Chef, Puppet, and Ansible are all configuration management tools, which means they are designed to install and manage software on existing servers. CloudFormation, Heat, Pulumi, and Terraform are provisioning tools, which means they are designed to provision the servers themselves (as well as the rest of your infrastructure, like load balancers, databases, networking configuration, etc), leaving the job of configuring those servers to other tools. Although the distinction is not entirely clear cut, given that configuration management tools can typically do some degree of provisioning (e.g., you can deploy a server with Ansible) and that provisioning tools can typically do some degree of configuration (e.g., you can run configuration scripts on each server you provision with Terraform), you typically want to pick the tool that’s the best fit for your use case.

In particular, we’ve found that if you use Docker or Packer, the vast majority of your configuration management needs are already taken care of. With Docker and Packer, you can create images (such as containers or virtual machine images) that have all the software your server needs already installed and configured. Once you have such an image, all you need is a server to run it. And if all you need to do is provision a bunch of servers, then a provisioning tool like Terraform is typically going to be a better fit than a configuration management tool (here’s an example of how to use Terraform to deploy Docker on AWS).

That said, if you’re not using server templating tools, a good alternative is to use a configuration management and provisioning tool together. For example, a popular combination is to use Terraform to provision your servers and Ansible to configure each one.