Patching managed nodes on demand - Amazon Systems Manager
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Patching managed nodes on demand

Using the Patch now option in Patch Manager, a capability of Amazon Systems Manager, you can run on-demand patching operations from the Systems Manager console. This means you don’t have to create a schedule in order to update the compliance status of your managed nodes or to install patches on noncompliant nodes. You also don’t need to switch the Systems Manager console between Patch Manager and Maintenance Windows, a capability of Amazon Systems Manager, in order to set up or modify a scheduled patching window.

Patch now is especially useful when you must apply zero-day updates or install other critical patches on your managed nodes as soon as possible.


Patching on demand is supported for a single Amazon Web Services account-Amazon Web Services Region pair at a time. It can't be used with patching operations that are based on patch policies. We recommend using patch policies for keeping all your managed nodes in compliance. For more information about working with patch policies, see Using Quick Setup patch policies.

How 'Patch now' works

To run Patch now, you specify just two required settings:

  • Whether to scan for missing patches only, or to scan and install patches on your managed nodes

  • Which managed nodes to run the operation on

When the Patch now operation runs, it determines which patch baseline to use in the same way one is selected for other patching operations. If a managed node is associated with a patch group, the patch baseline specified for that group is used. If the managed node isn't associated with a patch group, the operation uses the patch baseline that is currently set as the default for the operating system type of the managed node. This can be a predefined baseline, or the custom baseline you have set as the default. For more information about patch baseline selection, see About patch groups.

Options you can specify for Patch now include choosing when, or whether, to reboot managed nodes after patching, specifying an Amazon Simple Storage Service (Amazon S3) bucket to store log data for the patching operation, and running Systems Manager documents (SSM documents) as lifecycle hooks during patching.

Concurrency and error thresholds for 'Patch now'

For Patch now operations, concurrency and error threshold options are handled by Patch Manager. You don't need to specify how many managed nodes to patch at once, nor how many errors are permitted before the operation fails. Patch Manager applies the concurrency and error threshold settings described in the following tables when you patch on demand.


The following thresholds apply to Scan and install operations only. For Scan operations, Patch Manager attempts to scan up to 1,000 nodes concurrently, and continue scanning until it has encountered up to 1,000 errors.

Concurrency: Install operations
Total number of managed nodes in the Patch now operation Number of managed nodes scanned or patched at a time
Fewer than 25 1
25-100 5%
101 to 1,000 8%
More than 1,000 10%
Error threshold: Install operations
Total number of managed nodes in the Patch now operation Number of errors permitted before the operation fails
Fewer than 25 1
25-100 5
101 to 1,000 10
More than 1,000 10

Using 'Patch now' lifecycle hooks

Patch now provides you with the ability to run SSM Command documents as lifecycle hooks during an Install patching operation. You can use these hooks for tasks such as shutting down applications before patching or running health checks on your applications after patching or after a reboot.

For more information about using lifecycle hooks, see About the AWS-RunPatchBaselineWithHooks SSM document.

The following table lists the lifecycle hooks available for each of the three Patch now reboot options, in addition to sample uses for each hook.

Lifecycle hooks and sample uses
Reboot option Hook: Before installation Hook: After installation Hook: On exit Hook: After scheduled reboot
Reboot if needed

Run an SSM document before patching begins.

Example use: Safely shut down applications before the patching process begins.

Run an SSM document at the end of the patching operation and before managed node reboot.

Example use: Run operations such as installing third-party applications before a potential reboot.

Run an SSM document after the patching operation is complete and instances are rebooted.

Example use: Ensure that applications are running as expected after patching.

Not available
Do not reboot my instances Same as above.

Run an SSM document at the end of the patching operation.

Example use: Ensure that applications are running as expected after patching.

Not available

Not available

Schedule a reboot time Same as above. Same as for Do not reboot my instances. Not available

Run an SSM document immediately after a scheduled reboot is complete.

Example use: Ensure that applications are running as expected after the reboot.

Running 'Patch now'

Use the following procedure to patch your managed nodes on demand.

To run 'Patch now'
  1. Open the Amazon Systems Manager console at

  2. In the navigation pane, choose Patch Manager.

  3. On either the Amazon Systems Manager Patch Manager page or the Patch baselines page, depending on which one opens, choose Patch now.

  4. For Patching operation, choose one of the following:

    • Scan: Patch Manager finds which patches are missing from your managed nodes but doesn't install them. You can view the results in the Compliance dashboard or in other tools you use for viewing patch compliance.

    • Scan and install: Patch Manager finds which patches are missing from your managed nodes and installs them.

  5. Use this step only if you chose Scan and install in the previous step. For Reboot option, choose one of the following:

    • Reboot if needed: After installation, Patch Manager reboots managed nodes only if needed to complete a patch installation.

    • Don't reboot my instances: After installation, Patch Manager doesn't reboot managed nodes. You can reboot nodes manually when you choose or manage reboots outside of Patch Manager.

    • Schedule a reboot time: Specify the date, time, and UTC time zone for Patch Manager to reboot your managed nodes. After you run the Patch now operation, the scheduled reboot is listed as an association in State Manager with the name AWS-PatchRebootAssociation.

  6. For Instances to patch, choose one of the following:

    • Patch all instances: Patch Manager runs the specified operation on all managed nodes in your Amazon Web Services account in the current Amazon Web Services Region.

    • Patch only the target instances I specify: You specify which managed nodes to target in the next step.

  7. Use this step only if you chose Patch only the target instances I specify in the previous step. In the Target selection section, identify the nodes on which you want to run this operation by specifying tags, selecting nodes manually, or specifying a resource group.


    If a managed node you expect to see isn't listed, see Troubleshooting managed node availability for troubleshooting tips.

    If you choose to target a resource group, note that resource groups that are based on an Amazon CloudFormation stack must still be tagged with the default aws:cloudformation:stack-id tag. If it has been removed, Patch Manager might be unable to determine which managed nodes belong to the resource group.

  8. (Optional) For Patching log storage, if you want to create and save logs from this patching operation, select the S3 bucket for storing the logs.


    The S3 permissions that grant the ability to write the data to an S3 bucket are those of the instance profile (for EC2 instances) or IAM service role (hybrid-activated machines) assigned to the instance, not those of the IAM user performing this task. For more information, see Configure instance permissions for Systems Manager or Create an IAM service role for a hybrid environment. In addition, if the specified S3 bucket is in a different Amazon Web Services account, make sure that the instance profile or IAM service role associated with the managed node has the necessary permissions to write to that bucket.

  9. (Optional) If you want to run SSM documents as lifecycle hooks during specific points of the patching operation, do the following:

    • Choose Use lifecycle hooks.

    • For each available hook, select the SSM document to run at the specified point of the operation:

      • Before installation

      • After installation

      • On exit

      • After scheduled reboot


      The default document, AWS-Noop, runs no operations.

  10. Choose Patch now.

    The Association execution summary page opens. (Patch now uses associations in State Manager, a capability of Amazon Systems Manager, for its operations.) In the Operation summary area, you can monitor the status of scanning or patching on the managed nodes you specified.