Gitlab omnibus with docker image - using a relative url gives a 404

Hi there !

I would like to install gitlab omnibus inside a docker container and therefor I used the method described here

The only things that differs from the example is that I need to use a relative url (http://localhost/gitlab instead of http://localhost)
It works when I use http://localhost
It gives a 404 when I use http://localhost/gitlab


  image: 'gitlab/gitlab-ce:latest'
  restart: always
  hostname: 'localhost'
      external_url 'http://localhost/gitlab'
    - '8050:80'
    - '4443:443'
    - '222:22'
    - './config:/etc/gitlab'
    - './logs:/var/log/gitlab'
    - './data:/var/opt/gitlab'

Apache gitlab.conf ’ included to the main apache conf

ProxyPreserveHost On
ProxyPass /gitlab http://localhost:8050/
ProxyPassReverse /gitlab http://localhost:8050/

The only message I see in logs (nginx/gitlab_error.log) that seems relevant to me is

2019/11/20 15:21:23 [error] 531#0: *44 "/var/opt/gitlab/nginx/html/index.html" is not found (2: No such file or directory), client:, server: localhost, request: "GET // HTTP/1.1", host: "localhost"

But this folder does not exist in the 2 use cases… so… I’m quite stuck :wink:

Does anyone have an idea ?