Terraform

• Tools for building, changing, and versioning infrastructure efficiently in a declarative way
• Automates the creation, modification, and deletion of infrastructure components, making the process more efficient and consistent.
• Enables application software best practices to infrastructure

Terraform Files and Structure

• Main Configuration (.tf files)
  • .tf files contain Terraform configuration code (e.g., main.tf, variables.tf, outputs.tf).
  • .tf.json files are JSON-based configurations (less common).
• State File (terraform.tfstate)
  • JSON file containing information and the current state of managed infrastructure.
  • Contain sensitive information info (database password).
  • Can be stored locally or remotely for collaboration (backend "gcs", backend "s3").
• Lock File (.terraform.lock.hcl)
  • Ensures provider versions remain consistent across different environments.
• Variable Files (.tfvars)
  • Used for defining reusable variables outside of .tf files.
  • Example: terraform.tfvars containing project-specific values.

Terraform Core

Terraform Core acts as the execution engine responsible for:

• Parsing .tf files
• Communicating with providers
• Managing Terraform State

Terraform Sequence

1. Initialize (terraform init) – Sets up and download providers & backends.
2. Plan (terraform plan) – Shows changes that will be applied before execution.
3. Apply (terraform apply) – Creates/upgrades resources.
4. Destroy (terraform destroy) – Removes infrastructure that specified in config file.