200-901 Application Deployment and Security Practice Question
In a Docker Compose file with multiple services, one service depends on another to be healthy before starting. Which key should be used to express this dependency and ensure the dependent service is started first?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
depends_on
depends_on in Docker Compose controls startup order. 'links' is legacy, 'networks' defines networks, 'volumes' mounts volumes.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
depends_on
Why this is correct
depends_on ensures services start in order.
- ✗
volumes
Why it's wrong here
volumes mount storage.
- ✗
networks
Why it's wrong here
networks connect services to networks.
- ✗
links
Why it's wrong here
The `links` key only establishes network connectivity between containers and a startup order based on service name, not a health check. It fails because the stem requires the dependent service to wait until the other service is *healthy*, not merely started. This option is tempting because `links` does guarantee that the linked container starts first, which matches a common misinterpretation of "depends on" as simple sequential startup rather than health-dependent readiness.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-901 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 200-901 exam.