What are some alternatives?
When comparing AWS CloudFormation and Semaphore, you can also consider the following products
Codeship - Codeship is a fast and secure hosted Continuous Delivery platform that scales with your needs.
Jenkins - Jenkins is an open-source continuous integration server with 300+ plugins to support all kinds of software development
Bamboo - Bamboo is a continuous integration and deployment tool that ties automated builds, tests and releases together in a single workflow.
CircleCI - CircleCI gives web developers powerful Continuous Integration and Deployment with easy setup and maintenance.
Octopus Deploy - Octopus is a friendly deployment automation tool for .NET developers.
Travis CI - Focus on writing code. Let Travis CI take care of running your tests and deploying your apps.