Working with shared parameters

Sharing advanced parameters simplifies configuration data management in a multi-account environment. You can centrally store and manage your parameters and share them with other AWS accounts that need to reference them.

Parameter Store integrates with AWS Resource Access Manager (AWS RAM) to enable advanced parameter sharing. AWS RAM is a service that enables you to share resources with other AWS accounts or through AWS Organizations.

With AWS RAM, you share resources that you own by creating a resource share. A resource share specifies the resources to share, permissions to grant, and the consumers with whom to share. Consumers can include:

• Specific AWS accounts inside or outside of its organization in AWS Organizations

• An organizational unit inside its organization in AWS Organizations

• Its entire organization in AWS Organizations

For more information about AWS RAM, see the AWS RAM User Guide.

This topic explains how to share parameters that you own, and how to use parameters that are shared with you.

Prerequisites for sharing parameters

The following prerequisites must be met before you can share parameters from your account:

• To share a parameter, you must own it in your AWS account. You can't share a parameter that has been shared with you.

• To share a parameter, it must be in the advanced parameter tier. For information about parameter tiers, see Managing parameter tiers. For information about changing an existing standard parameter to an advanced parameter, see Changing a standard parameter to an advanced parameter.

• To share a SecureString parameter, it must be encrypted with a customer managed key, and you must share the key separately through AWS Key Management Service. AWS managed keys cannot be shared. Parameters encrypted with the default AWS managed key can be updated to use a customer managed key instead. For AWS KMS key definitions, see AWS KMS concepts in the AWS Key Management Service Developer Guide.

• To share a parameter with your organization or an organizational unit in AWS Organizations, you must enable sharing with AWS Organizations. For more information, see Enable Sharing with AWS Organizations in the AWS RAM User Guide.

Sharing a parameter

To share a parameter, you must add it to a resource share. A resource share is an AWS RAM resource that lets you share your resources across AWS accounts. A resource share specifies the resources to share, and the consumers with whom they are shared.

When you share a parameter that you own with other AWS accounts, you can choose from two AWS managed permissions to grant the consumers. For more information, see Permissions sets for sharing parameters.

If you are part of an organization in AWS Organizations and sharing within your organization is enabled, you can grant consumers in your organization access from the AWS RAM console to the shared parameter. Otherwise, consumers receive an invitation to join the resource share and are granted access to the shared parameter after accepting the invitation.

You can share a parameter that you own using the AWS RAM console, or the AWS CLI.

Note

While you can share a parameter using the Systems Manager PutResourcePolicy API operation, we recommend using AWS Resource Access Manager (AWS RAM) instead. This is because using PutResourcePolicy requires the extra step of promoting the parameter to a standard Resource Share using the AWS RAM PromoteResourceShareCreatedFromPolicy API operation. Otherwise, the parameter won't be returned by the Systems Manager DescribeParameters API operation using the --shared option.

To share a parameter that you own using the AWS RAM console

See Creating a resource share in AWS RAM in the AWS RAM User Guide.

Make the following selections as you complete the procedure:

• In the Step 1 page, for Resources, select Parameter Store Advanced Parameter, and then select the box of each parameter in the advanced parameter tier that you want to share.

• In the Step 2 page, for Managed permissions, choose the permission to grant consumers, as described in Permissions sets for sharing parameters later in this topic.

Choose oher options based on your parameter sharing objectives.

To share a parameter that you own using the AWS CLI

Use the create-resource-share command to add parameters to a new resource share.

Use the associate-resource-share command to add parameters to an existing resource share.

The following example creates a new resource share to share parameters with consumers in an organization and in an individual account.

aws ram create-resource-share \
    --name "MyParameter" \
    --resource-arns "arn:aws:ssm:us-east-2:123456789012:parameter/MyParameter" \
    --principals "arn:aws:organizations::123456789012:ou/o-63bEXAMPLE/ou-46xi-rEXAMPLE" "987654321098"

Stop sharing a shared parameter

When you stop sharing a shared parameter, the consumer account can no longer access the parameter.

To stop sharing a parameter that you own, you must remove it from the resource share. You can do this using the Systems Manager console, AWS RAM console, or the AWS CLI.

To stop sharing a parameter that you own using the AWS RAM console

See Update a resource share in AWS RAM in the AWS RAM User Guide.

To stop sharing a parameter that you own using the AWS CLI

Use the disassociate-resource-share command.

Identifying shared parameters

Owners and consumers can identify shared parameters using the AWS CLI.

