Why do organisations move to the cloud? The traditional approach of buying and managing your own physical servers and infrastructure is expensive and slow. It involves large upfront capital expenditures, ongoing maintenance costs, and a constant cycle of predicting future capacity needs. Cloud computing, particularly with a provider like AWS, flips this model on its head.

Instead of owning your own computing infrastructure, you access it as a service over the internet. This shift offers significant advantages in cost, speed, and global reach.

When you migrate to the cloud, you gain several key business advantages. AWS defines these as the 'Six Advantages of Cloud Computing':

1. Trade capital expense for variable expense: Instead of investing heavily in data centres and servers before you know how you’re going to use them, you can pay only when you consume computing resources, and pay only for how much you consume.

2. Benefit from massive economies of scale: By using cloud computing, you can achieve a lower variable cost than you can get on your own. Because usage from hundreds of thousands of customers is aggregated in the cloud, providers like AWS can achieve higher economies of scale, which translates into lower pay-as-you-go prices.

3. Stop guessing capacity: Eliminate guessing on your infrastructure capacity needs. When you make a capacity decision prior to deploying an application, you often end up either sitting on expensive idle resources or dealing with limited capacity. With cloud computing, you can access as much or as little capacity as you need, and scale up and down as required with only a few minutes’ notice.

4. Increase speed and agility: In a cloud computing environment, new IT resources are only a click away, which means you reduce the time it takes to make those resources available to your developers from weeks to just minutes. This results in a dramatic increase in agility for the organisation, since the cost and time it takes to experiment and develop is significantly lower.

5. Stop spending money on 'undifferentiated heavy lifting': Focus on projects that differentiate your business, not the infrastructure. Cloud computing lets you focus on your own customers, rather than on the heavy lifting of racking, stacking, and powering servers.

6. Go global in minutes: Easily deploy your application in multiple regions around the world with just a few clicks. This means you can provide lower latency and a better experience for your customers at minimal cost.

Migrating to the cloud isn't just a technical shift; it's a fundamental change in how a business operates. To help organisations manage this transition, AWS created the Cloud Adoption Framework (CAF). The CAF provides guidance and best practices to help organisations build a comprehensive approach to cloud computing across the business, not just within the IT department.

The framework is organized into six perspectives, each focusing on a specific area of the business. The Business, People, and Governance perspectives focus on business capabilities, while the Platform, Security, and Operations perspectives focus on technical capabilities. By considering all six, an organisation can ensure a smooth and successful cloud adoption journey.

One of the most critical concepts to understand in cloud computing is the Shared Responsibility Model This model defines what you, as the customer, are responsible for, and what AWS is responsible for. It's a fundamental shift from a traditional on-premises data centre, where you are responsible for everything from physical security to application code.

At its simplest, AWS is responsible for the security of the cloud, while you, the customer, are responsible for security in the cloud.

AWS's Responsibility: Security OF the Cloud

AWS manages and controls the components from the host operating system and virtualization layer down to the physical security of the facilities in which the services operate. This includes:

• Hardware: The physical servers, storage devices, and networking equipment.
• Software: The foundational software that runs the cloud services, such as compute, storage, database, and networking services.
• Global Infrastructure: The physical data centres, availability zones, and regions that make up the global AWS network.

Your Responsibility: Security IN the Cloud

Your responsibility is determined by the AWS Cloud services you select. For example, with an Infrastructure as a Service (IaaS) offering like Amazon EC2, you are responsible for managing the guest operating system (including updates and security patches), any application software you install, and configuring the AWS-provided security controls like security groups and network ACLs.

Key areas of your responsibility include:

• Data: You control your data, including where it's stored, how it's encrypted, and who has access to it.
• Identity and Access Management (IAM): You are responsible for managing users, groups, roles, and their permissions. Who can access what?
• Operating System, Network, and Firewall Configuration: You manage the security settings of your instances and virtual networks.
• Encryption: You are responsible for encrypting data both in transit (as it moves to and from AWS) and at rest (while stored on AWS services). AWS Key Management Service (KMS) is a vital tool for this.

This division of labour allows you to focus on your applications and data, while AWS handles the underlying infrastructure, providing a more secure environment than most organisations could build on their own.

Ready to test your knowledge? Let's see what you've learned about the value and responsibilities of using the AWS cloud.

Great work. Now let's review some key terms before moving on.

Understanding the division of responsibility is fundamental to building secure, scalable, and resilient applications on AWS. By leveraging the AWS infrastructure, you can offload the undifferentiated heavy lifting of managing hardware and focus on what truly matters: your applications and your customers.