Traefik with docker backend leads to bad gateway - docker

Question

I set up a debian server where I installed docker and docker-compose.
I created in the home of my sudo user a folder with the following hierarchy:
~/docker-project
- docker-compose.yml
- /traefik/traefik.toml
I do a docker-compose up -d everything is started I can reach traefik.mydomain.com that has working ssl certificate as does the other subdomains. But if I go to any of my subdomain to reach my dockerized web service, I get a bad gateway message in my browser. If I go to my server IP adress and put the right port, I see my webservice working perfectly.
So I think I've made a mistake configuring the docker / traefik relationship but I'm unable to find where.
Here is my traefik.toml:
defaultEntryPoints = ["http", "https"]
################################################################
# Web configuration backend
################################################################
[web]
address = ":8080"
[web.auth.basic]
# User: user | Password: password
users = ["user:hashedpassword"]
################################################################
# Entry-points configuration
################################################################
[entryPoints]
[entryPoints.http]
address = ":80"
[entryPoints.http.redirect]
entryPoint = "https"
[entryPoints.https]
address = ":443"
[entryPoints.https.tls]
################################################################
# Docker configuration backend
################################################################
[docker]
domain = "mydomain.com"
watch = true
exposedbydefault = false
################################################################
# Let's encrypt
################################################################
[acme]
email = "my-email#mail.com"
storageFile = "/etc/traefik/acme.json"
onDemand = false
onHostRule = true
entryPoint = "https"
Here is my docker-compose.yml:
version: '2'
services:
traefik:
restart: always
image: traefik
container_name: traefik
ports:
- '80:80'
- '443:443'
- '8080:8080'
labels:
- 'traefik.enable=true'
- 'traefik.docker.network=dockerplatform_default'
- 'traefik.port=8080'
- 'traefik.frontend.rule=Host:traefik.mydomain.com'
volumes:
- /var/run/docker.sock:/var/run/docker.sock
- ./traefik:/etc/traefik
plex:
image: linuxserver/plex
container_name: plex
environment:
- VERSION=latest
- PUID=1000
- PGID=1000
- TZ=TZ
labels:
- 'traefik.enable=true'
- 'traefik.docker.network=dockerplatform_default'
- 'traefik.port=9001'
- 'traefik.frontend.rule=Host:plex.mydomain.com'
ports:
- '9001:32400'
volumes:
- 'plex:/config'
- 'plex_transcode:/transcode'
- '/home/downloader/Downloads:/data/'
plexpy:
image: linuxserver/plexpy
container_name: plexpy
environment:
- PUID=1000
- PGID=1000
- TZ=TZ
labels:
- 'traefik.enable=true'
- 'traefik.docker.network=dockerplatform_default'
- 'traefik.port=9002'
- 'traefik.frontend.rule=Host:plexpy.mydomain.com'
ports:
- '9002:8181'
volumes:
- 'plexpy:/config'
transmission:
image: linuxserver/transmission
container_name: transmission
environment:
- PGID=1000
- PUID=1000
- TZ=TZ
labels:
- 'traefik.enable=true'
- 'traefik.docker.network=dockerplatform_default'
- 'traefik.port=9003'
- 'traefik.frontend.rule=Host:bt.mydomain.com'
ports:
- '9003:9091'
- '51413:51413'
- '51413:51413/udp'
volumes:
- 'transmission:/config'
- '/home/downloader/Downloads:/downloads'
- '/home/downloader/Downloads:/watch'
volumes:
plex:
driver: local
plex_transcode:
driver: local
plexpy:
driver: local
transmission:
driver: local
Thank you for your help.

Answer 1

So I managed to get an answer thanks to the terrific traefik slack channel!
So my containers are all in the same docker network including my traefik container.
The problem is that I mapped all my containers port to be accessible from the host machine.
Instead I should have only mapped traefik ports to the host machine and just exposed the ports of my web services containers so that traefik can listen to them inside the docker network where they are all in.
Change : - add expose
- change traefik.port
I just had to do this changes in my docker-compose.yml:
version: '2'
services:
traefik:
restart: always
image: traefik
container_name: traefik
ports:
- '80:80'
- '443:443'
- '8080:8080'
labels:
- 'traefik.enable=true'
- 'traefik.docker.network=dockerplatform_default'
- 'traefik.port=8080'
- 'traefik.frontend.rule=Host:traefik.mydomain.com'
volumes:
- /var/run/docker.sock:/var/run/docker.sock
- ./traefik:/etc/traefik
plex:
image: linuxserver/plex
container_name: plex
environment:
- VERSION=latest
- PUID=1000
- PGID=1000
- TZ=TZ
labels:
- 'traefik.enable=true'
- 'traefik.docker.network=dockerplatform_default'
- 'traefik.port=32400'
- 'traefik.frontend.rule=Host:plex.mydomain.com'
#ports:
# - '9001:32400'
expose:
- 32400
volumes:
- 'plex:/config'
- 'plex_transcode:/transcode'
- '/home/downloader/Downloads:/data/'
plexpy:
image: linuxserver/plexpy
container_name: plexpy
environment:
- PUID=1000
- PGID=1000
- TZ=TZ
labels:
- 'traefik.enable=true'
- 'traefik.docker.network=dockerplatform_default'
- 'traefik.port=8181'
- 'traefik.frontend.rule=Host:plexpy.mydomain.com'
#ports:
# - '9002:8181'
expose:
- 8181
volumes:
- 'plexpy:/config'
transmission:
image: linuxserver/transmission
container_name: transmission
environment:
- PGID=1000
- PUID=1000
- TZ=TZ
labels:
- 'traefik.enable=true'
- 'traefik.docker.network=dockerplatform_default'
- 'traefik.port=9091'
- 'traefik.frontend.rule=Host:bt.mydomain.com'
#ports:
# - '9003:9091'
# - '51413:51413'
# - '51413:51413/udp'
expose:
- 9091
- 51413
volumes:
- 'transmission:/config'
- '/home/downloader/Downloads:/downloads'
- '/home/downloader/Downloads:/watch'
volumes:
plex:
driver: local
plex_transcode:
driver: local
plexpy:
driver: local
transmission:
driver: local

Answer 2

As Traefik v2 is out now, this question deserves an update:
The expose port defnition isn't necessary anymore.
Neither is a port mapping definition for that container.
The only thing necessary is, that something in the container is listening.
Note: If you define for e.g. an Nginx container, add the label
- 'traefik.port=9091'
but also add a server conf that listens on port 9091.