terraform

Terraform is an open-source infrastructure as code tool created by HashiCorp. It enables users to provision, change, and version infrastructure across multiple cloud providers and on-premises systems by describing desired resources in declarative configuration files. The primary configuration language is HashiCorp Configuration Language (HCL), though JSON can also be used.

Terraform configurations define providers, resources, data sources, variables, and outputs. Providers are plugins that integrate with service APIs (such as cloud platforms, virtualization platforms, or SaaS services). Terraform builds a dependency graph from the configuration to determine the correct order of operations for creating, updating, or destroying resources. It maintains a state file that maps real-world resources to their configuration, enabling drift detection and incremental changes. State can be stored locally or remotely using backends, which may offer encryption and locking for safe collaboration.

The typical workflow includes initializing the working directory with terraform init, previewing changes with terraform plan, and applying changes with terraform apply. Users can import existing resources into state and organize configurations into reusable modules. Remote backends and services like Terraform Cloud support team collaboration, policy enforcement, and centralized state management.

Providers and ecosystems: Terraform supports a wide range of providers for public clouds (AWS, Azure, Google Cloud), Kubernetes, virtualization platforms, and numerous SaaS offerings. The platform's registry hosts many community and vendor-backed providers, enabling multi-cloud and hybrid deployments.

Use cases include reproducible environments, multi-cloud provisioning, and automated infrastructure pipelines. Considerations include managing sensitive data in state, choosing appropriate backends, and handling potential drift between configuration and live resources.