Cloud computing is an on-demand computing resource that provides multi-tenant or dedicated computing resources, such as compute, storage, and network, which are delivered to users over the network.

A network in the form of internet or LAN is based on the deployment model of the cloud. According to NIST's definition of cloud computing, it has both cloud deployment models and cloud service models:

Cloud deployment models define the way resources are deployed, that is, whether they are accessible over LAN or accessible over the internet. There are four cloud deployment models:

• Public cloud, which is accessible over the internet
• Private cloud, which is accessible over LAN and owned by an organization
• Community cloud, where resources are shared by a specific set of organizations that share similar types of interests
• Hybrid cloud, which combines two or more deployment models to form a cloud based on specific use cases such as databases that are on-premise due to security reasons

The cloud service model defines the way cloud resources are used by taking into consideration their flexibility or the options that are provided to users. There are three cloud service models:

• Infrastructure as a Service (IaaS): Resources such as compute, storage, and network are accessible to users. Security and control is in the hands of users. The cloud service provider plays a limited role in resource management in this service model.
• Platform as a Service (PaaS): Users get a platform where he/she can deploy a package directly without worrying about setting up a runtime environment. Security and control is in the hands of the cloud service provider. Users can do some configuration for versions of the web server, enable logs, set up load balancers, and so on. Users play a limited role in resource management in this service model.
• Software as a Service (SaaS): The user creates an account, and all of the services are available directly. Office 365, Google Docs, and Zoho Docs are some popular examples of SaaS. The cloud service provider is responsible for resource management in this service model.

Cloud computing has a few characteristics that are significant, such as the multi-tenancy, pay as you go billing model that is similar to electricity billing; an on-demand self service; resource pooling for better utilization of cloud resources; rapid elasticity for scaling up and scaling down instances that are served in case of IaaS or PaaS based on needs in an automated manner; and measured services for billing.

There are many cloud service providers that provide public cloud services in the market. However, among all the providers, Amazon Web Services (AWS) has established itself as a leader in terms of innovation and the services it provides.

This all began in 2006 when AWS started providing infrastructure services.

Now, AWS services are utilized in more than 190 countries all over the world, and many research firms have announced AWS as a leader in the cloud space as well.

The AWS Cloud operates in 16 geographic Regions, with 44 Availability Zones around the world. Some of these are depicted in the following diagram:

A Region is a location in any part of the world, whereas Availability Zones (AZs) are separate data centers that are available in a specific region:

Each region is isolated from another region, and each Availability Zone is planned as an independent failure zone to support highly available resources, fault-tolerant resources, and scalable application architecture.

Security in AWS is a shared responsibility based on the cloud service model that's used by the customer or user. In AWS, physical resources, such as servers, storage, and the network, are managed by AWS. Users don't have to worry about security since AWS has already put in best practices and it is transparent.

It is up to you to configure security in AWS as per the proven best practices that are available for the AWS infrastructure.

Users can configure security groups and access control lists, Virtual Private Cloud (VPC), and identity and access management to make the resources in the cloud more secure:

Compliance is extremely important for the assurance of security and protection. Security and compliance are both shared responsibilities for AWS and the AWS customer, and is based on how much the cloud service model is used by the customer. AWS complies to SOC 1/ISAE 3402, SOC 2, SOC 3, FISMA, DIACAP, FedRAMP, PCI DSS Level 1, ISO 9001, ISO 27001, ISO 27018, and so on.

Amazon Elastic Compute Cloud (EC2) is a web service. Do you remember Amazon Web Services?

Amazon EC2 provides compute services in the Amazon Cloud.

Is it easy to get your hands on it?

Yes; you can create an account and use the free tier to create a simple instance:

You need to follow these steps to create an instance:

1. Go to aws.amazon.com and log in with your credentials.
2. Click on Services in the top bar:

3. Select EC2 from the Compute services that are available in the AWS Portal.
4. The Amazon EC2 dashboard provides details related to a number of running instances, such as Elastic IPs, Volumes, Key Pairs, Snapshots, Load Balancers, Security Groups, Service Health, Supported Platforms, Default VPC-related information, and so on:

5. Click on the Launch instance and follow the simple wizard to create an instance.
6. After you have created an instance, the EC2 dashboard will give complete details of your Amazon EC2 instance.
7. Click on Instances in the EC2 dashboard to get details on all the instances that you have created in Amazon EC2:

You can edit instance configuration, restart an instance, or terminate an instance from the Action menu, which can be found in the EC2 dashboard.

Instances come in different types, and are based on usage and pricing: