Providers

Providers are used to interact with the APIs of various platforms. They are used to create, update and delete resources.

Some include:

• Cloud providers (AWS, Azure, GCP)
• Databases (MySQL, PostgreSQL)
• SaaS Platforms (GitHub, Datadog, PagerDuty)

They are separate plugins and are downloaded when running terraform init

TO get an overview of the providers used by a module, run terraform providers

Tier

They are divided into three tiers:

• Official: maintained by HashiCorp
• Verified: maintained by a partner of HashiCorp
• Community: maintained by the community (no guarantee of maintenance)

Registry

The Terraform Registry is a public index of providers and modules. It is used to discover providers and modules and download them.

Configuration Block

• The configuration block is used to configure the provider. It is defined at the root of the configuration.
• Its different for each provider

Aliases

• Aliases are used to configure multiple instances of the same provider (for example, multiple AWS accounts, or different regions)
• They are created by adding an alias argument to the provider block:

provider "aws" {
  alias = "west"
  region = "us-west-2"
}

• They can be used in the resource level, module level or parent provider level:

resource "aws_instance" "example" {
  provider = aws.west
  # ...
}

module "vpc" {
  source = "./vpc"
  providers = {
    aws = aws.west
  }
}

terraform {
    required_providers {
        aws = {
        source = "hashicorp/aws"
        version = "~> 3.0"
        configuration_aliases = [ aws.west ]
        }
    }
}

This last declaration specifies that when another module calls this one it must explicitly provide a provider configuration named aws.west, rather than just inheriting a default AWS provider configuration automatically.