====== CloudWatch Logs ======

**What it is:** A service to collect, store, and search log data from AWS resources and applications.

**What it’s for:**
  * Centralize application/system logs.
  * Search logs to debug incidents.
  * Set metric filters and alerts from logs.

**Key ideas:**
  * Logs are stored in log groups and log streams.
  * You can set retention to control cost.
  * Integrates with Lambda and other services for automation.

**Exam cues:**
  * “store EC2 app logs centrally” → CloudWatch Logs (via agent).
  * “alert based on error pattern in logs” → metric filter + alarm.

**Hard words:**
  * *centralize* /ˈsentrəˌlaɪz/: tập trung hóa
  * *retention* /rɪˈtenʃn/: thời gian lưu giữ
  * *pattern* /ˈpætərn/: mẫu (chuỗi lỗi)