How Amazon Elastic Container Service works with IAM

Before you use IAM to manage access to Amazon ECS, learn what IAM features are available to use with Amazon ECS.

IAM feature	Amazon ECS support
Identity-based policies	Yes
Resource-based policies	No
Policy actions	Yes
Policy resources	Partial
Policy condition keys	Yes
ACLs	No
ABAC (tags in policies)	Yes
Temporary credentials	Yes
Forward access sessions (FAS)	Yes
Service roles	Yes
Service-linked roles	Yes

To get a high-level view of how Amazon ECS and other AWS services work with most IAM features, see AWS services that work with IAM in the IAM User Guide.

Identity-based policies for Amazon ECS

Supports identity-based policies: Yes

Identity-based policies are JSON permissions policy documents that you can attach to an identity, such as an IAM user, group of users, or role. These policies control what actions users and roles can perform, on which resources, and under what conditions. To learn how to create an identity-based policy, see Creating IAM policies in the IAM User Guide.

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. You can't specify the principal in an identity-based policy because it applies to the user or role to which it is attached. To learn about all of the elements that you can use in a JSON policy, see IAM JSON policy elements reference in the IAM User Guide.

Identity-based policy examples for Amazon ECS

To view examples of Amazon ECS identity-based policies, see Identity-based policy examples for Amazon Elastic Container Service.

Resource-based policies within Amazon ECS

Supports resource-based policies: No

Resource-based policies are JSON policy documents that you attach to a resource. Examples of resource-based policies are IAM role trust policies and Amazon S3 bucket policies. In services that support resource-based policies, service administrators can use them to control access to a specific resource. For the resource where the policy is attached, the policy defines what actions a specified principal can perform on that resource and under what conditions. You must specify a principal in a resource-based policy. Principals can include accounts, users, roles, federated users, or AWS services.

To enable cross-account access, you can specify an entire account or IAM entities in another account as the principal in a resource-based policy. Adding a cross-account principal to a resource-based policy is only half of establishing the trust relationship. When the principal and the resource are in different AWS accounts, an IAM administrator in the trusted account must also grant the principal entity (user or role) permission to access the resource. They grant permission by attaching an identity-based policy to the entity. However, if a resource-based policy grants access to a principal in the same account, no additional identity-based policy is required. For more information, see Cross account resource access in IAM in the IAM User Guide.

Policy actions for Amazon ECS

Supports policy actions: Yes

Administrators can use AWS JSON policies to specify who has access to what. That is, which principal can perform actions on what resources, and under what conditions.

The Action element of a JSON policy describes the actions that you can use to allow or deny access in a policy. Policy actions usually have the same name as the associated AWS API operation. There are some exceptions, such as permission-only actions that don't have a matching API operation. There are also some operations that require multiple actions in a policy. These additional actions are called dependent actions.

Include actions in a policy to grant permissions to perform the associated operation.

To see a list of Amazon ECS actions, see Actions defined by Amazon Elastic Container Service in the Service Authorization Reference.

Policy actions in Amazon ECS use the following prefix before the action:

ecs

To specify multiple actions in a single statement, separate them with commas.

"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 view examples of Amazon ECS identity-based policies, see Identity-based policy examples for Amazon Elastic Container Service.

Policy resources for Amazon ECS

Supports policy resources: Partial

Administrators can use AWS JSON policies to specify who has access to what. That is, which principal can perform actions on what resources, and under what conditions.

The Resource JSON policy element specifies the object or objects to which the action applies. Statements must include either a Resource or a NotResource element. As a best practice, specify a resource using its Amazon Resource Name (ARN). You can do this for actions that support a specific resource type, known as resource-level permissions.

For actions that don't support resource-level permissions, such as listing operations, use a wildcard (*) to indicate that the statement applies to all resources.

"Resource": "*"

To see a list of Amazon ECS resource types and their ARNs, see Resources defined by Amazon Elastic Container Service in the Service Authorization Reference. To learn with which actions you can specify the ARN of each resource, see Actions defined by Amazon Elastic Container Service.

Some Amazon ECS API actions support 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": [
      "EXAMPLE-RESOURCE-1",
      "EXAMPLE-RESOURCE-2"

For example, the Amazon ECS cluster resource has the following ARN:

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

To specify my-cluster-1 and my-cluster-2 cluster in your statement, use the following ARNs:

"Resource": [
         "arn:aws:ecs:us-east-1:123456789012:cluster/my-cluster-1",
         "arn:aws:ecs:us-east-1:123456789012:cluster/my-cluster-2"
      

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

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

For task definitions, you can specify the latest revision, or a specific revision.

To specify all revisions of the task definition, use the wildcard (*):

"Resource:arn:${Partition}:ecs:${Region}:${Account}:task-definition/${TaskDefinitionFamilyName}:*"

To specify a specific task definition revision, use ${TaskDefinitionRevisionNumber}:

"Resource:arn:${Partition}:ecs:${Region}:${Account}:task-definition/${TaskDefinitionFamilyName}:${TaskDefinitionRevisionNumber}"

To view examples of Amazon ECS identity-based policies, see Identity-based policy examples for Amazon Elastic Container Service.

Policy condition keys for Amazon ECS

Supports service-specific policy condition keys: Yes

Administrators can use AWS JSON policies to specify who has access to what. That is, which principal can perform actions on what resources, and under what conditions.

