Docker access host IP by resolving specific domain name

docker-access-host.md

Solution:

1. Docker desktop (tested on Macos): use special DNS name host.docker.internal
2. Linux:

• use --network host on docker run, and use localhost. This has same network namespace (better performance but less security)
• or --add-host=host.docker.internal:host-gateway, so that the containers using NAT can resolve host IP by domain name of host.docker.internal

Use case: docker compose file:

version: 'x.x'

services:

  xxx:
    build:
      context: .
    extra_hosts:
      - "host.docker.internal:host-gateway"

Ref:

• https://docs.docker.com/desktop/networking/#i-want-to-connect-from-a-container-to-a-service-on-the-host
• https://stackoverflow.com/questions/48546124/what-is-linux-equivalent-of-host-docker-internal