Amazon ECS
User Guide for AWS Fargate (API Version 2014-11-13)

How Amazon Elastic Container Service Works with IAM

Before you use IAM to manage access to Amazon ECS, you should understand what IAM features are available to use with Amazon ECS. To get a high-level view of how Amazon ECS and other AWS services work with IAM, see AWS Services That Work with IAM in the IAM User Guide.

Amazon ECS Identity-Based Policies

With IAM identity-based policies, you can specify allowed or denied actions and resources as well as the conditions under which actions are allowed or denied. Amazon ECS supports specific actions, resources, and condition keys. To learn about all of the elements that you use in a JSON policy, see IAM JSON Policy Elements Reference in the IAM User Guide.

Actions

The Action element of an IAM identity-based policy describes the specific action or actions that will be allowed or denied by the policy. Policy actions usually have the same name as the associated AWS API operation. The action is used in a policy to grant permissions to perform the associated operation.

Policy actions in Amazon ECS use the following prefix before the action: ecs:. For example, to grant someone permission to create an Amazon ECS cluster with the Amazon ECS CreateCluster API operation, you include the ecs:CreateCluster action in their policy. Policy statements must include either an Action or NotAction element. Amazon ECS defines its own set of actions that describe tasks that you can perform with this service.

To specify multiple actions in a single statement, separate them with commas as follows:

"Action": [ "ecs:action1", "ecs:action2"

You can specify multiple actions using wildcards (*). For example, to specify all actions that begin with the word Describe, include the following action:

"Action": "ecs:Describe*"

To see a list of Amazon ECS actions, see Supported Resource-Level Permissions for Amazon ECS API Actions.

Resources

The Resource element specifies the object or objects to which the action applies. Statements must include either a Resource or a NotResource element. You specify a resource using an ARN or using the wildcard (*) to indicate that the statement applies to all resources.

The Amazon ECS cluster resource has the following ARN:

arn:${Partition}:ecs:${Region}:${Account}:cluster/${clusterName}

For more information about the format of ARNs, see Amazon Resource Names (ARNs) and AWS Service Namespaces.

For example, to specify the my-cluster cluster in your statement, use the following ARN:

"Resource": "arn:aws:ecs:us-east-1:123456789012:cluster/my-cluster"

To specify all clusters that belong to a specific account, use the wildcard (*):

"Resource": "arn:aws:ecs:us-east-1:123456789012:cluster/*"

Some Amazon ECS actions, such as those for creating resources, cannot be performed on a specific resource. In those cases, you must use the wildcard (*).

"Resource": "*"

Some Amazon ECS API actions can be performed on multiple resources. For example, multiple clusters can be referenced when calling the DescribeClusters API action. To specify multiple resources in a single statement, separate the ARNs with commas.

"Resource": [ "resource1", "resource2"

The following table describes the ARNs for each resource type used by the Amazon ECS API actions.

Important

The following table uses the new longer ARN format for Amazon ECS tasks, services, and container instances. If you have not opted in to the long ARN format, the ARNs will not include the cluster name. For more information, see Amazon Resource Names (ARNs) and IDs.

Resource Type

ARN

All Amazon ECS resources

arn:aws:ecs:*

All Amazon ECS resources owned by the specified account in the specified region

arn:aws:ecs:region:account:*

Cluster

arn:aws:ecs:region:account:cluster/cluster-name

Container instance

arn:aws:ecs:region:account:container-instance/cluster-name/container-instance-id

Task definition

arn:aws:ecs:region:account:task-definition/task-definition-family-name:task-definition-revision-number

Service

arn:aws:ecs:region:account:service/cluster-name/service-name

Task

arn:aws:ecs:region:account:task/cluster-name/task-id

Container

arn:aws:ecs:region:account:container/container-id

To learn with which actions you can specify the ARN of each resource, see Supported Resource-Level Permissions for Amazon ECS API Actions.

Condition Keys

The Condition element (or Condition block) lets you specify conditions in which a statement is in effect. The Condition element is optional. You can build conditional expressions that use condition operators, such as equals or less than, to match the condition in the policy with values in the request.

