Managed policies and inline policies - Amazon Identity and Access Management
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Managed policies and inline policies

When you need to set the permissions for an identity in IAM, you must decide whether to use an Amazon managed policy, a customer managed policy, or an inline policy. The following sections provide more information about each of the types of identity-based policies and when to use them.

Amazon managed policies

An Amazon managed policy is a standalone policy that is created and administered by Amazon. Standalone policy means that the policy has its own Amazon Resource Name (ARN) that includes the policy name. For example, arn:aws:iam::aws:policy/IAMReadOnlyAccess is an Amazon managed policy. For more information about ARNs, see IAM ARNs.

Amazon managed policies are designed to provide permissions for many common use cases. Full access Amazon managed policies such as AmazonDynamoDBFullAccess and IAMFullAccess define permissions for service administrators by granting full access to a service. Power-user Amazon managed policies such as AWSCodeCommitPowerUser and AWSKeyManagementServicePowerUser are designed for power users. Partial-access Amazon managed policies such as AmazonMobileAnalyticsWriteOnlyAccess and AmazonEC2ReadOnlyAccess provide specific levels of access to Amazon services without allowing permissions management access level permissions. Amazon managed policies make it easier for you to assign appropriate permissions to users, groups, and roles than if you had to write the policies yourself.

One particularly useful category of Amazon managed policies are those designed for job functions. These policies align closely to commonly used job functions in the IT industry. The intent is to make granting permissions for these common job functions easy. One key advantage of using job function policies is that they are maintained and updated by Amazon as new services and API operations are introduced. For example, the AdministratorAccess job function provides full access and permissions delegation to every service and resource in Amazon. We recommend that this policy is used only for the account administrator. For power users that require full access to every service except limited access to IAM and Organizations, use the PowerUserAccess job function. For a list and descriptions of the job function policies, see Amazon managed policies for job functions.

You cannot change the permissions defined in Amazon managed policies. Amazon occasionally updates the permissions defined in an Amazon managed policy. When Amazon does this, the update affects all principal entities (users, groups, and roles) that the policy is attached to. Amazon is most likely to update an Amazon managed policy when a new Amazon service is launched or new API calls become available for existing services. For example, the Amazon managed policy called ReadOnlyAccess provides read-only access to all Amazon services and resources. When Amazon launches a new service, Amazon updates the ReadOnlyAccess policy to add read-only permissions for the new service. The updated permissions are applied to all principal entities that the policy is attached to.

The following diagram illustrates Amazon managed policies. The diagram shows three Amazon managed policies: AdministratorAccess, PowerUserAccess, and AmazonCloudTrailReadOnlyAccess. Notice that a single Amazon managed policy can be attached to principal entities in different Amazon accounts, and to different principal entities in a single Amazon account.


        Diagram of Amazon managed policies

Customer managed policies

You can create standalone policies that you administer in your own Amazon account, which we refer to as customer managed policies. You can then attach the policies to multiple principal entities in your Amazon account. When you attach a policy to a principal entity, you give the entity the permissions that are defined in the policy.

A great way to create a customer managed policy is to start by copying an existing Amazon managed policy. That way you know that the policy is correct at the beginning and all you need to do is customize it to your environment.

The following diagram illustrates customer managed policies. Each policy is an entity in IAM with its own Amazon Resource Name (ARN) that includes the policy name. Notice that the same policy can be attached to multiple principal entities—for example, the same DynamoDB-books-app policy is attached to two different IAM roles.


        Diagram of customer managed policies

Inline policies

An inline policy is a policy that's embedded in an IAM identity (a user, group, or role). That is, the policy is an inherent part of the identity. You can create a policy and embed it in an identity, either when you create the identity or later.

The following diagram illustrates inline policies. Each policy is an inherent part of the user, group, or role. Notice that two roles include the same policy (the DynamoDB-books-app policy), but they are not sharing a single policy; each role has its own copy of the policy.


        Diagram of inline policies

Choosing between managed policies and inline policies

The different types of policies are for different use cases. In most cases, we recommend that you use managed policies instead of inline policies.

Managed policies provide the following features:

Reusability

A single managed policy can be attached to multiple principal entities (users, groups, and roles). In effect, you can create a library of policies that define permissions that are useful for your Amazon account, and then attach these policies to principal entities as needed.

Central change management

When you change a managed policy, the change is applied to all principal entities that the policy is attached to. For example, if you want to add permission for a new Amazon API, you can update the managed policy to add the permission. (If you're using an Amazon managed policy, Amazon updates to the policy.) When the policy is updated, the changes are applied to all principal entities that the policy is attached to. In contrast, to change an inline policy you must individually edit each identity that contains the policy. For example, if a group and a role both contain the same inline policy, you must individually edit both principal entities in order to change that policy.

Versioning and rolling back

When you change a customer managed policy, the changed policy doesn't overwrite the existing policy. Instead, IAM creates a new version of the managed policy. IAM stores up to five versions of your customer managed policies. You can use policy versions to revert a policy to an earlier version if you need to.

A policy version is different from a Version policy element. The Version policy element is used within a policy and defines the version of the policy language. To learn more about policy versions, see Versioning IAM policies. To learn more about the Version policy element see IAM JSON policy elements: Version.

Delegating permissions management

You can allow users in your Amazon account to attach and detach policies while maintaining control over the permissions defined in those policies. In effect, you can designate some users as full administrators—that is, administrators that can create, update, and delete policies. You can then designate other users as limited administrators. That is, administrators that can attach policies to other principal entities, but only the policies that you have allowed them to attach.

For more information about delegating permissions management, see Controlling access to policies.

Automatic updates for Amazon managed policies

Amazon maintains Amazon managed policies and updates them when necessary (for example, to add permissions for new Amazon services), without you having to make changes. The updates are automatically applied to the principal entities that you have attached the Amazon managed policy to.

Using inline policies

Inline policies are useful if you want to maintain a strict one-to-one relationship between a policy and the identity that it's applied to. For example, you want to be sure that the permissions in a policy are not inadvertently assigned to an identity other than the one they're intended for. When you use an inline policy, the permissions in the policy cannot be inadvertently attached to the wrong identity. In addition, when you use the Amazon Web Services Management Console to delete that identity, the policies embedded in the identity are deleted as well. That's because they are part of the principal entity.