How To Access a Service on Host From a Docker Container

Question

I am new to Docker, I want to run a service running in my host machine from a Docker Container using docker-compose setup file. I tried configuring docker-compose.yml file: 

version: '3' 

services: 

nginx: 

    container_name: cont 

    image: ubuntu 

    command: sleep 10000000 

    networks: 

        - host 

networks: 

    host: 

But was unable to do that. What changes am I supposed to do in the docker-compose.yml file.

Comments

What was the output of this? Any errors?

Answer 1

According to docker-compose documentation you should use network_mode: "host" statement.

Just add the below lines to your docker-compose.yml file:

version: '3' 
services: 
  nginx: 
    container_name: cont 
    image: ubuntu 
    command: sleep 10000000 
    network_mode: "host"

Hope this helps!

Answer 2

To access the service from inside the container you need the port that particular host is listening to as no matter where the service is running we need to access it through the host node. 

Get docker container's hostname

curl 172.17.45.2:8080

If you have a service running on some other port you can access it via 172.17.42.1:5432.

Answer 3

This is one of the way for doing this. Have a fixed set of IPs for both host and the containers. Set up a docker network like this with a common IP address.

docker network create -d bridge --subnet 192.168.0.0/24 --gateway 192.168.0.1 dockernet

Now each container can connect to the host under the fixed IP 192.168.0.1.

You just need to make sure, that you connect all your containers to that “dockernet” network you just created. You can do that with the --net=dockernet option for docker run.

Answer 4

Adding to kalgi's answer, You can also connect to the docker net using your docker-compose file. 

Add the following in your docker-compose file(you'll be connecting to a common IP address network called dockernet).

version: '2'
services:
    db:
        image: some/image
        networks:
            - dockernet
networks:
    dockernet:
        external: true

Comments

Can you please elaborate your explanation and probably give an example with a code snippet.

---

hey DeanWinchester. I hope this gives a better understanding, add the following in your docker-compose file(you'll be connecting to a common IP address network called dockernet).

version: '2'
services:
    db:
        image: some/image
        networks:
            - dockernet
networks:
    dockernet:
        external: true

---

@lina can you post that as an answer or edit your answer with this explanation and code snippet so that's clearer for others having the same doubt.

---

I've updated my answer Kalgi, Hope that's good enough.