terraform-aws-secrets-manager

Terraform module to create Amazon Secrets Manager resources with comprehensive input validation and advanced features.

AWS Secrets Manager helps you protect secrets needed to access your applications, services, and IT resources. The service enables you to easily rotate, manage, and retrieve database credentials, API keys, and other secrets throughout their lifecycle.

Features

✅ Input Validation: Comprehensive validation for all variables to prevent configuration errors
✅ Type Safety: Strongly typed variables with structured object definitions
✅ Secret Rotation: Built-in support for automatic secret rotation with Lambda functions
✅ Cross-Region Replication: Support for replicating secrets across AWS regions
✅ KMS Encryption: Support for customer-managed KMS keys
✅ Resource Policies: Attach custom IAM policies to secrets
✅ Flexible Secret Types: Support for plain text, key/value pairs, and binary secrets

Examples

Check the examples folder where you can see the complete compilation of snippets.

Basic Usage

Plain text secrets

module "secrets-manager-1" {
  source = "lgallard/secrets-manager/aws"

  secrets = {
    secret-1 = {
      description             = "My secret 1"
      recovery_window_in_days = 7
      secret_string           = "This is an example"
    },
    secret-2 = {
      description             = "My secret 2"
      recovery_window_in_days = 7
      secret_string           = "This is another example"
    }
  }

  tags = {
    Owner       = "DevOps team"
    Environment = "dev"
    Terraform   = true
  }
}

Key/Value secrets

module "secrets-manager-2" {
  source = "lgallard/secrets-manager/aws"

  secrets = {
    secret-kv-1 = {
      description = "This is a key/value secret"
      secret_key_value = {
        key1 = "value1"
        key2 = "value2"
      }
      recovery_window_in_days = 7
    },
    secret-kv-2 = {
      description = "Another key/value secret"
      secret_key_value = {
        username = "user"
        password = "topsecret"
      }
      tags = {
        app = "web"
      }
      recovery_window_in_days = 7
    },
  }

  tags = {
    Owner       = "DevOps team"
    Environment = "dev"
    Terraform   = true
  }
}

Binary secrets

module "secrets-manager-3" {
  source = "lgallard/secrets-manager/aws"

  secrets = {
    secret-binary-1 = {
      description   = "This is a binary secret"
      secret_binary = "ssh-rsa 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 lgallard@server1"
      recovery_window_in_days = 7
    },
    secret-binary-2 = {
      name                    = "secret-binary-2"
      description             = "Another binary secret"
      secret_binary           = "ssh-rsa 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 lgallard@server2"
      recovery_window_in_days = 7
      tags = {
        app = "web"
      }
    }
  }

  tags = {
    Owner       = "DevOps team"
    Environment = "dev"
    Terraform   = true
  }
}

Advanced Usage

Secrets with KMS Encryption

module "secrets-manager-kms" {
  source = "lgallard/secrets-manager/aws"

  secrets = {
    database-credentials = {
      description = "Database credentials encrypted with customer KMS key"
      secret_key_value = {
        username = "admin"
        password = "super-secret-password"
        host     = "db.example.com"
        port     = "5432"
      }
      kms_key_id              = "arn:aws:kms:us-east-1:123456789012:key/12345678-1234-1234-1234-123456789012"
      recovery_window_in_days = 7
    }
  }

  tags = {
    Environment = "production"
    KMSEncrypted = "true"
  }
}

Secrets with Resource Policies

data "aws_iam_policy_document" "secret_policy" {
  statement {
    sid    = "AllowApplicationAccess"
    effect = "Allow"
    
    principals {
      type        = "AWS"
      identifiers = ["arn:aws:iam::123456789012:role/MyApplicationRole"]
    }
    
    actions   = ["secretsmanager:GetSecretValue"]
    resources = ["*"]
  }
}

module "secrets-manager-policy" {
  source = "lgallard/secrets-manager/aws"

  secrets = {
    app-config = {
      description   = "Application configuration with resource policy"
      secret_string = jsonencode({
        api_key = "secret-api-key"
        config  = "production-config"
      })
      policy                  = data.aws_iam_policy_document.secret_policy.json
      recovery_window_in_days = 14
    }
  }
}

