Overview of Managing Access Permissions to Your Amazon DocumentDB Resources

Every AWS resource is owned by an AWS account, and permissions to create or access the resources are governed by permissions policies. An account administrator can attach permissions policies to IAM identities (that is, users, groups, and roles), and some services (such as AWS Lambda) also support attaching permissions policies to resources.

Note

An account administrator (or administrator user) is a user with administrator permissions. For more information, see IAM Best Practices in the IAM User Guide.

When granting permissions, you decide who is getting the permissions, the resources they get permissions for, and the specific actions that you want to allow on those resources.

Amazon DocumentDB Resources and Operations

In Amazon DocumentDB, the primary resource is a cluster. Amazon DocumentDB supports other resources that can be used with the primary resource such as instances, parameter groups, and event subscriptions. These resources are referred to as subresources.

These resources and subresources have unique Amazon Resource Names (ARNs) associated with them, as shown in the following table.

Amazon DocumentDB provides a set of operations to work with the Amazon DocumentDB resources. For a list of available operations, see Actions.

Understanding Resource Ownership

A resource owner is the AWS account that created a resource. That is, the resource owner is the AWS account of the principal entity (the root account, an IAM user, or an IAM role) that authenticates the request that creates the resource. The following examples illustrate how this works:

• If you use the root account credentials of your AWS account to create an Amazon DocumentDB resource, such as an instance, your AWS account is the owner of the Amazon DocumentDB resource.

• If you create an IAM user in your AWS account and grant permissions to create Amazon DocumentDB resources to that user, the user can create Amazon DocumentDB resources. However, your AWS account, to which the user belongs, owns the Amazon DocumentDB resources.

• If you create an IAM role in your AWS account with permissions to create Amazon DocumentDB resources, anyone who can assume the role can create Amazon DocumentDB resources. Your AWS account, to which the role belongs, owns the Amazon DocumentDB resources.

Managing Access to Resources

A permissions policy describes who has access to what. The following section explains the available options for creating permissions policies.

Note

This section discusses using IAM in the context of Amazon DocumentDB. It doesn’t provide detailed information about the IAM service. For complete IAM documentation, see What Is IAM? in the IAM User Guide. For information about IAM policy syntax and descriptions, see AWS IAM Policy Reference in the IAM User Guide.

Policies that are attached to an IAM identity are referred to as identity-based policies (IAM policies). Policies that are attached to a resource are referred to as resource-based policies. Amazon DocumentDB supports only identity-based policies (IAM policies).

Identity-Based Policies (IAM Policies)

You can attach policies to IAM identities. For example, you can do the following:

• Attach a permissions policy to a user or a group in your account – An account administrator can use a permissions policy that is associated with a particular user to grant permissions for that user to create an Amazon DocumentDB resource, such as an instance.

• Attach a permissions policy to a role (grant cross-account permissions) – You can attach an identity-based permissions policy to an IAM role to grant cross-account permissions. For example, the administrator in Account A can create a role to grant cross-account permissions to another AWS account (for example, Account B) or an AWS service as follows:

  1. Account A administrator creates an IAM role and attaches a permissions policy to the role that grants permissions on resources in Account A.

  2. Account A administrator attaches a trust policy to the role identifying Account B as the principal who can assume the role.

  3. Account B administrator can then delegate permissions to assume the role to any users in Account B. Doing this allows the users in Account B to create or access resources in Account A. The principal in the trust policy can also be an AWS service principal if you want to grant permissions to an AWS service to assume the role.

  For more information about using IAM to delegate permissions, see Access Management in the IAM User Guide.

The following is an example policy that allows the user with the ID 123456789012 to create instances for your AWS account. The new instance must use an option group and a parameter group that starts with default, and it must use the default subnet group.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "AllowCreateDBInstanceOnly",
            "Effect": "Allow",
            "Action": [
                "rds:CreateDBInstance"
            ],
            "Resource": [
                "arn:aws:rds:*:123456789012:db:test*",
                "arn:aws:rds:*:123456789012:pg:cluster-pg:default*",
                "arn:aws:rds:*:123456789012:subgrp:default"
            ]
        }
    ]
}

For more information about using identity-based policies with Amazon DocumentDB, see Using Identity-Based Policies (IAM Policies) for Amazon DocumentDB. For more information about users, groups, roles, and permissions, see Identities (Users, Groups, and Roles) in the IAM User Guide.

Resource-Based Policies

Other services, such as Amazon Simple Storage Service (Amazon S3), also support resource-based permissions policies. For example, you can attach a policy to an S3 bucket to manage access permissions to that bucket. Amazon DocumentDB doesn’t support resource-based policies.

Specifying Policy Elements: Actions, Effects, Resources, and Principals

For each Amazon DocumentDB resource (see Amazon DocumentDB Resources and Operations), the service defines a set of API operations. For more information, see Actions. To grant permissions for these API operations, Amazon DocumentDB defines a set of actions that you can specify in a policy. Performing an API operation can require permissions for more than one action.

The following are the basic policy elements:

• Resource – In a policy, you use an Amazon Resource Name (ARN) to identify the resource to which the policy applies.

• Action – You use action keywords to identify resource operations that you want to allow or deny. For example, the rds:DescribeDBInstances permission allows the user to perform the DescribeDBInstances operation.

• Effect – You specify the effect when the user requests the specific action—this can be either allow or deny. If you don’t explicitly grant access to (allow) a resource, access is implicitly denied. You can also explicitly deny access to a resource, which you might do to make sure that a user cannot access it, even if a different policy grants access.

• Principal – In identity-based policies (IAM policies), the user that the policy is attached to is the implicit principal. For resource-based policies, you specify the user, account, service, or other entity that you want to receive permissions (applies to resource-based policies only). Amazon DocumentDB doesn’t support resource-based policies.

To learn more about IAM policy syntax and descriptions, see AWS IAM Policy Reference in the IAM User Guide.

For a table showing all of the Amazon DocumentDB API actions and the resources that they apply to, see Amazon DocumentDB API Permissions: Actions, Resources, and Conditions Reference.

Specifying Conditions in a Policy

When you grant permissions, you can use the IAM policy language to specify the conditions when a policy should take effect. For example, you might want a policy to be applied only after a specific date. For more information about specifying conditions in a policy language, see Condition in the IAM User Guide.

To express conditions, you use predefined condition keys. Amazon DocumentDB has no service-specific context keys that can be used in an IAM policy. For a list of global condition context keys that are available to all services, see Available Keys for Conditions in the IAM User Guide.