Nginx behind Traefik Docker Swarm mode real ip

Question

I'm using Traefik as a reverse proxy in front of nginx service on a docker swarm environment. Here's my docker-stack.yml:

traefik:
    image: traefik
    command: -c /dev/null --web --docker --docker.swarmmode --docker.watch --docker.domain=domain --logLevel=DEBUG
    ports:
      - "8080:8080"
      - "80:80"
      - "443:443"
    networks:
       - app
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    deploy:
      placement:
        constraints: [node.role == manager]

nginx:
    image: nginx
    networks:
      - app
    deploy:
      labels:
        traefik.port: 80
        traefik.docker.network: app
        traefik.frontend.rule: "Host:app.domain"

Everything works fine but I need the real client IP in my Nginx access log, instead I get something like 10.0.1.37

How get I can the real client ip?

Thanks,

Answer 1

This issue was discussed on github #614.

When the upstream service receives requests forwarded from Traefik, the X-Forwarded-For header contains an IP address from the overlay network, not the actual client address.

To overcome this, you can use the new way of declaring service ports in docker-compose >=3.2 (LONG SYNTAX).

Then you ensure that traefik is attached to host network and will send the right X-Forwarded-For header (see below mode: host for the 80 port):

version: "3.2"
services:
  traefik:
    ...
    ports:
      - "8080:8080"
      - target: 80
        published: 80
        protocol: tcp
        mode: host
      - "443:443"
    ...

Finally, you have to change the nginx log_format in the http {} section. That can be done through volume binding of a nginx.conf configuration file:

nginx:
  ..
  volumes:
    - /data/nginx/nginx.conf:/etc/nginx/nginx.conf

you'd have nginx.conf with this:

http {
  ...
  log_format main '$http_x_forwarded_for - $remote_user [$time_local] '
  '"$request" $status $body_bytes_sent "$http_referer" '
  '"$http_user_agent"' ;

Tested on an AWS ec2, the traefik_nginx service (I called my stack traefik) logs like this:

$ docker service logs -f traefik_nginx
...
traefik_nginx.1.qpxyjheql5uk@xxx    | 82.253.xxx.xxx - - [20/Jun/2017:08:46:51 +0000] "GET / HTTP/1.1" 200 612 "-" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.104 Safari/537.36"