Public cloud computing is a service that can be accessed over the internet. It provides resources, on a shared basis, for hosting applications and data on distributed computing resources. Cloud providers host a pool of services for computer servers, storages, networks, application platforms and software services that are assigned to customers based on their needs. Cloud providers take responsibility of managing computing resources so that customers can concentrate on building applications or services quickly. AWS is the biggest public cloud service provider.

AWS provides most of the networking services that we are going to explore for free. It also lets customers experiment with some of the other services for free at a lower scale. We need to have an account and the required permissions in AWS to execute the recipes provided throughout this book. Creating some of the services may cost some money, so please look into the AWS pricing page (https://aws.amazon.com/pricing/services/) for different services and understand the cost impact that execution of some recipes will have.

In this section, we shall come to understand the building blocks of AWS Cloud. We are going to use or create the following components through this book.

• Region: AWS Cloud currently has data centers in 16 cities and is also coming up in new locations throughout the world. Each region is completely isolated from the others. You need to choose one region to create network components.
• Availability Zone (AZ): Each region of AWS Cloud has multiple physically isolated and separate data centers called availability zone. Some network components span across multiple AZs in a region like VPC. Components like subnet are confined within an AZ. AWS provides various networking services as Platform as a Service (PaaS). Examples are:
  • Route 53: Distributed, scalable and highly available Domain Name System (DNS)
  • Direct connect: This provides a dedicated low latency and high bandwidth network connectivity between a data center and an AWS VPC.
  • ELB: This is a high availablility and scalable load balancing service provided by AWS.
  • AWS VPC: VPC is a virtual network built in the AWS Cloud similar to a network in a data center. It is isolated from other VPCs that are created in your account or other accounts. You can choose the Classless Inter-Domain Routing (CIDR) range of the VPC and can create instances with the IP address within that range. Virtual Routing and Forwarding (VRF) in conventional networking is equivalent to a VPC in AWS, whereas VLAN is synonymous to a subnet. You can isolate instances in separate VLANs or subnets.

The following figure gives the default VPC components which include Internet gateway, Virtual private gateway, Router, Route table, Subnet, Network ACL and Security group.

Source: http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/images/security-diagram.png

We are going to create an AWS account in this section. Please skip this section if you already have an AWS account. Otherwise, please follow the step by step process to create an account with AWS.

Be ready with your credit card information.

1. Please open the URL https://aws.amazon.com/account/ in your favorite browser.
2. Click on the button Create an AWS Account.
3. You will see a page which looks like the following figure. Provide your email or mobile number, select the option I am a new user and click on Sign in using our secure server. The email ID provided here will be treated as the owner or root user for this account and has exclusive rights to do anything in the account.

4. You will get a page like this. Provide the required details and click on Create account.

5. Provide additional details for your account.

6. Provide payment information for billing purposes.

7. Provide identity verification. There will be an automated call initiated by AWS to your phone number and you will need to key in the verification code shown on the screen.

8. Choose Support Plan and click on Continue.

9. You will see a welcome screen and can log in to the AWS console by clicking on Sign In to the Console. You'll also receive an email confirmation for the account creation.

10. After login, you will see a screen like the following:

Once you decide to delete your account, you can do so by logging in to your account; see the following figure:

Once the account is created, we should not use it for anything apart from creating an admin user and handling billing related information. A strong password policy and multi-factor authentication (MFA) should be configured for all powerful users. We shall go through the steps to create an admin user. We shall use this user credential for executing recipes for different network elements in AWS. More stringent processes and methods should be followed for creating and managing users in AWS for production purposes.

Log in to the AWS account with user credentials.

1. Select Identity and Access Management (IAM) service from the console by typing https://console.aws.amazon.com/iam/ in the browser. You will see the URL that the user other than the root user will need to use for console access.

2. Click on Users in the left menu and then click on Add user.

3. Provide a username of your choice. Opt for both programmatic and console access. Select other relevant options and click on Next: Permission.

4. Choose the option Attach existing policies directly. Choose AdministratorAccess and then click Next: Review.

5. Review the details and click on Create User.

6. Download and store the .csv file in a safe place. The file contains user access key details and console login link. User access information is required for AWS service access through program or CLI. It will be used in the later part of the book.

The user access details can be used for accessing AWS from Command Line Interface (CLI). Scripts can be written using CLI and can be used as code for managing AWS infrastructure.