling is a feature in AWS that automatically adjusts the number of instances based on demand. It helps maintain application availability, optimize costs, and automatically scales resources up or down. Load balancing, on the other hand, distributes incoming traffic across multiple resources (such as EC2 instances) to ensure optimal performance and availability.

6. You are running a web application on Amazon EC2 instances. The application experiences high traffic during certain periods of the day. On average, each EC2 instance can handle 100 requests per second. During peak times, you expect to receive 10,000 requests per second. How many instances should you provision to handle the peak traffic?

To handle the peak traffic of 10,000 requests per second, divide the peak traffic by the capacity per instance: 10,000 requests per second / 100 requests per second per instance = 100 instances. Therefore, you should provision 100 instances to handle the peak traffic.

7. Explain the concept of VPC (Virtual Private Cloud) in AWS.

A Virtual Private Cloud (VPC) is a logically isolated network within the AWS cloud. It allows you to define a virtual network topology, configure IP addresses, subnets, route tables, and security settings. VPCs provide enhanced security, control, and flexibility for deploying AWS resources.

8. How does AWS Lambda work?

AWS Lambda is a serverless computing service that allows you to run code without provisioning or managing servers. It automatically scales based on the incoming request volume, and you pay only for the compute time consumed by your code. Lambda supports various programming languages and can be triggered by events from other AWS services.

9. How do you monitor AWS resources and applications?

AWS provides several services for monitoring resources and applications. Amazon CloudWatch is a monitoring service that collects and tracks metrics, logs, and events. It helps you gain insights into resource utilization, application performance, and operational health. You can set alarms, create dashboards, and automatically respond to events using CloudWatch.

10.What are the best practices for optimizing cost in AWS?

To optimize cost in AWS, you can follow several best practices. These include rightsizing instances by selecting the right instance type and size based on workload requirements, using reserved instances or savings plans for long-term workloads, leveraging auto scaling to dynamically adjust resources based on demand, and using cost allocation tags to track and manage costs. Additionally, regularly monitoring and analyzing your AWS Cost and Usage Reports can help identify cost optimization opportunities.