Amazon Resource Names (ARNs) - AWS General Reference
ARN formatPaths in ARNs

Amazon Resource Names (ARNs)

Amazon Resource Names (ARNs) uniquely identify AWS resources. We require an ARN when you need to specify a resource unambiguously across all of AWS, such as in IAM policies, Amazon Relational Database Service (Amazon RDS) tags, and API calls.

The Service Authorization Reference lists the ARNs that you can use in IAM policies.

ARN format

The following are the general formats for ARNs. The specific formats depend on the resource. To use an ARN, replace the italicized text with the resource-specific information. Be aware that the ARNs for some resources omit the Region, the account ID, or both the Region and the account ID. 

arn:partition:service:region:account-id:resource-id
arn:partition:service:region:account-id:resource-type/resource-id
arn:partition:service:region:account-id:resource-type:resource-id
partition

The partition in which the resource is located. A partition is a group of AWS Regions. Each AWS account is scoped to one partition.

The following are the supported partitions:

  • aws -AWS Regions

  • aws-cn - China Regions

  • aws-us-gov - AWS GovCloud (US) Regions

service

The service namespace that identifies the AWS product. For example, s3 for Amazon S3. To find a service namespace, open the Service Authorization Reference, open the page for the service, and find the phrase "service prefix" in the first sentence. For example, the following text appears in the first sentence on the page for Amazon S3: 

(service prefix: s3)
region

The Region code. For example, us-east-2 for US East (Ohio). For the list of Region codes, see Regional endpoints.

account-id

The ID of the AWS account that owns the resource, without the hyphens. For example, 123456789012.

resource-id

The resource identifier. This part of the ARN can be the name or ID of the resource or a resource path. For example, user/Bob for an IAM user or instance/i-1234567890abcdef0 for an EC2 instance. Some resource identifiers include a parent resource (sub-resource-type/parent-resource/sub-resource) or a qualifier such as a version (resource-type:resource-name:qualifier).

Paths in ARNs

Resource ARNs can include a path. For example, in Amazon S3, the resource identifier is an object name that can include slashes (/) to form a path. Similarly, IAM user names and group names can include paths.

Paths can include a wildcard character, namely an asterisk (*). For example, if you are writing an IAM policy, you can specify all IAM users that have the path product_1234 using a wildcard as follows: 

arn:aws:iam::123456789012:user/Development/product_1234/*

Similarly, you can specify user/* to mean all users or group/* to mean all groups, as in the following examples: 

"Resource":"arn:aws:iam::123456789012:user/*"
"Resource":"arn:aws:iam::123456789012:group/*"

The following example shows ARNs for an Amazon S3 bucket in which the resource name includes a path: 

arn:aws:s3:::my_corporate_bucket/*
arn:aws:s3:::my_corporate_bucket/Development/*

Incorrect wildcard usage

You cannot use a wildcard in the portion of the ARN that specifies the resource type, such as the term user in an IAM ARN. For example, the following is not allowed. 

arn:aws:iam::123456789012:u*   <== not allowed