====== On-Demand ======

**What it is:** Pay for compute resources by the second/minute/hour with no long-term commitment.

**What it’s for:**
  * Short-term, spiky, or unpredictable workloads.
  * Testing, dev environments, temporary projects.

**Key ideas:**
  * Highest flexibility, usually higher price than commitment models.

**Exam cues:**
  * “no commitment needed” → On-Demand.
  * “workload is unpredictable” → On-Demand (or Auto Scaling).

**Hard words:**
  * *commitment* /kəˈmɪtmənt/: cam kết
  * *spiky* /ˈspaɪki/: tăng vọt theo lúc
  * *unpredictable* /ˌʌnprɪˈdɪktəbl/: khó dự đoán