Multiple provider configurations in Terraform - Step-by-Step Execution

Process Flow - Multiple provider configurations

Define default provider

↓

Define additional provider with alias

↓

Use provider in resource with or without alias

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Terraform applies resources using specified providers

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Resources created in correct cloud accounts/regions

This flow shows how Terraform sets up multiple providers, assigns aliases, and uses them in resources to manage infrastructure across different accounts or regions.

Execution Sample

Terraform

provider "aws" {
  region = "us-east-1"
}

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

resource "aws_s3_bucket" "east_bucket" {
  bucket = "my-east-bucket"
}

resource "aws_s3_bucket" "west_bucket" {
  provider = aws.west
  bucket   = "my-west-bucket"
}

This Terraform code configures two AWS providers for different regions and creates S3 buckets in each region using the appropriate provider.

Process Table

Step	Action	Provider Configured	Resource Created	Region Used
1	Load default provider	aws (default)	None	us-east-1
2	Load aliased provider	aws.west	None	us-west-2
3	Create resource east_bucket	aws (default)	aws_s3_bucket.east_bucket	us-east-1
4	Create resource west_bucket	aws.west	aws_s3_bucket.west_bucket	us-west-2
5	Apply complete	Both providers used	Both buckets created	us-east-1 and us-west-2

💡 All resources created using their specified providers; execution ends.

Status Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	Final
provider.aws.region	undefined	us-east-1	us-east-1	us-east-1	us-east-1	us-east-1
provider.aws.west.region	undefined	undefined	us-west-2	us-west-2	us-west-2	us-west-2
resource.aws_s3_bucket.east_bucket	undefined	undefined	undefined	created	created	created
resource.aws_s3_bucket.west_bucket	undefined	undefined	undefined	undefined	created	created

Key Moments - 3 Insights

Why do we need to use an alias for the second provider?

Because Terraform needs a way to distinguish between multiple configurations of the same provider. The alias lets us tell Terraform which provider to use for each resource, as shown in steps 2 and 4 of the execution_table.

What happens if we don't specify the provider for a resource?

Terraform uses the default provider configuration. In the example, the east_bucket resource uses the default provider (step 3), so it is created in us-east-1.

Can we have more than two provider configurations?

Yes, you can define as many provider configurations with different aliases as needed, each with its own settings. Just assign the correct alias to resources to control where they are created.

Visual Quiz - 3 Questions

Look at the execution_table, which provider is used to create the west_bucket resource?

A aws (default)

B aws.west

C No provider specified

D aws.east

💡 Hint

Check step 4 in the execution_table where the west_bucket resource is created.

At which step does Terraform configure the provider for the us-west-2 region?

A Step 2

B Step 1

C Step 3

D Step 4

💡 Hint

Look at the provider configuration steps in the execution_table.

If we remove the alias from the second provider, what will happen when creating west_bucket?

A Terraform will create west_bucket in us-east-1

B Terraform will create west_bucket in us-west-2

C Terraform will throw an error due to duplicate provider

D Terraform will ignore west_bucket resource

💡 Hint

Consider how Terraform distinguishes multiple provider configs; see key_moments about alias usage.

Concept Snapshot

Terraform Multiple Provider Configurations:
- Define default provider without alias.
- Define additional providers with unique aliases.
- Assign provider to resources using 'provider = provider.alias'.
- Enables managing resources across regions/accounts.
- Avoids conflicts by clear provider references.

Full Transcript

This lesson shows how Terraform handles multiple provider configurations. First, a default provider is defined for one region. Then, an additional provider with an alias is defined for another region. Resources specify which provider to use by referencing the alias or default. Terraform applies resources to the correct regions accordingly. Key points include the need for aliases to distinguish providers and how resources without a provider use the default. This allows managing infrastructure across multiple cloud regions or accounts in one Terraform project.