---
description: >-
  The providers meta-argument specifies which provider configurations from a
  parent module are available in a child module.
---

# The Module `providers` Meta-Argument

In a [module call](../../language/modules/syntax.mdx) block, the
optional `providers` meta-argument specifies which
[provider configurations](../../language/providers/configuration.mdx) from the parent
module will be available inside the child module.

```hcl
# The default "aws" configuration is used for AWS resources in the root
# module where no explicit provider instance is selected.
provider "aws" {
  region = "us-west-1"
}

# An alternate configuration is also defined for a different
# region, using the alias "usw2".
provider "aws" {
  alias  = "usw2"
  region = "us-west-2"
}

# An example child module is instantiated with the alternate configuration,
# so any AWS resources it defines will use the us-west-2 region.
module "example" {
  source    = "./example"
  providers = {
    aws = aws.usw2
  }
}
```

## Default Behavior: Inherit Default Providers

If the child module does not declare any [configuration aliases](../../language/modules/develop/providers.mdx#provider-aliases-within-modules),
the `providers` argument is optional. If you omit it, a child module inherits
all of the _default_ provider configurations from its parent module. (Default
provider configurations are ones that don't use the `alias` argument.)

If you specify a `providers` argument, it cancels this default behavior, and the
child module will _only_ have access to the provider configurations you specify.

## Usage and Behavior

The value of `providers` is a map, where:

- The keys are the provider configuration names used inside the child module.
- The values are provider configuration names from the parent module.

Both keys and values should be unquoted references to provider configurations.
For default configurations, this is the local name of the provider; for
alternate configurations, this is a `<PROVIDER>.<ALIAS>` reference.

Within a child module, resources are assigned to provider configurations as
normal — either OpenTofu chooses a default based on the name of the resource
type, or the resource specifies an alternate configuration with the `provider`
argument. If the module receives a `providers` map when it's called, the
provider configuration names used within the module are effectively remapped to
refer the specified configurations from the parent module.

## When to Specify Providers

There are two main reasons to use the `providers` argument:

- Using different default provider configurations for a child module.
- Configuring a module that requires multiple configurations of the same provider.

### Changing Default Provider Configurations

Most re-usable modules only use default provider configurations, which they can
automatically inherit from their caller when `providers` is omitted.

However, in OpenTofu configurations that use multiple configurations of the
same provider, you might want some child modules to use the default provider
configuration and other ones to use an alternate. (This usually happens when
using one configuration to manage resources in multiple different regions of the
same cloud provider.)

By using the `providers` argument (like in the code example above), you can
accommodate this without needing to edit the child module. Although the code
within the child module always refers to the default provider configuration, the
actual configuration of that default can be different for each instance.

### Modules With Alternate Provider Configurations

In rare cases, a single re-usable module might require multiple configurations
of the same provider. For example, a module that configures connectivity between
networks in two AWS regions is likely to need both a source and a destination
region. In that case, the root module may look something like this:

```hcl
provider "aws" {
  alias  = "usw1"
  region = "us-west-1"
}

provider "aws" {
  alias  = "usw2"
  region = "us-west-2"
}

module "tunnel" {
  source    = "./tunnel"
  providers = {
    aws.src = aws.usw1
    aws.dst = aws.usw2
  }
}
```

Non-default provider configurations are never automatically inherited, so any
module that works like this will always need a `providers` argument. The
documentation for the module should specify all of the provider configuration
names it needs.

## More Information for Module Developers

For more details and guidance about working with providers inside a re-usable
child module, see
[Module Development: Providers Within Modules](../../language/modules/develop/providers.mdx).
