AWS Interview Questions and Answers – EC2 , VPC , S3 and Network and Security.

Describe, What is EC2 instance ?

An EC2 instance is a virtual server in Amazon’s Elastic Compute Cloud (EC2) for running applications on the Amazon Web Services (AWS) infrastructure.

Describe, what is S3 ?

S3 stands for Simple Storage Service.  You can think of it like FTP storage, where you can move files to and from there, but not mount it like a file system.  AWS automatically puts your snapshots there. Encryption should be considered for sensitive data, as AWS S3 is a proprietary technology developed by Amazon.

Describe, what is T2 instances ?

T2 instances are designed to provide moderate baseline performance and the capability to burst to higher performance as required by workload.

Describe, What is Amazon EC2 service ?

Amazon describes Elastic Compute Cloud (Amazon EC2) as a web service that provides resizable compute capacity in the cloud. It is designed to make web-scale cloud computing easier for developers. Amazon EC2’s simple web service interface allows developers to obtain and configure capacity with minimal friction.

Describe, What is auto-scaling?  How does it work ?

Auto-scaling is a feature of AWS which allows you to configure and automatically provision and spin-up new instances without the need for your intervention.

Describe, What is VPC ?

Amazon Virtual Private Cloud (Amazon VPC) enables you to launch (AWS) Amazon Web Services resources into a virtual network that you’ve defined. This virtual network closely resembles a traditional network that you’d operate in your own data center, with the benefits of using the scalable infrastructure of AWS. A virtual private cloud (VPC) is an on-demand configurable pool of shared computing resources allocated within a public cloud environment, providing a certain level of isolation between the different organizations (denoted as users hereafter) using the resources.

Describe, What are the different types of cloud services ?

SAAS – Software as a Service
DAAS – Data as a Service.
PAAS – Platform as a Service.
IAAS – Infrastructure as a Service

Describe, What is Openswan ?

Openswan is an Open Source implementation of ipsec for the Linux OS.IPsec implementation in Linux for creating a tunnel between two private networks through the internet.

Describe, What is Amazon EC2 Security Groups ?

A security group acts as a virtual firewall that controls the traffic for one or more instances. When you launch an instance, you associate one or more security groups with the instance. You add rules to each security group that allow traffic to or from its associated instances. Security groups act as a firewall for associated instances, controlling both inbound and outbound traffic at the instance level.

Describe, What is the difference between Scalability and Elasticity ?

Scalability is a characteristic of cloud computing through which increasing workload can be handled by increasing in proportion the amount of resource capacity. It allows the architecture to provide on demand resources if the requirement is being raised by the traffic.

Elasticity is being one of the characteristic provide the concept of commissioning and decommissioning of large amount of resource capacity dynamically. It is measured by the speed by which the resources are coming on demand and the usage of the resources.

Describe, How to use Amazon SQS ?

Amazon SQS is a message passing mechanism that is used for communication between different connectors that are connected with each other. It also acts as a communicator between various components of Amazon. It keeps all the different functional components together. This functionality helps different components to be loosely coupled, and provide an architecture that is more failure resilient system.

Describe, What is Amazon Machine Image (AMI) ?

An Amazon Machine Image (AMI) is a template that contains a software configuration (for example, an operating system, an application server, and applications). From an AMI, we launch an instance, which is a copy of the AMI running as a virtual server in the cloud. We can launch multiple instances of an AMI.

Describe, What is the relation between Instance and AMI ?

An Amazon Machine Image (AMI) is a template that contains a software configuration (for example, an operating system, an application server, and applications).We can launch different types of instances from a single AMI.

An instance is a virtual server in Amazon’s Elastic Compute Cloud (EC2) for running applications on the Amazon Web Services (AWS) infrastructure. Each instance type offers different compute and memory capabilities. After we launch an instance, it looks like a traditional host and have complete control of our instances.

Describe, What Is Amazon Glacier?

Amazon Glacier is a storage service optimized for infrequently used data or Cold data.
Amazon Glacier service is an extremely low-price storage service that provides robust storage with security features for data archiving and backup. With Amazon Glacier, customers can store their data cost effectively for months, years, or even decades.

Describe, Network address translation (NAT) ?

NAT is a method of remapping one IP address space into another by modifying network address information in Internet Protocol (IP) datagram packet headers while they are in transit across a traffic routing device.

Describe,  What are Elastic IP addresses ?

An Elastic IP address is a static ipv4 address designed for dynamic cloud computing. An Elastic IP address is associated with your AWS account. An Elastic IP address is a reserved public IP address that you can assign to any EC2 instance in a particular region, until you choose to release it.

Describe, What is AMI and the relation between Instance and AMI ?

Amazon Web Services provides several ways to access Amazon EC2, like web-based interface, AWS Command Line Interface (CLI) and Amazon Tools for Windows PowerShell. First you need to signed up for an AWS account and you can access Amazon EC2. Amazon EC2 provides a Query API. These requests are HTTP or HTTPS requests that use the HTTP verbs GET or POST and a Query parameter named Action.

Describe, What is Amazon EC2 Root Device Volume ?

When you launch an instance, the Root Device Volume contains the image used to boot the instance.

You can launch an instance from one of two types of amis:

1. Instance store-backed AMI
2. EBS based storage

Describe, Route 53 ?

Amazon Route 53 (Route 53) is a scalable and highly available Domain Name System (DNS). The name is a reference to TCP or UDP port 53, where DNS server requests are addressed.

Describe, What Is Auto-scaling? How Does It Work ?

Auto scaling is a feature of AWS which allows you to configure and automatically provision and spin up new instances without the need for your intervention. Auto Scaling helps you maintain application availability and allows you to dynamically scale your Amazon EC2 capacity up or down automatically according to conditions you define.

Describe, What is VPC VPN ?

By default, instances that you launch into a virtual private cloud (VPC) can’t communicate with your own network. You can enable access to your network from your VPC by attaching a virtual private gateway to the VPC, creating a custom route table, updating your security group rules, and creating an AWS managed VPN connection.
Although the term VPN connection is a general term, in the Amazon VPC documentation, a VPN connection refers to the connection between your VPC and your own network. AWS supports Internet Protocol security (ipsec) VPN connections.

What is AWS CloudWatch ?

AWS CloudWatch is a cloud integrated monitoring tool used to monitor cloud computing resources like AWS Database services , EC2 instances , VPC components and users custom application and services.CloudWatch help to gain activity logs and resource visibility like resource and application utilisation, performance and operational health.You Can use CloudWatch to collect and monitor the logs , set alarms for the change management in your AWS resources.