Evolving architecture against increasing loads
Auto scaling is not the single thing that fixes everything. In real life, you will probably evolve your architecture against an increasing number of users or load. In this section, we will suggest actions you can take at each stage of your growth starting from a handful of users right up to tens of millions of users for a typical web stack.
Scaling from one to half a million users
In the beginning, you can get started with a single EC2 instance that hosts your web service and the DB on the same instance. You can provision an EIP and use Route53 for DNS services. This should be sufficient to handle a typical website or service for a new business.
As your number of users increases to several hundreds or thousands, there are several easy-to-upgrade options available to scale your infrastructure. The simplest first step is to get a bigger EC2 instance (scale vertically). You can also leverage instance types (high I/O, memory, compute, storage intensive...
