What it is: A blueprint describing how to run containers (image, CPU/memory, ports, env vars, IAM role, logging).

What it’s for:

• Define container runtime settings consistently.
• Version and update deployments.

Key ideas:

• Includes:
  • container image (often from ECR)
  • resource limits
  • networking mode
  • task role (permissions)
• New revision is created when you update it.

Exam cues:

• “define container settings and resources” → task definition.

Hard words:

• *blueprint* /ˈbluːprɪnt/: bản thiết kế
• *revision* /rɪˈvɪʒn/: bản sửa/phiên bản