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Automation assume role - AWS Systems Manager

Automation assume role

The automation assume role is the role Automation assumes when it runs the runbook that onboards a GCP virtual machine as a managed node. The role can call the core Systems Manager APIs needed for hybrid activation. It can also pass a service role to Systems Manager and assume the GCP federation role to obtain GCP credentials.

Role name pattern: SSM-GCPAssumeRole-connector-name

The trust policy lets the Systems Manager service principal assume the role, scoped to your AWS account. Replace 123456789012 with your AWS account ID.

{
    "Version": "2012-10-17", 
    "Statement": [
        {
            "Effect": "Allow",
            "Action": "sts:AssumeRole",
            "Principal": {
                "Service": "ssm.amazonaws.com"
            },
            "Condition": {
                "StringEquals": {
                    "aws:SourceAccount": "123456789012"
                }
            }
        }
    ]
}

The permissions policy grants the actions Automation needs to execute the onboarding runbooks. Replace 123456789012 with your AWS account ID, us-east-1 with the AWS Region that the Cloud Connector is created in, SSM-GCPRole-MyConnector with the name of the GCP federation role, SSM-GCPAssumeRole-MyConnector with the name of the automation assume role, AmazonEC2RunCommandRoleForManagedInstances with the name of the managed instance role attached to the Cloud Connector, and connector-id with the ID of the Cloud Connector.

Permissions details

This policy includes the following permissions:

  • ssm – Allows Automation to create, delete, and describe hybrid activations (CreateActivation, DeleteActivation, DescribeActivations); to register GCP virtual machines as managed nodes and read their status (DescribeInstanceInformation); to tag activations and managed instances (AddTagsToResource); to read the installation runbook and its child runbooks (GetDocument); and to read the Cloud Connector configuration (GetCloudConnector).

  • iam:PassRole – Allows Automation to pass the managed instance role to Systems Manager when registering a GCP virtual machine, and to pass the automation assume role to Automation when it starts a runbook execution. The iam:PassedToService condition restricts both passes to ssm.amazonaws.com. The iam:AssociatedResourceARN condition restricts the automation assume role pass to the AWS-InstallSSMAgentOnGCP runbook, its three child runbooks, and automation executions in the connector's AWS Region.

  • iam:ListRoleTags – Allows Automation to read tags on the GCP federation role to confirm it belongs to the same Cloud Connector before assuming it.

  • sts:AssumeRole – Allows Automation to assume the GCP federation role to obtain GCP credentials.

  • ssm:StartAutomationExecution and ssm:GetAutomationExecution – Allows Automation to start and monitor executions of the AWS-InstallSSMAgentOnGCP runbook and its three child runbooks (AWS-InstallSSMAgentOnGCP-SetupAndActivation, AWS-InstallSSMAgentOnGCP-ApplyOSPolicy, and AWS-InstallSSMAgentOnGCP-VerifyVMStatus) in the connector's AWS Region.

