With a partial configuration, the remaining configuration arguments must be provided as part of the initialization process.

1. Create file with name s3backend.tfvars.

A backend configuration file has the contents of the backend block as top-level attributes, without the need to wrap it in another terraform or backend block:

bucket          = "backet-name"
key             = "file-name"
region          = "eu-central-1"
encrypt         = "true"

2. Then apply configuration:

$ terraform init -backend-config=s3backend.tfvars

module "aws-ssm-parameter" {
  source = "path-to-module"

  name       = "example"
  prefix     = "/dev"
  bucket     = "backet-name"
  key        = "file-name"
  region     = "eu-central-1"
  encrypt    = "true"

  tags = {
    ManagedBy = "Terraform"
    Team      = "DevOps"
  }

  parameters = {
    "foo_os_endpoint" = {
      description = "Endpoint URL for foo opensearch"
      type        = "SecureString"
      value       = "https://localhost:9200"
    },

    "foo_os_user" = {
      description = "Engine for foo opensearch"
      type        = "SecureString"
    },

    "foo_os_password" = {
      description = "Password for foo opensearch"
      type        = "SecureString"
    },
  }
}

terraform {
  backend "s3" {}
}

The following arguments are supported:

• name - (Required) The name of the service to which this parameter list belongs, e.g., example. The value is appended to the prefix.

• parameter - (Required) A parameter block. Parameter blocks are documented below.

• prefix - (Optional) Prefix prepended to parameter name, and used to produce a hierarchical layout of parameters. Default: /service.

• tags - (Optional) A map of tags to be applied to resources where supported.

A parameter block consists of a map of maps. Each map's key represents a parameter name. The value stored under this key consists of another map that may contain the following keys:

• description – (Optional) A description of the parameter. If not specified, a default value is assigned that draws attention to the need to provide a meaningful description.

• type – (Optional) The parameter's type. The values String and SecureString are permissible, with SecureString being the default.

• prefix – (Optional) A string prepended to the parameter name to allow hierarchical organization of SSM parameters. The default prefix is /service, which is sufficient for most use.

• value – (Optional) The initial value for the parameter. Note that the value is used only on creation of the parameter. The parameter value is never overwritten by Terraform.