Cross-Region Secret Replication

module "secrets-manager-replication" {
  source = "lgallard/secrets-manager/aws"

  secrets = {
    global-config = {
      description   = "Global configuration replicated across regions"
      secret_string = "global-configuration-data"
      
      replica_regions = {
        "us-west-2" = "arn:aws:kms:us-west-2:123456789012:key/12345678-1234-1234-1234-123456789012"
        "eu-west-1" = "arn:aws:kms:eu-west-1:123456789012:key/87654321-4321-4321-4321-210987654321"
      }
      
      force_overwrite_replica_secret = true
      recovery_window_in_days        = 7
    }
  }

  tags = {
    ReplicationEnabled = "true"
    GlobalResource     = "true"
  }
}

Secrets Rotation

If you need to rotate your secrets, use rotate_secrets map to define them. The lambda function must exist and have the right permissions to rotate secrets in AWS Secrets Manager:

module "secrets-manager-rotation" {
  source = "lgallard/secrets-manager/aws"

  rotate_secrets = {
    database-password = {
      description             = "Database password rotated every 30 days"
      secret_string           = "initial-password"
      rotation_lambda_arn     = "arn:aws:lambda:us-east-1:123456789012:function:rotate-secret"
      automatically_after_days = 30
      recovery_window_in_days = 15
    },
    api-key = {
      description             = "API key rotated weekly"
      secret_string           = "initial-api-key"
      rotation_lambda_arn     = "arn:aws:lambda:us-east-1:123456789012:function:rotate-secret"
      automatically_after_days = 7
      recovery_window_in_days = 7
    }
  }

  tags = {
    Owner       = "DevOps team"
    Environment = "dev"
    Terraform   = true
  }
}

# Lambda function for rotation (example)
# AWS templates available at https://github.com/aws-samples/aws-secrets-manager-rotation-lambdas
module "rotate_secret_lambda" {
  source  = "spring-media/lambda/aws"
  version = "5.2.0"

  filename         = "secrets_manager_rotation.zip"
  function_name    = "rotate-secret"
  handler          = "secrets_manager_rotation.lambda_handler"
  runtime          = "python3.9"
  source_code_hash = filebase64sha256("${path.module}/secrets_manager_rotation.zip")

  environment = {
    variables = {
      SECRETS_MANAGER_ENDPOINT = "https://secretsmanager.us-east-1.amazonaws.com"
    }
  }
}

resource "aws_lambda_permission" "allow_secret_manager_call_lambda" {
  function_name = module.rotate_secret_lambda.function_name
  statement_id  = "AllowExecutionSecretManager"
  action        = "lambda:InvokeFunction"
  principal     = "secretsmanager.amazonaws.com"
}

Mixed Secret Definitions

You can define different types of secrets (string, key/value, or binary) in the same secrets or rotate_secrets map:

module "secrets-manager-mixed" {
  source = "lgallard/secrets-manager/aws"

  secrets = {
    plain-text-secret = {
      description             = "A plain text secret"
      recovery_window_in_days = 7
      secret_string           = "This is a plain text secret"
    }
    
    key-value-secret = {
      description = "A key/value secret for database credentials"
      secret_key_value = {
        username = "dbuser"
        password = "dbpassword"
        host     = "database.example.com"
        port     = "5432"
        database = "myapp"
      }
      recovery_window_in_days = 14
      tags = {
        Type = "database"
      }
    }
    
    binary-secret = {
      description   = "SSH private key"
      secret_binary = "-----BEGIN PRIVATE KEY-----\nMIIEvgIBADANBgkqhkiG9w0BAQEFAASCBKgwggSkAgEAAoIBAQC..."
      recovery_window_in_days = 30
      tags = {
        Type = "ssh-key"
      }
    }
  }

  tags = {
    Owner       = "DevOps team"
    Environment = "dev"
    Terraform   = true
  }
}

Input Validation Reference

This module includes comprehensive input validation to prevent configuration errors:

