DPS Docker Network

Since: 2.15.0

DPS can create its own network which is called dps and connect all running containers to that network this way all containers can comunicate to each other, when container A solve container B IP, which will be able to ping B cause they are on the same network (dps). Observes that you are also able to create your own network and make this job of connect the containers you want to be able to talk each other.

Activating by command line

./dns-proxy-server --dps-network-auto-connect

Configuring at json config file

...
"dpsNetworkAutoConnect": true
...

Using environment variable

MG_DPS_NETWORK_AUTO_CONNECT=1 ./dns-proxy-server

OBS: with this feature disabled or not, DPS gives priority to solve bridge networks over the others (if a bridge network were found for the container)

Why it is necessary

We can simulate the issue by the following example:

You have a container running on an overlay network (so you need to be running docker in a swarm mode), then it means the container can not be accessed by the host or by containers which are not in this same network

docker-compose.yml

version: '3.2'
services:
  nginx-1:
    image: nginx
    container_name: nginx-1
    hostname: nginx-1.app
    networks:
      - nginx-network

networks:
  nginx-network:
    driver: overlay
    attachable: true

starting up the container and testing

$ docker-compose up
$ curl --connect-timeout 2 nginx-1.app
curl: (7) Failed to connect to nginx-1.app port 80: Connection timed out

The solution for it can be use dps network or specify a bridge network on the docker-compose.yml

docker-compose.yml

version: '3.2'
services:
  nginx-1:
    image: nginx
    container_name: nginx-1
    hostname: nginx-1.app
    networks:
      - nginx-network
      - nginx-network-bridge

networks:
  nginx-network:
    driver: overlay
    attachable: true
  nginx-network-bridge:
    driver: bridge

$ docker-compose down
$ docker-compose up
$ curl -I --connect-timeout 2 nginx-1.app
HTTP/1.1 200 OK