Stateless Web App: WhatIsTheTime.com¶

• WhatIsTheTime.com allows people to know what time it is
• We don't need a [[database]]
• We want to start small and can accept [[downtime]]
• We want to full Vertical scalability and Horizontal scalability, no [[downtime]]
• Let's go through the Solutions Architect journey for this app

Starting simple¶

• Create a single t2.micro instance

Scaling vertically¶

• When we have more traffic for the t2.micro instance to handle, we scale it vertically to something like m5.large.
• [[Downtime]] while upgrading to new instance.

Scaling horizontally¶

• Instead of scaling vertically, we can add multiple instances to balance the load between them.
• In one instance goes away, we can leverage [[Load Balancer]] and Health Checks to route clients to a different instance.
• We can use Auto Scaling Group (ASG) to manage the instance count automatically
• In order to make our app disaster tolerant, we can also make it [[Multi AZ]].