Secret Names

Must contain only alphanumeric characters, hyphens, underscores, periods, forward slashes, at signs, plus signs, and equal signs
Must be between 1 and 512 characters long
Examples: my-secret, app/config, db_credentials

Recovery Window

Must be 0 (immediate deletion) or between 7-30 days
Default: 30 days

Rotation Frequency

Must be between 1-365 days for automatically_after_days
Default: 30 days

Version Stages

Only AWSCURRENT and AWSPENDING are valid
Example: ["AWSCURRENT"]

KMS Key IDs

Must be valid KMS key ARN, alias, or key ID format
Examples:
- ARN: arn:aws:kms:us-east-1:123456789012:key/12345678-1234-1234-1234-123456789012
- Alias: alias/my-key
- Key ID: 12345678-1234-1234-1234-123456789012

Troubleshooting

Common Issues and Solutions

Invalid Secret Name Error

Error: Secret names must contain only alphanumeric characters, hyphens, underscores, periods, forward slashes, at signs, plus signs, and equal signs.

Solution: Check your secret names for invalid characters. Only use: a-z, A-Z, 0-9, -, _, ., /, @, +, =

Recovery Window Validation Error

Error: Recovery window must be 0 (for immediate deletion) or between 7 and 30 days.

Solution: Set recovery_window_in_days to either 0 or a value between 7 and 30.

KMS Key Format Error

Error: KMS key ID must be a valid KMS key ARN, alias, or key ID format.

Solution: Ensure your KMS key follows one of these formats:

arn:aws:kms:region:account:key/key-id
alias/key-alias
key-id (UUID format)

Rotation Lambda Missing Error

Error: All rotate_secrets must have a valid rotation_lambda_arn specified.

Solution: When using rotate_secrets, always provide a valid rotation_lambda_arn. The Lambda function must exist and have proper permissions.

Tag Validation Error

Error: Tag keys cannot start with 'aws:' (case insensitive).

Solution: Remove any tags that start with aws:, AWS:, or any case variation.

Performance Considerations

Large Numbers of Secrets: If you have many secrets, consider splitting them across multiple module instances to improve Terraform performance.
Cross-Region Replication: Be aware that replication increases costs and may impact performance. Only replicate secrets that truly need global availability.
Rotation Frequency: More frequent rotations increase Lambda costs and API calls. Balance security requirements with operational costs.

Security Best Practices

Least Privilege Access: Use resource policies to grant minimal required permissions.
Encryption: Always use KMS encryption for sensitive secrets, preferably with customer-managed keys.
Monitoring: Enable CloudTrail logging for Secrets Manager API calls to monitor access patterns.
Rotation: Implement regular rotation for database credentials and API keys.
Version Management: Use version stages appropriately and avoid storing multiple active versions unnecessarily.

Version 0.5.0+ breaking changes

Issue #13 highlighted the fact that changing the secrets order will recreate the secrets (for example, adding a new secret in the top of the list o removing a secret that is not the last one). The suggested approach to tackle this issue was to use for_each to iterate over a map of secrets.

Version 0.5.0 has this implementation, but it's not backward compatible. Therefore you must migrate your Terraform code and the objects in the tfstate.

Migrating the code:

Before 0.5.0 your secrets were defined as list as follow:

  secrets = [
    {
      name                    = "secret-1"
      description             = "My secret 1"
      recovery_window_in_days = 7
      secret_string           = "This is an example"
    },
  ]

After version 0.5.0 you have to define you secrets as a map:

  secrets = {
    secret-1 = {
      description             = "My secret 1"
      recovery_window_in_days = 7
      secret_string           = "This is an example"
    },
  }

Notice that the map key is the name of the secret, thefore a name field is not needed anymore.

Migrating the objects in the tfstate file

To avoid recreating your already deploy secrets you can rename or move the object in the tfstate file as follow:

terraform state mv 'module.secrets-manager-1.aws_secretsmanager_secret_version.sm-sv['0']' 'module.secrets-manager-1.aws_secretsmanager_secret_version.sm-sv["secret-1"]'

Another option is to use a script to iterate over your secrets. In the migration-scripts folder you'll find a couple of scripts that can be used as a starting point.

