Docker-Compose not able to copy haproxy.cfg

Question

My problem is that I have a docker-compose.yml file and an haproxy.cfg file and I want docker-compose to copy the haproxy.cfg file to the docker container. As per the post Docker composer copy files I can use volumes to do it but in my case I'm getting the below error. Can anybody help me achieve this.

Below is the code and everything

docker-compose.yml

version: "3.3"
services:
 ###After all services are up, we are initializing the gateway
 gateway:
  container_name: gateway-haproxy
  image: haproxy
  volumes:
    - .:/usr/local/etc/haproxy
  ports:
   - 80:80
  network_mode: "host"

Folder Structure

Command output

root@ubuntu:/home/karunesh/Desktop/Stuff/SelfStudy/DevOps/docker# docker-compose up
Creating gateway-haproxy ... 
Creating gateway-haproxy ... done
Attaching to gateway-haproxy
gateway-haproxy | <7>haproxy-systemd-wrapper: executing /usr/local/sbin/haproxy -p /run/haproxy.pid -f /usr/local/etc/haproxy/haproxy.cfg -Ds 
gateway-haproxy | [ALERT] 219/163305 (6) : [/usr/local/sbin/haproxy.main()] No enabled listener found (check for 'bind' directives) ! Exiting.
gateway-haproxy | <5>haproxy-systemd-wrapper: exit, haproxy RC=1
gateway-haproxy exited with code 1

Answer 1

In order to add additional files to the container, you have to build on top of the existing image from haproxy.

For example, your Dockerfile should look like this:

FROM haproxy:latest
COPY haproxy.cfg /usr/local/etc/haproxy/haproxy.cfg

Then you can update your docker compose file accordingly.

If you plan on using this for local development, just mount the file(s), see @MatTheWhale's answer

See more at the official haproxy Docker page

Answer 2

Try this:

volumes:
  - ./haproxy.cfg:/usr/local/etc/haproxy/haproxy.cfg:ro

Instead of mounting the whole directory, this will only mount haproxy.cfg. The ro is an abbreviation for read-only, and its usage guarantees the container won't modify it after it gets mounted.