Using custom local domain with Docker - docker

Question

I am running Docker using Docker Desktop on Windows.
I would like to set-up a simple server.
I run it using:
$ docker run -di -p 1234:80 yahya/example-server
This works as expected and runs fine on localhost:1234.
However, I want to give it's own local domain name (e.g. api.example.test), which should only be accessible locally.
Normally for a VM setup I would edit the Windows hosts file, get the IP address of the VM (let's say it's 192.168.90.90) and add something like the following:
192.168.90.90 api.example.test
How would I do something similar in Docker.
I know you can enter an ip address for port forwarding, but if I enter any local IP I get the following error:
$ docker run -di -p 192.168.90.90:1234:80 yahya/example-server
docker: Error response from daemon: Ports are not available: exposing port TCP 192.168.90.90:80 -> 0.0.0.0:0: listen tcp 192.168.90.90:80: can't bind on the specified endpoint.
However, it does work for 10.0.0.7 for some reason (I found this IP automatically added in the hosts file after installing Docker Desktop).
$ docker run -di -p 10.0.0.7:1234:80 yahya/example-server
This essentially solves the issue, but would become an issue again if I have more than 1 project.
Is there a way I can use another local IP address (preferably without a nginx proxy)?

Answer 1

I think there is no simple way to do this without some kind of reverse-proxy.
In my dev environment I use Traefik and dnscrypt-proxy to achieve automatic *.test domain names for multiple projects at same time
First, start Traefik proxy on ports 80 and 433, example docker-compose.yml:
---
networks:
traefik:
name: traefik
services:
traefik:
image: traefik:2.8.3
container_name: traefik
restart: always
volumes:
- /var/run/docker.sock:/var/run/docker.sock
networks:
- traefik
ports:
- 80:80
- 443:443
environment:
TRAEFIK_API: 'true'
TRAEFIK_ENTRYPOINTS_http: 'true'
TRAEFIK_ENTRYPOINTS_http_ADDRESS: :80
TRAEFIK_ENTRYPOINTS_https: 'true'
TRAEFIK_ENTRYPOINTS_https_ADDRESS: :443
TRAEFIK_ENTRYPOINTS_https_HTTP_TLS: 'true'
TRAEFIK_GLOBAL_CHECKNEWVERSION: 'false'
TRAEFIK_GLOBAL_SENDANONYMOUSUSAGE: 'false'
TRAEFIK_PROVIDERS_DOCKER: 'true'
TRAEFIK_PROVIDERS_DOCKER_EXPOSEDBYDEFAULT: 'false'
Then, attach your service to traefik network, and set labels for routing (see Traefik & Docker). Example docker-compose.yml:
---
networks:
traefik:
external: true
services:
example:
image: yahya/example-server
restart: always
labels:
traefik.enable: true
traefik.docker.network: traefik
traefik.http.routers.example.rule: Host(`example.test`)
traefik.http.services.example.loadbalancer.server.port: 80
networks:
- traefik
Finally, add to hosts:
127.0.0.1 example.test
Instead of manually adding all future domains to hosts, you can setup local DNS resolver. I prefer to use cloaking feature of dnscrypt-proxy for this.
You can install it using Installation instructions, then uncomment following line in dnscrypt-proxy.toml:
cloaking_rules = 'cloaking-rules.txt'
and add to cloaking-rules.txt:
*.test 127.0.0.1
finally, setup your network connection to use 127.0.0.1 as DNS resolver