3.1.4. Systems Manager Patch Manager for OS Patching

💡 First Principle: Systems Manager Patch Manager automates the process of patching operating systems and applications across EC2 instances and on-premises servers, ensuring security updates are consistently applied and reducing vulnerabilities at scale.

Scenario: Your organization needs to ensure all production EC2 instances are regularly updated with the latest security patches for their operating systems, but these patches must be applied during specific maintenance windows to minimize disruption. Manually patching hundreds of instances is inefficient and inconsistent.

For SysOps Administrators, keeping servers patched with the latest security updates is a critical, yet often complex and time-consuming, operational task. AWS Systems Manager Patch Manager simplifies and automates this process.

Key Features of Systems Manager Patch Manager:

• Automated Patching: Automates the application of patches for supported operating systems (Windows, Linux) and applications.
• Patch Baselines: (Define which patches are approved for deployment, which are rejected, and acceptable severity levels.) You can define custom patch baselines to control which patches are approved or rejected.
• Scheduling: Apply patches on a defined schedule (e.g., weekly, monthly during maintenance windows) using Systems Manager Automation.
• Compliance Reporting: Provides reports on patch compliance across your instances, showing which instances are missing patches and which patches are missing.
• Reboot Control: Manage when instances are rebooted during patching to minimize disruption.

⚠️ Common Pitfall: Not defining appropriate patch baselines, leading to either unapproved patches being installed or critical patches being missed.

Key Trade-Offs: Automated, scheduled patching (Patch Manager) versus manual patching (time-consuming, inconsistent, higher risk).

Reflection Question: How does Systems Manager Patch Manager, by automating the process of patching operating systems and applications (using patch baselines and scheduled deployments), fundamentally ensure security updates are consistently applied and reduce vulnerabilities at scale?