Interview questions on High availability and disaster recovery

1. What is high availability in AWS?

High availability in AWS refers to the ability of a system to continue functioning and provide service even if one or more components fail. AWS provides various services such as Amazon EC2 Auto Scaling, Amazon Route 53, and Amazon ELB to ensure high availability for applications.

2. What is disaster recovery in AWS?

Disaster recovery in AWS refers to the ability to restore an application or system to a known good state in the event of an unexpected outage or disaster. AWS provides services such as Amazon S3, Amazon Glacier, and AWS Backup to help customers implement disaster recovery solutions.

3. How can you implement high availability for an EC2 instance?

High availability for an EC2 instance can be achieved by using Amazon EC2 Auto Scaling and Amazon ELB. EC2 Auto Scaling can automatically scale the number of instances in an Auto Scaling group based on demand, while ELB can distribute incoming traffic across multiple instances to ensure that your application is always available.

4. How can you implement disaster recovery for an RDS database?

Disaster recovery for an RDS database can be achieved by using Amazon RDS Multi-AZ deployments. In a Multi-AZ deployment, RDS automatically synchronizes data between a primary and secondary instance, and in the event of a failure, RDS automatically switches over to the secondary instance to ensure that your database remains available.

5. What are the benefits of using AWS for high availability and disaster recovery?

The benefits of using AWS for high availability and disaster recovery include:

• Scalability and flexibility to easily accommodate changing demands
• Automated processes to reduce manual intervention and human error
• Cost-effective solutions to ensure availability without sacrificing cost
• A wide range of services to meet a variety of requirements and disaster scenarios.

6. How does Amazon S3 provide data durability?

Amazon S3 provides data durability through its “Eleven 9s” durability guarantee, which means that S3 stores multiple copies of data across multiple devices in multiple facilities, and is designed to withstand the loss of two facilities simultaneously. This ensures that customer data is always available and protected, even in the event of a disaster.

7. How does Amazon Route 53 provide high availability for DNS?

Amazon Route 53 provides high availability for DNS by using multiple servers in multiple geographic locations to respond to DNS queries. Route 53 also automatically detects and routes around failures, ensuring that your DNS queries are always answered, even if one or more servers are unavailable.

8. How does Amazon CloudFront provide high availability for content delivery?

Amazon CloudFront provides high availability for content delivery by storing multiple copies of content at edge locations around the world. When a user requests content, CloudFront automatically routes the request to the nearest edge location, ensuring low latency and fast delivery of content. In the event of a failure, CloudFront automatically routes requests to another edge location, ensuring that content is always available.

9. How can you implement disaster recovery for an EC2 instance?

Disaster recovery for an EC2 instance can be achieved by creating an Amazon Machine Image (AMI) of the instance and storing it in Amazon S3, and then using the AMI to launch a new instance in a different Availability Zone or Region in the event of a disaster. Another option is to use Amazon EC2 Auto Scaling and Amazon ELB to automatically launch replacement instances in another Availability Zone or Region in the event of a failure.

10. Can you explain the difference between multi-AZ and single-AZ RDS deployments?

In a single-AZ RDS deployment, the database runs on a single Amazon EC2 instance in a single Availability Zone. In a multi-AZ RDS deployment, the database runs on multiple Amazon EC2 instances in multiple Availability Zones. In the event of an Availability Zone failure, multi-AZ deployments automatically failover to a different Availability Zone to ensure high availability and minimize downtime. Single-AZ deployments do not have this capability, and therefore are not recommended for production workloads that require high availability.

11. How can you backup data in AWS?

Data can be backed up in AWS by using AWS Backup, a fully managed backup service. AWS Backup enables you to centralize and automate backup of your data stored in AWS services such as Amazon EBS volumes, Amazon RDS databases, Amazon DynamoDB tables, and Amazon S3 buckets. Additionally, data can also be backed up to Amazon S3 or Amazon Glacier for long-term storage and archiving.

12. What is Amazon S3 Transfer Acceleration?

Amazon S3 Transfer Acceleration is a feature that enables fast, easy, and secure transfers of large files over long distances to Amazon S3. Transfer Acceleration uses Amazon CloudFront’s globally distributed edge locations to accelerate uploads over the public internet. By using S3 Transfer Acceleration, customers can upload large files to S3 up to six times faster than using traditional methods.

13. What is Amazon Elastic Block Store (EBS)?

Amazon Elastic Block Store (EBS) is a block-level storage service for use with Amazon EC2 instances. EBS provides persistent storage for data that requires frequent and low-latency access, such as databases and file systems. EBS offers multiple performance and storage options to support a wide range of use cases.

14. What is Amazon EC2 Auto Scaling?

Amazon EC2 Auto Scaling is a service that automatically increases or decreases the number of Amazon EC2 instances in a group based on demand, without manual intervention. EC2 Auto Scaling helps ensure that your application always has the required capacity to handle incoming traffic and maintain performance.

15. What is Amazon Virtual Private Cloud (VPC)?

Amazon Virtual Private Cloud (VPC) is a virtual network dedicated to your AWS account. VPC enables you to launch AWS resources into a virtual network that you’ve defined. You have complete control over your virtual networking environment, including the selection of your own IP address range, creation of subnets, and configuration of route tables and network gateways.

16. What is Amazon CloudWatch?

Amazon CloudWatch is a monitoring service for AWS resources and the applications you run on the Amazon Web Services (AWS) cloud. CloudWatch provides operational visibility and insights for instances, applications, and resources, enabling you to monitor performance, troubleshoot issues, and ensure availability.

17. What is Amazon Simple Queue Service (SQS)?

Amazon Simple Queue Service (SQS) is a fully managed message queuing service that enables decoupled communication between distributed software systems. SQS provides a reliable, highly scalable, and low-latency message delivery system, allowing you to transmit any volume of data between systems, applications, and services.

18. What is Amazon Elastic Compute Cloud (EC2)?

Amazon Elastic Compute Cloud (EC2) is a web service that provides secure, resizable compute capacity in the cloud. EC2 makes it easy to launch, manage, and scale virtual machines, or instances, in the cloud, enabling you to build, deploy, and run applications in the cloud.

19. What is Amazon Relational Database Service (RDS)?

Amazon Relational Database Service (RDS) is a fully managed relational database service that makes it easy to set up, operate, and scale a relational database in the cloud. RDS supports multiple database engines, including Amazon Aurora, PostgreSQL, MySQL, MariaDB, Oracle Database, and Microsoft SQL Server.

20. What is Amazon DynamoDB?

Amazon DynamoDB is a fully managed NoSQL database service that provides fast and predictable performance with seamless scalability. DynamoDB enables you to store, retrieve, and manage large amounts of unstructured or semi-structured data, and offers fast, single-digit millisecond response times.

21. What is Amazon S3?

Amazon S3 (Simple Storage Service) is an object storage service that offers industry-leading scalability, data availability, security, and performance. This means customers of all sizes and industries can use it to store and protect any amount of data for a range of use cases, such as websites, mobile applications, backup and restore, archive, enterprise applications, IoT devices, and big data analytics.

22. What is Amazon Glacier?

Amazon Glacier is a low-cost, secure, and durable cloud-based archive storage service. Glacier provides a long-term and cost-effective solution for data archiving and backup, enabling you to store large amounts of data