What is Amazon Web Services (AWS)?

Amazon Web Services (AWS) is the cloud computing business of Amazon. It rents out computing power, storage and other IT services over the internet, so a business can run servers and software without buying or housing the equipment. AWS has offered these services since 2006.

You sign in to a web console, choose what you need, and it is ready within minutes. When you no longer need it, you turn it off.

The main kinds of service

AWS lists more than 200 services. Most businesses only ever meet a few kinds.

• Compute is virtual servers that run your software. The AWS product is called Amazon EC2.
• Storage is space for files, backups and archives. The best known product is Amazon S3.
• Databases are run by AWS, which looks after the equipment and the software underneath while you look after the data.
• Networking and security covers private networks, firewall rules and the system that decides who may sign in and what they may touch.

Where the data lives in Australia

AWS groups its data centres into Regions. Each Region contains several Availability Zones, and a zone is one or more separate data centres with their own power and network connections.

There are two Regions in Australia: Asia Pacific (Sydney) and Asia Pacific (Melbourne). Each has three Availability Zones. Sydney is switched on for every account. Melbourne is a newer Region, and it has to be enabled in the account before anything can be created there.

You choose the Region each time you create something. AWS suggests picking one that has the services you need and is close to most of the people who will use it.

How it is charged

AWS describes most of its pricing as pay as you go: you are billed for what you use, without a long contract. Servers are charged by the hour or the second from the moment they start until they are stopped. Storage is usually charged by the gigabyte, and so is data sent out of AWS to the internet.

A business with steady needs can commit to a set amount of use for one or three years and pay a lower rate. Because the bill follows usage, a test server that nobody turned off is still being paid for. Ask whoever manages the account to set a budget and review the bill each month.

Who is responsible for what

AWS calls this the shared responsibility model. AWS looks after “security of the cloud”: the buildings, hardware, software and networks that run its services. The customer looks after “security in the cloud”, and how much that covers depends on the service.

• On a virtual server, you look after the operating system, including its updates and security patches, and the firewall rules around it.
• On a storage service such as S3, AWS runs the platform. You manage the data, the encryption options and the permissions.

The Australian Signals Directorate makes the same point about every cloud provider: the risk to your data stays with you and cannot be handed to the provider. Before anything goes onto AWS, find out who will patch the servers, who controls the sign-ins and where the backups are kept.