The Condition element (or Condition block) lets you specify conditions in which a statement is in effect. The Condition element is optional. You can create 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.

AWS supports global condition keys and service-specific condition keys. To see all AWS global condition keys, see AWS global condition context keys in the IAM User Guide.

Amazon ECS supports the following service-specific condition keys that you can use to provide fine-grained filtering for your IAM policies:

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:container-name	The context key is formatted "ecs:container-name":"container-name" where container-instance- is the name of an Amazon ECS container which is defined in the task definition.	String
ecs:enable-execute-command	The context key is formatted "ecs:enable-execute-command":"value" where value- is "true" or "false".	String
ecs:enable-service-connect	The context key is formatted "ecs:enable-service-connect":"value" where value is "true" or "false".	String
ecs:enable-ebs-volumes	The context key is formatted "ecs:enable-ebs-volumes":"value" where value is "true" or "false".	String
ecs:namespace	The context key is formatted "ecs:namespace":"namespace-arn" where namespace-arn is the ARN for the AWS Cloud Map namespace.	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
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:account-setting	The context key is formatted "ecs:account-setting":"account-setting" where account-setting is the name of an Amazon ECS account setting.	String

To see a list of Amazon ECS condition keys, see Condition keys for Amazon Elastic Container Service in the Service Authorization Reference. To learn with which actions and resources you can use a condition key, see Actions defined by Amazon Elastic Container Service.

To view examples of Amazon ECS identity-based policies, see Identity-based policy examples for Amazon Elastic Container Service.

Access control lists (ACLs) in Amazon ECS

Supports ACLs: No

Access control lists (ACLs) control which principals (account members, users, or roles) have permissions to access a resource. ACLs are similar to resource-based policies, although they do not use the JSON policy document format.

Attribute-based access control (ABAC) with Amazon ECS

Important

Amazon ECS supports attributes-based access control for all Amazon ECS resources. To determine whether you can use attributes to scope an action, use the Actions defined by Amazon ECS table in Service Authorization Reference. First verify that there is a resource in the Resource column. Then, use the Condition keys column to see the keys for the action/resource combination.

Supports ABAC (tags in policies): Yes

Attribute-based access control (ABAC) is an authorization strategy that defines permissions based on attributes. In AWS, these attributes are called tags. You can attach tags to IAM entities (users or roles) and to many AWS resources. Tagging entities and resources is the first step of ABAC. Then you design ABAC policies to allow operations when the principal's tag matches the tag on the resource that they are trying to access.

ABAC is helpful in environments that are growing rapidly and helps with situations where policy management becomes cumbersome.

To control access based on tags, you provide tag information in the condition element of a policy using the aws:ResourceTag/key-name, aws:RequestTag/key-name, or aws:TagKeys condition keys.

If a service supports all three condition keys for every resource type, then the value is Yes for the service. If a service supports all three condition keys for only some resource types, then the value is Partial.

For more information about ABAC, see What is ABAC? in the IAM User Guide. To view a tutorial with steps for setting up ABAC, see Use attribute-based access control (ABAC) in the IAM User Guide.

For more information about tagging Amazon ECS resources, see Tagging Amazon ECS resources.

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.

Using Temporary credentials with Amazon ECS

Supports temporary credentials: Yes

Some AWS services don't work when you sign in using temporary credentials. For additional information, including which AWS services work with temporary credentials, see AWS services that work with IAM in the IAM User Guide.

You are using temporary credentials if you sign in to the AWS Management Console using any method except a user name and password. For example, when you access AWS using your company's single sign-on (SSO) link, that process automatically creates temporary credentials. You also automatically create temporary credentials when you sign in to the console as a user and then switch roles. For more information about switching roles, see Switching to a role (console) in the IAM User Guide.

You can manually create temporary credentials using the AWS CLI or AWS API. You can then use those temporary credentials to access AWS. AWS recommends that you dynamically generate temporary credentials instead of using long-term access keys. For more information, see Temporary security credentials in IAM.

Forward access sessions for Amazon ECS

Supports forward access sessions (FAS): Yes

When you use an IAM user or role to perform actions in AWS, you are considered a principal. When you use some services, you might perform an action that then initiates another action in a different service. FAS uses the permissions of the principal calling an AWS service, combined with the requesting AWS service to make requests to downstream services. FAS requests are only made when a service receives a request that requires interactions with other AWS services or resources to complete. In this case, you must have permissions to perform both actions. For policy details when making FAS requests, see Forward access sessions.

Service roles for Amazon ECS

Supports service roles: Yes

A service role is an IAM role that a service assumes to perform actions on your behalf. An IAM administrator can create, modify, and delete a service role from within IAM. For more information, see Creating a role to delegate permissions to an AWS service in the IAM User Guide.

Warning

Changing the permissions for a service role might break Amazon ECS functionality. Edit service roles only when Amazon ECS provides guidance to do so.

Service-linked roles for Amazon ECS

Supports service-linked roles: Yes

A service-linked role is a type of service role that is linked to an AWS service. The service can assume the role to perform an action on your behalf. Service-linked roles appear in your AWS account and are owned by the service. An IAM administrator can view, but not edit the permissions for service-linked roles.

For details about creating or managing Amazon ECS service-linked roles, see Using service-linked roles for Amazon ECS.