Terraform is an open source project maintained by HashiCorp, which gives an infrastructure as code (IaC) interface to cloud providers.
The idea behind IaC is that instead of managing cloud infrastructure via the console UI or explicitly calling create/delete/update APIs. The code describes the desired state of affairs.
The system (in this case, Terraform) is responsible for reconciling the actual cloud infrastructure with the desired state. This means that the infrastructure is managed as code; updates to the infrastructure are code reviewed, ...
