Docker and CI/CD · Junior · Question 9 of 75

Does `EXPOSE 3000` in a Dockerfile make the port reachable from the host?

✓Correct answer: No, it only documents the port; publish it with -p
2Yes, but only when the container runs in detached mode
3Yes, it opens the port on every network interface of the host

Explanation

EXPOSE is metadata for people and tools. docker run -p 8080:3000 (or ports: in Compose) actually maps a host port to the container port.

Further reading

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