• The AWS Systems Manager CloudWatch Dashboard will no longer be available after April 30, 2026. Customers can continue to use Amazon CloudWatch console to view, create, and manage their Amazon CloudWatch dashboards, just as they do today. For more information, see [Amazon CloudWatch Dashboard documentation](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/CloudWatch_Dashboards.html). 

# Using pseudo parameters when registering maintenance window tasks


When you register a task in Maintenance Windows, a tool in AWS Systems Manager, you specify the parameters that are unique to each of the four task types. (In CLI commands, these are provided using the `--task-invocation-parameters` option.)

 You can also reference certain values using *pseudo parameter* syntax, such as `{{RESOURCE_ID}}`, `{{TARGET_TYPE}}`, and `{{WINDOW_TARGET_ID}}`. When the maintenance window task runs, it passes the correct values instead of the pseudo parameter placeholders. The full list of pseudo parameters you can use is provided later in this topic in [Supported pseudo parameters](#pseudo-parameters).

**Important**  
For the target type `RESOURCE_GROUP`, depending on the ID format needed for the task, you can choose between using `{{TARGET_ID}}` and `{{RESOURCE_ID}}` to reference the resource when your task runs. `{{TARGET_ID}}` returns the full ARN of the resource. `{{RESOURCE_ID}}` returns only a shorter name or ID of the resource, as shown in these examples.  
`{{TARGET_ID}}` format: `arn:aws:ec2:us-east-1:123456789012:instance/i-02573cafcfEXAMPLE`
`{{RESOURCE_ID}}` format: `i-02573cafcfEXAMPLE`
For target type `INSTANCE`, both the `{{TARGET_ID}}` and `{{RESOURCE_ID}}` parameters yield the instance ID only. For more information, see [Supported pseudo parameters](#pseudo-parameters).  
`{{TARGET_ID}}` and `{{RESOURCE_ID}}` can be used to pass IDs of AWS resources only to Automation, Lambda, and Step Functions tasks. These two pseudo parameters can't be used with Run Command tasks.

## Pseudo parameter examples


Suppose that your payload for an AWS Lambda task needs to reference an instance by its ID.

Whether you’re using an `INSTANCE` or a `RESOURCE_GROUP` maintenance window target, this can be achieved by using the `{{RESOURCE_ID}}` pseudo parameter. For example:

```
"TaskArn": "arn:aws:lambda:us-east-2:111122223333:function:SSMTestFunction",
    "TaskType": "LAMBDA",
    "TaskInvocationParameters": {
        "Lambda": {
            "ClientContext": "ew0KICAi--truncated--0KIEXAMPLE",
            "Payload": "{ \"instanceId\": \"{{RESOURCE_ID}}\" }",
            "Qualifier": "$LATEST"
        }
    }
```

If your Lambda task is intended to run against another supported target type in addition to Amazon Elastic Compute Cloud (Amazon EC2) instances, such as an Amazon DynamoDB table, the same syntax can be used, and `{{RESOURCE_ID}}` yields the name of the table only. However, if you require the full ARN of the table, use `{{TARGET_ID}}`, as shown in the following example.

```
"TaskArn": "arn:aws:lambda:us-east-2:111122223333:function:SSMTestFunction",
    "TaskType": "LAMBDA",
    "TaskInvocationParameters": {
        "Lambda": {
            "ClientContext": "ew0KICAi--truncated--0KIEXAMPLE",
            "Payload": "{ \"tableArn\": \"{{TARGET_ID}}\" }",
            "Qualifier": "$LATEST"
        }
    }
```

The same syntax works for targeting instances or other resource types. When multiple resource types have been added to a resource group, the task runs against each of the appropriate resources. 

**Important**  
Not all resource types that might be included in a resource group yield a value for the `{{RESOURCE_ID}}` parameter. For a list of supported resource types, see [Supported pseudo parameters](#pseudo-parameters).

As another example, to run an Automation task that stops your EC2 instances, you specify the `AWS-StopEC2Instance` Systems Manager document (SSM document) as the `TaskArn` value and use the `{{RESOURCE_ID}}` pseudo parameter:

```
"TaskArn": "AWS-StopEC2Instance",
    "TaskType": "AUTOMATION"
    "TaskInvocationParameters": {
        "Automation": {
            "DocumentVersion": "1",
            "Parameters": {
                "instanceId": [
                    "{{RESOURCE_ID}}"
                ]
            }
        }
    }
```

To run an Automation task that copies a snapshot of an Amazon Elastic Block Store (Amazon EBS) volume, you specify the `AWS-CopySnapshot` SSM document as the `TaskArn` value and use the `{{RESOURCE_ID}}` pseudo parameter.

```
"TaskArn": "AWS-CopySnapshot",
    "TaskType": "AUTOMATION"
    "TaskInvocationParameters": {
        "Automation": {
            "DocumentVersion": "1",
            "Parameters": {
                "SourceRegion": "us-east-2",
                "targetType":"RESOURCE_GROUP",
                "SnapshotId": [
                    "{{RESOURCE_ID}}"
                ]
            }
        }
    }
```

## Supported pseudo parameters


The following list describes the pseudo parameters that you can specify using the `{{PSEUDO_PARAMETER}}` syntax in the `--task-invocation-parameters` option.
+ **`WINDOW_ID`**: The ID of the target maintenance window.
+ **`WINDOW_TASK_ID`**: The ID of the window task that is running.
+ **`WINDOW_TARGET_ID`**: The ID of the window target that includes the target (target ID).
+ **`WINDOW_EXECUTION_ID`**: The ID of the current window execution.
+ **`TASK_EXECUTION_ID`**: The ID of the current task execution.
+ **`INVOCATION_ID`**: The ID of the current invocation.
+ **`TARGET_TYPE`**: The type of target. Supported types include `RESOURCE_GROUP` and `INSTANCE`.
+ **`TARGET_ID`**: 

  If the target type you specify is `INSTANCE`, the `TARGET_ID` pseudo parameter is replaced by the ID of the instance. For example, `i-078a280217EXAMPLE`.

  If the target type you specify is `RESOURCE_GROUP`, the value referenced for the task execution is the full ARN of the resource. For example: `arn:aws:ec2:us-east-1:123456789012:instance/i-078a280217EXAMPLE`. The following table provides sample `TARGET_ID` values for particular resource types in a resource group. 
**Note**  
`TARGET_ID` isn't supported for Run Command tasks.    
[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/systems-manager/latest/userguide/maintenance-window-tasks-pseudo-parameters.html)
+ **`RESOURCE_ID`**: The short ID of a resource type contained in a resource group. The following table provides sample `RESOURCE_ID` values for particular resource types in a resource group. 
**Note**  
`RESOURCE_ID` isn't supported for Run Command tasks.    
[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/systems-manager/latest/userguide/maintenance-window-tasks-pseudo-parameters.html)
**Note**  
If the AWS resource group you specify includes resource types that don't yield a `RESOURCE_ID` value, and aren't listed in the preceding table, then the `RESOURCE_ID` parameter isn't populated. An execution invocation will still occur for that resource. In these cases, use the `TARGET_ID` pseudo parameter instead, which will be replaced with the full ARN of the resource.