Terraform Providers and Resources

Terraform uses providers to interact with APIs and resources to model infrastructure objects.

Providers

A provider is a plugin that manages resources for a specific platform, such as AWS, Azure, or local files.

Example provider block:

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.0"
    }
  }
}
 
provider "aws" {
  region = "us-east-1"
}

Resources

Resources declare the infrastructure objects you want to create.

Example S3 bucket resource:

resource "aws_s3_bucket" "website" {
  bucket = "shellrag-terraform-demo"
  acl    = "private"
}

Terraform computes dependencies automatically. If a resource references another resource, Terraform builds them in the right order.

Variables and outputs

Use variables to parameterize your configuration:

variable "region" {
  type    = string
  default = "us-east-1"
}
 
provider "aws" {
  region = var.region
}

Create outputs to share values after apply:

output "bucket_name" {
  value = aws_s3_bucket.website.id
}

Plan before you apply

Run terraform plan to inspect changes before applying them:

terraform plan

This helps prevent accidental resource changes and keeps infrastructure updates safe.