To identify shared parameters using the AWS CLI

To identify shared parameters using the AWS CLI, you can choose from the Systems Manager describe-parameters command and the AWS RAM list-resources command.

When you use the --shared option with describe-parameters, the command returns the parameters that are shared with you.

The following is an example:

aws ssm describe-parameters --shared

Accessing shared parameters

Consumers can access shared parameters using the AWS command line tools, and AWS SDKs. For consumer accounts, parameters shared with that account aren't included in the My parameters page.

CLI Example: Accessing shared parameter details using the AWS CLI

To access shared parameter details using the AWS CLI, you can use the get-parameter or get-parameters commands. You must specify the full parameter ARN as the --name in order to retrieve the parameter from another account.

The following is an example.

aws ssm get-parameter \
    --name arn:aws:ssm:us-east-2:123456789012:parameter/MySharedParameter

Supported and unsupported integrations for shared parameters

Currently, you can use shared parameters in the following integration scenarios:

• AWS CloudFormation template parameters

• The AWS Parameters and Secrets Lambda extension

• Amazon Elastic Compute Cloud (EC2) launch templates

• Values for ImageID with the EC2 RunInstances command to create instances from an Amazon Machine Image (AMI)

• Retrieving parameter values in runbooks for Automation, a capability of Systems Manager

The following scenarios and integrated services do not currently support the use of shared parameters:

• Parameters in commands in Run Command, a capability of Systems Manager

• AWS CloudFormation dynamic references

• The values of environment variables in AWS CodeBuild

• The values of environment variables in AWS App Runner

• The value of a secret in Amazon Elastic Container Service

Permissions sets for sharing parameters

Consumer accounts receive read-only access to the parameters you share with them. The consumer can't update or delete the parameter. The consumer can't share the parameter with a third account.

When you create a resource share in AWS Resource Access Manager for sharing your parameters, you can choose from two AWS managed permission sets to grant this read-only access:

AWSRAMDefaultPermissionSSMParameterReadOnly

Allowed actions: DescribeParameters, GetParameter, GetParameters

AWSRAMPermissionSSMParameterReadOnlyWithHistory

Allowed actions: DescribeParameters, GetParameter, GetParameters, GetParameterHistory

When you folllow the steps in Creating a resource share in AWS RAM in the AWS RAM User Guide, choose Parameter Store Advanced Parameters as the resource type and either of these managed permissions, depending on whether you want users to view parameter history or not.

Maximum throughput for shared parameters

Systems Manager limits the maximum throughput (transactions per second) for the GetParameter and GetParameters. operations. Throughput is enforced at the individual account level. Therefore, each account that consumes a shared parameter can use its maximum allowed throughput without being affected by other accounts. For more information about maximum throughput for parameters, see the following topics:

• Increasing Parameter Store throughput

• Systems Manager Service quotas in the Amazon Web Services General Reference.

Pricing for shared parameters

Cross-account sharing is only available in the advanced parameter tier. For advanced parameters, charges are incurred at the current price for the storage and API usage for each advanced parameter. The owning account is charged for storage of the advanced parameter. Any consuming account that makes an API call to a shared advanced parameter is charged for the parameter usage.

For example, if Account A creates an advanced parameter, MyAdvancedParameter, that account is charged USD 0.05 per month to store the parameter.

Account A then shares MyAdvancedParameter with Account B and Account C. During a month, the three accounts make calls to MyAdvancedParameter. The following table illustrates the charges they would incur for the number of calls each makes.

Note

The charges in the following table are for illustration only. To verify current pricing, see AWS Systems Manager Pricing for Parameter Store.

Account	Number of calls	Charges
Account A (owning account)	10,000 calls	One month advanced parameter storage: USD 0.05 10,000 calls to MyAdvancedParameter: USD 0.05 Total: USD 0.10
Account B (consuming account)	20,000 calls	20,000 calls to MyAdvancedParameter: USD 0.10 Total: USD 0.10
Account C (consuming account)	30,000 calls	30,000 calls to MyAdvancedParameter: USD 0.15 Total: USD 0.15

Cross-account access for closed AWS accounts

If the AWS account that owns a shared parameter is closed, all consuming accounts lose access to the shared parameter. If the owning account is reopened within 90 days after the account is closed, consuming accounts regain access to the previously shared parameters. For more information about reopening an account during the Post-Closure Period, see Accessing your AWS account after you close it in the AWS Account Management Reference Guide.