For example, to migrate a module named secrets-manager-1 run the script as follow:

$ ./secret_list_to_map.sh secrets-manager-1

Move "module.secrets-manager-1.aws_secretsmanager_secret.sm[0]" to "module.secrets-manager-1.aws_secretsmanager_secret.sm[\"secret-1\"]"
Successfully moved 1 object(s).
Move "module.secrets-manager-1.aws_secretsmanager_secret_version.sm-sv[0]" to "module.secrets-manager-1.aws_secretsmanager_secret_version.sm-sv[\"secret-1\"]"
Successfully moved 1 object(s).
Move "module.secrets-manager-1.aws_secretsmanager_secret.sm[1]" to "module.secrets-manager-1.aws_secretsmanager_secret.sm[\"secret-2\"]"
Successfully moved 1 object(s).
Move "module.secrets-manager-1.aws_secretsmanager_secret_version.sm-sv[1]" to "module.secrets-manager-1.aws_secretsmanager_secret_version.sm-sv[\"secret-2\"]"
Successfully moved 1 object(s).

Requirements

Name	Version
aws	>= 2.67.0

Providers

Name	Version
aws	5.23.1

Modules

No modules.

Resources

Name	Type
aws_secretsmanager_secret.rsm	resource
aws_secretsmanager_secret.sm	resource
aws_secretsmanager_secret_rotation.rsm-sr	resource
aws_secretsmanager_secret_version.rsm-sv	resource
aws_secretsmanager_secret_version.rsm-svu	resource
aws_secretsmanager_secret_version.sm-sv	resource
aws_secretsmanager_secret_version.sm-svu	resource

Inputs

Name	Description	Type	Default	Required
automatically_after_days	Specifies the number of days between automatic scheduled rotations of the secret. Must be between 1 and 365 days. Example: 30	`number`	`30`	no
recovery_window_in_days	Specifies the number of days that AWS Secrets Manager waits before it can delete the secret. This value can be 0 to force deletion without recovery or range from 7 to 30 days. Example: 7	`number`	`30`	no
rotate_secrets	Map of secrets to keep and rotate in AWS Secrets Manager. Each secret must include rotation_lambda_arn.	map(object({ description = optional(string) name = optional(string) name_prefix = optional(string) secret_string = optional(string) secret_key_value = optional(map(string)) secret_binary = optional(string) kms_key_id = optional(string) policy = optional(string) force_overwrite_replica_secret = optional(bool, false) recovery_window_in_days = optional(number) rotation_lambda_arn = string automatically_after_days = optional(number) replica_regions = optional(map(string), {}) tags = optional(map(string), {}) }))	`{}`	no
secrets	Map of secrets to keep in AWS Secrets Manager. Example: { mysecret = { description = "My secret", secret_string = "secret-value" } }	map(object({ description = optional(string) name = optional(string) name_prefix = optional(string) secret_string = optional(string) secret_key_value = optional(map(string)) secret_binary = optional(string) kms_key_id = optional(string) policy = optional(string) force_overwrite_replica_secret = optional(bool, false) recovery_window_in_days = optional(number) replica_regions = optional(map(string), {}) tags = optional(map(string), {}) }))	`{}`	no
tags	Key-value map of user-defined tags attached to the secret. Keys cannot start with 'aws:'. Example: { Environment = "prod", Owner = "team" }	`map(string)`	`{}`	no
unmanaged	Terraform must ignore secrets lifecycle. Using this option you can initialize the secrets and rotate them outside Terraform, avoiding other users changing or rotating secrets by subsequent Terraform runs. Example: true	`bool`	`false`	no
version_stages	List of version stages to be handled. Valid values are 'AWSCURRENT' and 'AWSPENDING'. Kept as null for backwards compatibility. Example: ["AWSCURRENT"]	`list(string)`	`null`	no

Outputs

Name	Description
rotate_secret_arns	Map of rotating secret names to their ARNs. Use these ARNs to grant permissions or reference rotating secrets in IAM policies and other AWS resources.
rotate_secret_ids	Map of rotating secret names to their resource IDs. Use these IDs to reference rotating secrets in other Terraform resources.
secret_arns	Map of secret names to their ARNs. Use these ARNs to grant permissions or reference secrets in IAM policies and other AWS resources.
secret_ids	Map of secret names to their resource IDs. Use these IDs to reference secrets in other Terraform resources.

