Reserved Instances (RI)

What it is: A commitment-based discount model for EC2 (and some other services) for 1 or 3 years.

What it’s for:

• Save money for steady-state, predictable workloads.

Key ideas (exam-friendly):

• You commit to a term (1 or 3 years).
• Lower cost than On-Demand.
• Best when capacity needs are stable.

Exam cues:

• “steady usage for 1 year, want lower cost” → RI.

Hard words:

• *term* /tɝːrm/: kỳ hạn
• *steady-state* /ˈstedi steɪt/: ổn định
• *capacity* /kəˈpæsəti/: năng lực tài nguyên