Docker in "host" networking mode does not bind ports to the host

Question

On my development machine, I am trying to make a docker container connect to a mysql server on the host. To do this, I have set the networking mode to "host" like so:

phpfpm:
  image: mageinferno/magento2-php:7.0.8-fpm-0
  container_name: php7fpm
  restart: always
  hostname: phpfpm
  ports:
    - "9000:9000"
  environment:
    - APP_MAGE_MODE=developer
  volumes:
    - /Users:/Users
    - /usr/local/var/log/nginx:/var/www/logs
  net: "host"

The problem is that after I start the docker container, I can't telnet to localhost 9000 from the host. Connecting to the container on 9000 is not a problem when the container runs in bridge mode. The docker ps command shows:

CONTAINER ID        IMAGE                                  COMMAND                  CREATED             STATUS              PORTS               NAMES
6de4c973a34a        mageinferno/magento2-php:7.0.8-fpm-0   "/usr/local/bin/start"   4 seconds ago       Up 3 seconds                            php7fpm

Why doesn't the container bind the ports to the host? What am I missing here?

I am on OS X 10.10 using Docker for Mac (Version 1.12.0-rc3-beta18 (build: 9996))

Answer 1

Is there a reason you are trying to use host networking? It can be a bit tricky to set up and is mostly for pretty special use cases. At a minimum, you need to make sure the Docker host allows that port via something like:

iptables -I INPUT 1 -p tcp -m tcp --dport 9000 -j ACCEPT

Otherwise you are probably better sticking with bridge mode.