AWS IAM Terraform module

Terraform module which creates AWS IAM resources.

Usage

Please refer to the AWS published IAM Best Practices for up to date guidance on IAM best practices.

IAM Account

Creates an account policy and account alias. Module instantiation is once per account.

module "iam_account" {
  source  = "terraform-aws-modules/iam/aws//modules/iam-account"

  account_alias = "awesome-company"

  max_password_age               = 90
  minimum_password_length        = 24
  require_uppercase_characters   = true
  require_lowercase_characters   = true
  require_numbers                = true
  require_symbols                = true
  password_reuse_prevention      = 3
  allow_users_to_change_password = true
}

IAM Group

Creates an IAM group with IAM policy attached that one or more users can be added to.

module "iam_group" {
  source  = "terraform-aws-modules/iam/aws//modules/iam-group"

  name = "superadmins"

  users = [
    "user1",
    "user2"
  ]

  enable_self_management_permissions = true
  permissions = {
    AssumeRole = {
      actions   = ["sts:AssumeRole"]
      resources = ["arn:aws:iam::111111111111:role/admin"]
    }
  }

  policies = {
    AdministratorAccess = "arn:aws:iam::aws:policy/AdministratorAccess",
  }

  tags = {
    Terraform   = "true"
    Environment = "dev"
  }
}

IAM OIDC Provider

Creates an OpenID connect provider. Useful for trusting external identity providers such as GitHub, Bitbucket, etc.

[!TIP] An IAM provider is 1 per account per given URL. This module would be provisioned once per AWS account, and then one or more roles can be created with this provider as the trusted identity.

module "iam_oidc_provider" {
  source    = "terraform-aws-modules/iam/aws//modules/iam-oidc-provider"

  url = "https://token.actions.githubusercontent.com"

  tags = {
    Terraform   = "true"
    Environment = "dev"
  }
}

IAM Policy

Creates an IAM policy.

module "iam_policy" {
  source  = "terraform-aws-modules/iam/aws//modules/iam-policy"

  name        = "example"
  path        = "/"
  description = "My example policy"

  policy = <<-EOF
    {
      "Version": "2012-10-17",
      "Statement": [
        {
          "Action": [
            "ec2:Describe*"
          ],
          "Effect": "Allow",
          "Resource": "*"
        }
      ]
    }
  EOF

  tags = {
    Terraform   = "true"
    Environment = "dev"
  }
}

IAM ReadOnly Policy

Creates an IAM policy that allows read-only access to the list of AWS services provided.

module "iam_read_only_policy" {
  source  = "terraform-aws-modules/iam/aws//modules/iam-read-only-policy"

  name        = "example"
  path        = "/"
  description = "My example read-only policy"

  allowed_services = ["rds", "dynamo", "health"]

  tags = {
    Terraform   = "true"
    Environment = "dev"
  }
}

IAM Role

Creates an IAM role with a trust policy and (optional) IAM instance profile. Useful for service roles such as EC2, ECS, etc., or roles assumed across AWS accounts.

module "iam_role" {
  source  = "terraform-aws-modules/iam/aws//modules/iam-role"

  name = "example"

  trust_policy_permissions = {
    TrustRoleAndServiceToAssume = {
      actions = [
        "sts:AssumeRole",
        "sts:TagSession",
      ]
      principals = [{
        type = "AWS"
        identifiers = [
          "arn:aws:iam::835367859851:user/anton",
        ]
      }]
      condition = [{
        test     = "StringEquals"
        variable = "sts:ExternalId"
        values   = ["some-secret-id"]
      }]
    }
  }

  policies = {
    AmazonCognitoReadOnly      = "arn:aws:iam::aws:policy/AmazonCognitoReadOnly"
    AlexaForBusinessFullAccess = "arn:aws:iam::aws:policy/AlexaForBusinessFullAccess"
    custom                     = aws_iam_policy.this.arn
  }

  tags = {
    Terraform   = "true"
    Environment = "dev"
  }
}

IAM Role - GitHub OIDC

Creates an IAM role that trusts an OpenID connect provider. Useful for trusting external identity providers such as GitHub, Bitbucket, etc.

