Support for the Region Argument in all resources

[carlcauchi]

Is your request related to a new offering from AWS? ✅

Yes — AWS now supports passing a region argument directly to MemoryDB resources in the AWS Terraform Provider (v6.0+), enabling cross-region configuration without relying solely on provider alias blocks.

Describe the solution you'd like

Add support for the region argument in the MemoryDB module so users can explicitly set the AWS region for MemoryDB clusters, subnet groups, and associated resources.

This aligns with the new AWS provider functionality that allows RDS/MemoryDB-style resources to specify region directly.

https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/memorydb_cluster#region-2

This will:

• Improve multi-region deployment workflows-
• Reduce dependency on aliased provider configuration-
• Ensure consistency with updated AWS provider capabilities

Describe alternatives you've considered

Using provider alias blocks for each region — functional but adds complexity when operating in multiple regions.

Additional context

Adding region support will allow the module to be used more easily in multi-region architectures and follow the new AWS provider support for regional overrides at the resource level.

Thanks in advance for considering! 🙏

[bryantbiggs]

I'm curious, what is the motivation behind wanting to setup cross region replication with the region argument?

[carlcauchi]

I'm curious, what is the motivation behind wanting to setup cross region replication with the region argument?

Thanks for the question!
To clarify — this request isn’t for cross-region replication.

The motivation is to avoid having to declare and pass multiple aliased providers when deploying the module across multiple regions. With the AWS provider v6+ support for the region argument, we can simply iterate over regions (e.g., for_each on a region map) and let the resource handle its own region setting.

This enables cleaner, more scalable multi-region patterns without maintaining separate provider blocks such as:

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

provider "aws" {
  alias  = "eu-central-1"
  region = "eu-central-1"
}

Instead, we could do:

for_each = var.regions

region = each.value

This keeps code DRY, improves maintainability, and aligns the module with the new Terraform AWS provider capabilities.

[bryantbiggs]

added in #16