The primary focus of Patch Manager, a capability of AWS Systems Manager, is on installing operating systems security-related updates on managed nodes. By default, Patch Manager doesn't install all available patches, but rather a smaller set of patches focused on security. (Ref https://docs.aws.amazon.com/systems-manager/latest/userguide/patch-manager-how-it-works-selection.html) Run Command allows you to automate common administrative tasks and perform one-time configuration changes at scale. (Ref https://docs.aws.amazon.com/systems-manager/latest/userguide/execute-remote-commands.html) Seems like patch manager is meant for OS level patches and not 3rd party applications. And this falls under run command wheelhouse to carry out one-time configuration changes (update of 3rd part application) at scale.

D AWS Systems Manager Run Command allows the company to run commands or scripts on multiple EC2 instances. By using Run Command, the company can quickly and easily apply the patch to all 1,000 EC2 instances to remediate the security vulnerability. Creating an AWS Lambda function to apply the patch to all EC2 instances would not be a suitable solution, as Lambda functions are not designed to run on EC2 instances. Configuring AWS Systems Manager Patch Manager to apply the patch to all EC2 instances would not be a suitable solution, as Patch Manager is not designed to apply third-party software patches. Scheduling an AWS Systems Manager maintenance window to apply the patch to all EC2 instances would not be a suitable solution, as maintenance windows are not designed to apply patches to third-party software

Install software -> Patch Manager Run command/processing workload -> Run Command

I think patch manager would need an agent to be installed and also Patch Manager doesn't derive severity levels from third-party sources.

AWS Systems Manager Patch Manager primarily focuses on operating system patches and does not directly support third-party software patching on Linux instances

Critical means immediate. Just run the patch command with AWS SM run command to get it done. D is best choice. A: Too convoluted B: Can work but have to setup a lot of things to get this done. would be a good choice if D wasn't an option C: It's a critical patch so not time for maintenance window

By practice, isn't schedule planned downtime is common sense before patching done?

maintenance window will trigger the run command or the patch manager in the right time (as quickly as possible )

keyword - as quickly as possible Option B - efficient and reliable Option D - speed and immediate execution hence D is correct

Third party software - Custom command.

D - Patch manager does not understand severity for third party software . Patch Manager doesn't derive severity levels from third-party sources, such as the Common Vulnerability Scoring System (CVSS), or from metrics released by the National Vulnerability Database (NVD). https://docs.aws.amazon.com/systems-manager/latest/userguide/patch-manager.html

I go with option B. To quickly patch third-party software on 1,000 EC2 instances, use AWS Systems Manager Patch Manager. It automates the patching process, from scanning for missing patches to applying the patch to all targeted instances. Patch Manager is designed for managing and automating the patching process for EC2 instances at scale.

Key: third-party software and run custom command

Hey dudes. Patch Manager needs the agent. You have to install the agent on all of instances. Can you install the agent over a thousand? Maybe you need SSM Run Command. https://docs.aws.amazon.com/systems-manager/latest/userguide/patch-manager-prerequisites.html

Make note of this requirement, "as quickly as possible to remediate a critical security vulnerability." Patch Manager would save time and effort.

Patching support for applications on Windows Server managed nodes is limited to applications released by Microsoft. https://docs.aws.amazon.com/systems-manager/latest/userguide/patch-manager-patching-windows-applications.html

AWS Systems Manager Patch Manager is designed to apply patches not only to the operating system but also to third-party software running on Amazon EC2 instances, on-premises servers, and virtual machines. It allows you to manage and automate the process of patching both operating systems and applications, including third-party applications so using the patch manager and scheduling a maintenance window, you can ensure controlled and coordinated patching of the EC2 instances. This helps in minimizing disruptions and managing the process effectivel so the answer is C :)