Since AWS is a wide-ranging cloud service provider, it means that it empowers both individuals and organizations of all sizes, at every phase of their business. Small and large enterprise portals to transactional data projects, low traffic websites and personal blogs, to mobile applications and gaming.
This also means that failure can happen any time, and affect the availability of the Amazon cloud and its various services.
Enter AWS Regions.
The Amazon Web Services EC2 service is hosted in different locations worldwide, which are created as Regions. Each AWS Region is intended to be completely isolated from the other AWS Regions by geographical location, and runs independently as well.
This ensures high availability, and stability with fault tolerance.
And it also ensures that end users accessing the cloud do so from their nearest geographic regions for the maximum speed and minimum latency. These are factors that are very important for solutions like apps, games and websites.
Each Region has multiple, isolated locations that Amazon calls Availability Zones, more commonly known as AZ. These are basically made up of one or more datacenters that host AWS services on them. Each Availability Zone is also isolated, but Availability Zones in a Region are connected through low-latency links.
Availability Zones are important from both a design and deployment point of view. That’s because these are essentially datacenters, and prone to failure or downtime. For this reason, it is also a good practice to distribute your resources across multiple Availability Zones so that they remain available even when one of them goes completely offline.
As a global company, AWS has presence across the USA, Europe, Asia, and Australia, with plans underway to launch the first Region in Africa. The company currently has 16 Regions, each containing multiple datacenters within themselves, to make up 42 Availability Zones.
Below is the current list of Regions and their corresponding AWS Region codes, this is how AWS refers to its multiple regions listed below:
These are all the AWS Regions that are available to all AWS accounts. In addition to these, there are also a couple of additional Regions to which Amazon Web Services provides specialized access to.
For any AWS service you choose, you will be prompted to select a corresponding AWS Region in which you want to deploy the service. EC2 gives you the ability to places resources like instances and data in multiple locations with ease. But it is worth keeping in mind that AWS does not replicate resources across Regions automatically — it is up to the end user to set up the replication process for their apps, services, and data.
Generally, you are limited to run a total of 20 on-demand or reserved instances, and can request 100 spot instances per region. However, your instance limit may be lower if you are a new customer. You can find out the most up to date details regarding limits here.
There are no data transfer charges between two Amazon services within the same region. However, you will be billed separately for data transferred between multiple regions, as well as usage of other AWS services. Have a look at the regional pricing per region for EC2 here