Variable Reference

secrets / rotate_secrets Object Structure

Each secret in the secrets or rotate_secrets map supports the following attributes:

Required for rotate_secrets

rotation_lambda_arn (string) - ARN of the Lambda function for secret rotation

Optional Attributes

description (string) - Human-readable description of the secret
name (string) - Custom name for the secret (if not provided, uses map key)
name_prefix (string) - Prefix for auto-generated secret names
secret_string (string) - Plain text secret value
secret_key_value (map(string)) - Key-value pairs for structured secrets
secret_binary (string) - Binary secret data (will be base64 encoded)
kms_key_id (string) - KMS key for encryption (ARN, alias, or key ID)
policy (string) - JSON resource policy for the secret
force_overwrite_replica_secret (bool) - Force overwrite replica secrets (default: false)
recovery_window_in_days (number) - Recovery window (0, or 7-30 days)
automatically_after_days (number) - Days between automatic rotations (1-365, for rotate_secrets only)
replica_regions (map(string)) - Map of regions to KMS key IDs for replication
tags (map(string)) - Additional tags for the secret (merged with module-level tags)

Example Variable Usage

secrets = {
  # Plain text secret
  "app-config" = {
    description   = "Application configuration"
    secret_string = "my-config-value"
    tags = {
      Application = "myapp"
    }
  }
  
  # Key-value secret with KMS encryption
  "database-creds" = {
    description = "Database credentials"
    secret_key_value = {
      username = "admin"
      password = "secret123"
      host     = "db.example.com"
    }
    kms_key_id              = "alias/my-secrets-key"
    recovery_window_in_days = 7
  }
  
  # Binary secret
  "ssh-key" = {
    description   = "SSH private key"
    secret_binary = file("${path.module}/private_key.pem")
    tags = {
      Type = "ssh-key"
    }
  }
}

rotate_secrets = {
  # Rotating database password
  "db-password" = {
    description             = "Auto-rotating database password"
    secret_string           = "initial-password"
    rotation_lambda_arn     = "arn:aws:lambda:us-east-1:123456789012:function:rotate-secret"
    automatically_after_days = 30
    recovery_window_in_days = 14
  }
}

Name		Name	Last commit message	Last commit date
Latest commit History 134 Commits
.github		.github
examples		examples
.pre-commit-config.yaml		.pre-commit-config.yaml
.release-please-config.json		.release-please-config.json
.release-please-manifest.json		.release-please-manifest.json
CHANGELOG.md		CHANGELOG.md
LICENSE		LICENSE
README.md		README.md
main.tf		main.tf
outputs.tf		outputs.tf
renovate.json		renovate.json
variables.tf		variables.tf
versions.tf		versions.tf

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terraform-aws-secrets-manager

Features

Examples

Basic Usage

Plain text secrets

Key/Value secrets

Binary secrets

Advanced Usage

Secrets with KMS Encryption

Secrets with Resource Policies

Cross-Region Secret Replication

Secrets Rotation

Mixed Secret Definitions

Input Validation Reference

Secret Names

Recovery Window

Rotation Frequency

Version Stages

KMS Key IDs

Tags

Troubleshooting

Common Issues and Solutions

Invalid Secret Name Error

Recovery Window Validation Error

KMS Key Format Error

Rotation Lambda Missing Error

Tag Validation Error

Performance Considerations

Security Best Practices

Version 0.5.0+ breaking changes

Migrating the code:

Migrating the objects in the tfstate file

Requirements

Providers

Modules

Resources

Inputs

Outputs

Variable Reference

secrets / rotate_secrets Object Structure

Required for rotate_secrets

Optional Attributes

Example Variable Usage

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