If you specify multiple Condition elements in a statement, or multiple keys in a single Condition element, AWS evaluates them using a logical AND operation. If you specify multiple values for a single condition key, AWS evaluates the condition using a logical OR operation. All of the conditions must be met before the statement's permissions are granted.

You can also use placeholder variables when you specify conditions. For example, you can grant an IAM user permission to access a resource only if it is tagged with their IAM user name. For more information, see IAM Policy Elements: Variables and Tags in the IAM User Guide.

Amazon ECS defines its own set of condition keys and also supports using some global condition keys. To see all AWS global condition keys, see AWS Global Condition Context Keys in the IAM User Guide.

Amazon ECS implements the following service-specific condition keys.

Condition Key

Description

Evaluation Types

aws:RequestTag/${TagKey}

The context key is formatted "aws:RequestTag/tag-key":"tag-value" where tag-keyand tag-value are a tag key and value pair.

Checks that the tag key–value pair is present in an AWS request. For example, you could check to see that the request includes the tag key "Dept" and that it has the value "Accounting".

String

aws:ResourceTag/${TagKey}

The context key is formatted "aws:ResourceTag/tag-key":"tag-value" where tag-keyand tag-value are a tag key and value pair.

Checks that the tag attached to the identity resource (user or role) matches the specified key name and value.

String

aws:TagKeys

This context key is formatted "aws:TagKeys":"tag-key" where tag-key is a list of tag keys without values (for example, ["Dept","Cost-Center"]).

Checks the tag keys that are present in an AWS request.

String

ecs:ResourceTag/${TagKey}

The context key is formatted "ecs:ResourceTag/tag-key":"tag-value" where tag-keyand tag-value are a tag key and value pair.

Checks that the tag attached to the identity resource (user or role) matches the specified key name and value.

String

ecs:cluster

The context key is formatted "ecs:cluster":"cluster-arn" where cluster-arn is the ARN for the Amazon ECS cluster.

ARN, Null

ecs:container-instances

The context key is formatted "ecs:container-instances":"container-instance-arns" where container-instance-arns is one or more container instance ARNs.

ARN, Null

ecs:task-definition

The context key is formatted "ecs:task-definition":"task-definition-arn" where task-definition-arn is the ARN for the Amazon ECS task definition.

ARN, Null

ecs:service

The context key is formatted "ecs:service":"service-arn" where service-arn is the ARN for the Amazon ECS service.

ARN, Null

To learn with which actions and resources you can use a condition key, see Supported Resource-Level Permissions for Amazon ECS API Actions.

Examples

To view examples of Amazon ECS identity-based policies, see Amazon Elastic Container Service Identity-Based Policy Examples.

Amazon ECS Resource-Based Policies

Amazon ECS does not support resource-based policies.

Authorization Based on Amazon ECS Tags

You can attach tags to Amazon ECS resources or pass tags in a request to Amazon ECS. To control access based on tags, you provide tag information in the condition element of a policy using the aws:RequestTag/key-name or aws:TagKeys condition keys. For more information, see Controlling Access Using Tags in the IAM User Guide.

For more information about tagging Amazon ECS resources, see Resources and Tags.

To view an example identity-based policy for limiting access to a resource based on the tags on that resource, see Describing Amazon ECS Services Based on Tags.

Amazon ECS IAM Roles

An IAM role is an entity within your AWS account that has specific permissions.

Using Temporary Credentials with Amazon ECS

You can use temporary credentials to sign in with federation, assume an IAM role, or to assume a cross-account role. You obtain temporary security credentials by calling AWS STS API operations such as AssumeRole or GetFederationToken.

Amazon ECS supports using temporary credentials.

Service-Linked Roles

Service-linked roles allow AWS services to access resources in other services to complete an action on your behalf. Service-linked roles appear in your IAM account and are owned by the service. An IAM administrator can view but not edit the permissions for service-linked roles.

Amazon ECS supports service-linked roles. For details about creating or managing Amazon ECS service-linked roles, see Service-Linked Roles for Amazon ECS.

Service Roles

This feature allows a service to assume a service role on your behalf. This role allows the service to access resources in other services to complete an action on your behalf. Service roles appear in your IAM account and are owned by the account. This means that an IAM administrator can change the permissions for this role. However, doing so might break the functionality of the service.

Amazon ECS supports service roles.