The ever-increasing demands on IT infrastructures and the rise of continuous integration and continuous deployment (CI/CD) pipelines have pushed the need for consistent and scalable automation. This is where infrastructure as code (IaC) comes into play. IaC is the provisioning, configuring, and management of infrastructure through formatted, machine-readable files. Instead of manually setting up on-premises and cloud environments administrators and architects can just automate them with IaC. IaC works well with infrastructure as a service (IaaS) and has been adopted by organizations to develop and deploy scalable cloud implementations faster and at reduced costs.
While the IaC concept bears similarities to programming scripts (which also automate IT processes), IaC uses descriptive language for coding more adaptive provisioning and deployments (that is, the software itself is responsible for initiating infrastructure changes). IaC is considered especially crucial for cloud computing and DevOps.
Source: Trend Micro