Registering maintenance window tasks without targets
The ability to register tasks without targets is not currently supported in the AWS Systems Manager console.
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 do not 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.
Automation tasks more commonly don't need a target specified explicitly
for a task. For example, say that you are 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 are 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 cannot supply values
for --max-errors and --max-concurrency. Instead, the
system inserts a placeholder value of 1, which may be reported in the
response to commands such as describe-maintenance-window-tasks and
get-maintenance-window-task. These values do not 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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