Registering maintenance window tasks without targets
For each maintenance window you create, you can specify one or more tasks to perform when the maintenance window runs. In most cases, you must specify the resources, or targets, that the task is to run on. In some cases, however, you don't need to specify targets explicitly in the task.
One or more targets must be specified for maintenance window Systems Manager Run Command-type tasks. Depending on the nature of the task, targets are optional for other maintenance window task types (Systems Manager Automation, AWS Lambda, and AWS Step Functions).
For Lambda and Step Functions task types, whether a target is required depends on the content of the function or state machine you have created.
In many cases, you don't need to explicitly specify a target for an
automation task. For example, say that you're creating an Automation-type task to
update an Amazon Machine Image (AMI) for Linux
using the AWS-UpdateLinuxAmi runbook. When the task runs, the AMI is updated with the latest
available Linux distribution packages and Amazon software. New instances created from
the AMI already have these updates
installed. Because the ID of the AMI to be updated is specified in the input parameters for the runbook, there is no
need to specify a target again in the maintenance window task.
Similarly, suppose you're using the AWS Command Line Interface (AWS CLI) to register
a maintenance window
Automation task that uses the document AWS-RestartEC2Instance. Because the instance to restart
is specified in the --task-invocation-parameters argument, you don't need
to also specify a --targets option.
For maintenance window tasks without a target specified, you can't supply values
for --max-errors and --max-concurrency. Instead, the
system inserts a placeholder value of 1, which might be reported in the
response to commands such as describe-maintenance-window-tasks and
get-maintenance-window-task. These values don't affect the running
of your task and can be ignored.
The following example demonstrates omitting the
--targets,--max-errors, and --max-concurrency
options for a targetless maintenance window task.
For maintenance window tasks registered before December 23, 2020: If you specified targets for the task and one is no longer required, you can update that task to remove the targets using the Systems Manager console or the update-maintenance-window-task AWS CLI command.
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