Why is CloudFormation important?

By now, the benefits of automation should be starting to become apparent to you. But don't fall in to the trap of thinking CloudFormation will be useful only for large collections of resources. Even performing the simplest task of, say, creating an S3 bucket can get very repetitive if you need to do it in every region.

We work with a lot of customers who have very tight controls and governance around their infrastructure, and especially in the network layer (think VPCs, NACLs, and security groups). Being able to express one's cloud footprint in YAML (or JSON), store it in a source code repository, and funnel it through a high-visibility pipeline gives these customers confidence that their infrastructure changes are peer-reviewed and will work as expected in production. Discipline and commitment to IaC SDLC practices are of course a big factor in this, but CloudFormation helps bring us out of the era of following 20-page run-sheets for manual changes, navigating untracked or unexplained configuration drift, and unexpected downtime caused by fat fingers.