Virtual Private Clouds (VPCs) are the backbone of any organization’s AWS Cloud solution. They mimic a traditional network setup – but without the considerable downsides of a self-managed on-premise data center and while still allowing room for scaling your infrastructure at need. It’s a great way of saving money, staying up to date, and ensuring infrastructure security, which is why moving critical applications and data to the cloud has become a necessity for all modern organizations.
However, there is a drawback: Subnets (that is, the set of addresses that belong to a given group of resources inside a VPC) can only exist inside one Availability Zone and therefore, Region at a time…and AZs inside those regions can sometimes fail, turning an AWS Availability Zone into an UN-availability zone.
Happily, AWS recommends a solution that ensures organizations’ clients, customers, and staff retain access to their vital resources even if the worst happens: architecting for high availability by utilizing multiple AZs in their VPC design.