module "iam_role_github_oidc" {
  source    = "terraform-aws-modules/iam/aws//modules/iam-role"

  enable_github_oidc = true

  # This should be updated to suit your organization, repository, references/branches, etc.
  oidc_wildcard_subjects = ["terraform-aws-modules/terraform-aws-iam:*"]

  policies = {
    S3ReadOnly = "arn:aws:iam::aws:policy/AmazonS3ReadOnlyAccess"
  }

  tags = {
    Terraform   = "true"
    Environment = "dev"
  }
}

IAM Role - SAML 2.0

Creates an IAM role that trusts a SAML provider. Useful for trusting external identity providers such as Okta, OneLogin, etc.

module "iam_role_saml" {
  source  = "terraform-aws-modules/iam/aws//modules/iam-role"

  name = "example"

  enable_saml       = true
  saml_provider_ids = ["arn:aws:iam::235367859851:saml-provider/idp_saml"]

  policies = {
    ReadOnlyAccess = "arn:aws:iam::aws:policy/ReadOnlyAccess"
  }

  tags = {
    Terraform   = "true"
    Environment = "dev"
  }
}

IAM Role for EKS Service Accounts (IRSA)

[!TIP] Upgrade to use EKS Pod Identity instead of IRSA A similar module for EKS Pod Identity is available here.

Creates an IAM role that is suitable for EKS IAM role for service accounts (IRSA) with a set of pre-defined policies for common EKS addons.

module "vpc_cni_irsa" {
  source = "terraform-aws-modules/iam/aws//modules/iam-role-for-service-accounts"

  name   = "vpc-cni"

  attach_vpc_cni_policy = true
  vpc_cni_enable_ipv4   = true

  oidc_providers = {
    this = {
      provider_arn               = "arn:aws:iam::012345678901:oidc-provider/oidc.eks.us-east-1.amazonaws.com/id/5C54DDF35ER19312844C7333374CC09D"
      namespace_service_accounts = ["kube-system:aws-node"]
    }
  }

  tags = {
    Terraform   = "true"
    Environment = "dev"
  }
}

IAM User

Creates an IAM user with ability to create a login profile, access key, and SSH key.

module "iam_user" {
  source  = "terraform-aws-modules/iam/aws//modules/iam-user"

  name = "vasya.pupkin"

  force_destroy           = true
  pgp_key                 = "keybase:test"
  password_reset_required = false

  tags = {
    Terraform   = "true"
    Environment = "dev"
  }
}

Known limitations (Terraform/OpenTofu, not this module)

A few requests come up again and again and cannot be implemented by this module, or by any module: Terraform requires lifecycle arguments to be literal values inside the resource block. hashicorp/terraform#18367 has been open since 2018, #22544 since 2019, and opentofu/opentofu#1329 is the same request for OpenTofu.

• Terraform keeps reverting tags on IAM roles - Native options: move tag ownership into Terraform with provider default_tags, or fork this module and add ignore_changes = [tags, tags_all].

Compliance.tf serves this module with these rules applied at download time, on top of whatever your organization already has enabled there. Inputs and outputs do not change; the source line does. Drop the version argument and pin the release you use by adding &version= and that release number to the URL. To get started, register a free compliance.tf account and configure an access token:

source = "https://registry.compliance.tf/terraform-aws-modules/iam/aws//modules/iam-role?add_rules=lifecycle_ignore_tags"

The full workaround for each item above, and the exact diff each rule makes, are in the compliance.tf docs for this module. To preview a diff without an account, open this module in the Rules Playground.

Disclosure: written by this module's maintainer, who also builds compliance.tf.

Examples

• iam-account - Set AWS account alias and password policy
• iam-group - IAM group with users who are allowed to assume IAM roles in another AWS account and have access to specified IAM policies
• iam-oidc-provider - Create an OpenID connect provider and IAM role which can be assumed from specified subjects federated from the OIDC provider
• iam-policy - Create an IAM policy
• iam-read-only-policy - Create IAM read-only policy
• iam-role - Create individual IAM role which can be assumed from specified ARNs (AWS accounts, IAM users, etc)
• iam-role-for-service-accounts - Create IAM role for service accounts (IRSA) for use within EKS clusters
• iam-user - Add IAM user, login profile and access keys (with PGP enabled or disabled)

Authors

Module is maintained by Anton Babenko with help from these awesome contributors.

License

Apache-2.0 Licensed. See LICENSE.

Additional information for users from Russia and Belarus

• Russia has illegally annexed Crimea in 2014 and brought the war in Donbas followed by full-scale invasion of Ukraine in 2022.
• Russia has brought sorrow and devastations to millions of Ukrainians, killed hundreds of innocent people, damaged thousands of buildings, and forced several million people to flee.
• Putin khuylo!