{
    "Version": "2012-10-17", 
    "Statement": [
        {
            "Effect": "Allow",
            "Action": "sts:AssumeRole",
            "Resource": "arn:aws:iam::123456789012:role/service-role/SSM-GCPRole-MyConnector"
        },
        {
            "Effect": "Allow",
            "Action": "iam:PassRole",
            "Resource": "arn:aws:iam::123456789012:role/service-role/AmazonEC2RunCommandRoleForManagedInstances",
            "Condition": {
                "StringEquals": {
                    "iam:PassedToService": "ssm.amazonaws.com"
                }
            }
        },
        {
            "Effect": "Allow",
            "Action": "iam:PassRole",
            "Resource": "arn:aws:iam::123456789012:role/service-role/SSM-GCPAssumeRole-MyConnector",
            "Condition": {
                "StringEquals": {
                    "iam:PassedToService": "ssm.amazonaws.com"
                },
                "ArnLike": {
                    "iam:AssociatedResourceARN": [
                        "arn:aws:ssm:us-east-1::document/AWS-InstallSSMAgentOnGCP",
                        "arn:aws:ssm:us-east-1::automation-definition/AWS-InstallSSMAgentOnGCP:$DEFAULT",
                        "arn:aws:ssm:us-east-1::document/AWS-InstallSSMAgentOnGCP-SetupAndActivation",
                        "arn:aws:ssm:us-east-1::automation-definition/AWS-InstallSSMAgentOnGCP-SetupAndActivation:$DEFAULT",
                        "arn:aws:ssm:us-east-1::document/AWS-InstallSSMAgentOnGCP-ApplyOSPolicy",
                        "arn:aws:ssm:us-east-1::automation-definition/AWS-InstallSSMAgentOnGCP-ApplyOSPolicy:$DEFAULT",
                        "arn:aws:ssm:us-east-1::document/AWS-InstallSSMAgentOnGCP-VerifyVMStatus",
                        "arn:aws:ssm:us-east-1::automation-definition/AWS-InstallSSMAgentOnGCP-VerifyVMStatus:$DEFAULT",
                        "arn:aws:ssm:us-east-1:123456789012:automation-execution/*"
                    ]
                }
            }
        },
        {
            "Effect": "Allow",
            "Action": [
                "ssm:CreateActivation",
                "ssm:DeleteActivation",
                "ssm:DescribeActivations",
                "ssm:DescribeInstanceInformation",
                "iam:ListRoleTags",
                "ssm:AddTagsToResource"
            ],
            "Resource": "*"
        },
        {
            "Effect": "Allow",
            "Action": "ssm:GetDocument",
            "Resource": [
                "arn:aws:ssm:us-east-1::document/AWS-InstallSSMAgentOnGCP",
                "arn:aws:ssm:us-east-1::automation-definition/AWS-InstallSSMAgentOnGCP:$DEFAULT",
                "arn:aws:ssm:us-east-1::document/AWS-InstallSSMAgentOnGCP-SetupAndActivation",
                "arn:aws:ssm:us-east-1::automation-definition/AWS-InstallSSMAgentOnGCP-SetupAndActivation:$DEFAULT",
                "arn:aws:ssm:us-east-1::document/AWS-InstallSSMAgentOnGCP-ApplyOSPolicy",
                "arn:aws:ssm:us-east-1::automation-definition/AWS-InstallSSMAgentOnGCP-ApplyOSPolicy:$DEFAULT",
                "arn:aws:ssm:us-east-1::document/AWS-InstallSSMAgentOnGCP-VerifyVMStatus",
                "arn:aws:ssm:us-east-1::automation-definition/AWS-InstallSSMAgentOnGCP-VerifyVMStatus:$DEFAULT"
            ]
        },
        {
            "Effect": "Allow",
            "Action": [
                "ssm:StartAutomationExecution",
                "ssm:GetAutomationExecution"
            ],
            "Resource": [
                "arn:aws:ssm:us-east-1::document/AWS-InstallSSMAgentOnGCP",
                "arn:aws:ssm:us-east-1::automation-definition/AWS-InstallSSMAgentOnGCP:$DEFAULT",
                "arn:aws:ssm:us-east-1::document/AWS-InstallSSMAgentOnGCP-SetupAndActivation",
                "arn:aws:ssm:us-east-1::automation-definition/AWS-InstallSSMAgentOnGCP-SetupAndActivation:$DEFAULT",
                "arn:aws:ssm:us-east-1::document/AWS-InstallSSMAgentOnGCP-ApplyOSPolicy",
                "arn:aws:ssm:us-east-1::automation-definition/AWS-InstallSSMAgentOnGCP-ApplyOSPolicy:$DEFAULT",
                "arn:aws:ssm:us-east-1::document/AWS-InstallSSMAgentOnGCP-VerifyVMStatus",
                "arn:aws:ssm:us-east-1::automation-definition/AWS-InstallSSMAgentOnGCP-VerifyVMStatus:$DEFAULT",
                "arn:aws:ssm:us-east-1:123456789012:automation-execution/*"
            ]
        },
        {
            "Effect": "Allow",
            "Action": "ssm:GetCloudConnector",
            "Resource": "arn:aws:ssm:us-east-1:123456789012:cloud-connector/connector-id"
        }
    ]
}