====== Patch Manager ======

**What it is:** An SSM feature to automate OS patching for managed instances.

**What it’s for:**
  * Apply security updates consistently across a fleet.
  * Reduce vulnerability exposure over time.

**Key ideas:**
  * You define patch baselines and maintenance windows.
  * Works with compliance reporting.

**Exam cues:**
  * “automate patching weekly” → Patch Manager + maintenance window.

**Hard words:**
  * *vulnerability* /ˌvʌlnərəˈbɪləti/: lỗ hổng
  * *baseline* /ˈbeɪslaɪn/: chuẩn nền (rule chuẩn)
  * *maintenance window* /ˈmeɪntənəns ˈwɪndoʊ/: khung giờ bảo trì