Difference between links and depends_on in docker_compose.yml

Question

According to the Docker Compose\'s compose-file documentation:

• depends_on - Express dependency between services.
• links - Lin

Answer 1

The post needs an update after the links option is deprecated.

Basically, links is no longer needed because its main purpose, making container reachable by another by adding environment variable, is included implicitly with network. When containers are placed in the same network, they are reachable by each other using their container name and other alias as host.

For docker run, --link is also deprecated and should be replaced by a custom network.

docker network create mynet
docker run -d --net mynet --name container1 my_image
docker run -it --net mynet --name container1 another_image

depends_on expresses start order (and implicitly image pulling order), which was a good side effect of links.