Providers and Resources (the building blocks of Terraform)

Terraform is built from:

• Providers: integrations with cloud APIs
• Resources: real infrastructure objects you manage

Learning outcomes

You’ll learn:

• how to configure a provider
• how resources are declared
• how Terraform references resource attributes

1) Providers

A provider block configures connection settings for a platform.

Example (AWS):

provider "aws" {
  region = var.aws_region
}

Provider configuration can include credentials, endpoints, and more.

2) Resources

A resource declares infrastructure you want Terraform to manage.

Generic shape:

resource "<provider_resource_type>" "<name>" {
  # arguments...
}

AWS S3 bucket example

resource "aws_s3_bucket" "example" {
  bucket = "my-unique-bucket-name-12345" # must be globally unique
}

Terraform identifies resources as:

• resource type: aws_s3_bucket
• name: example

So the full reference is:

• aws_s3_bucket.example

3) Arguments vs attributes

• Arguments are what you set:
  • bucket = "..."
• Attributes are what Terraform gets (often after apply):
  • aws_s3_bucket.example.bucket

Example output:

output "bucket_name" {
  value = aws_s3_bucket.example.bucket
}

4) Referencing resources (dependency wiring)

When you reference an attribute, Terraform can infer dependencies.

Example: create an S3 bucket and use its name elsewhere.

resource "aws_s3_bucket" "uploads" {
  bucket = "my-unique-uploads-bucket-12345"
}

resource "aws_s3_bucket_versioning" "uploads_versioning" {
  bucket = aws_s3_bucket.uploads.id

  versioning_configuration {
    status = "Enabled"
  }
}

Because bucket = aws_s3_bucket.uploads.id, Terraform knows it must create the bucket first.

5) Required provider + version constraints

Use terraform { required_providers ... } to lock down versions.

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.0"
    }
  }
}

6) Resource meta-arguments (useful building blocks)

Terraform supports meta-arguments such as:

• count
• for_each
• depends_on

We’ll cover these patterns in the next tutorials.

7) Small complete example

main.tf

terraform {
  required_version = ">= 1.6.0"
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.0"
    }
  }
}

provider "aws" {
  region = var.aws_region
}

resource "aws_s3_bucket" "example" {
  bucket = "my-unique-bucket-name-12345"
}

output "bucket_name" {
  value = aws_s3_bucket.example.bucket
}

variables.tf

variable "aws_region" {
  type    = string
  default = "us-east-1"
}

Run:

terraform init
terraform validate
terraform plan
terraform apply

Replace the bucket name with a globally unique name.