Warning: The --link flag is a deprecated legacy feature of Docker. It may eventually be removed. Unless you absolutely need to continue using it, we recommend that you use user-defined networks to facilitate communication between two containers instead of using --link. One feature that user-defined networks do not support that you can do with --link is sharing environmental variables between containers. However, you can use other mechanisms such as volumes to share environment variables between containers in a more controlled way. 出处:https://docs.docker.com/engine/userguide/networking/default_network/dockerlinks/#connect-using-network-port-mapping