Hi,
I have follow installation steps from this link https://www.openproject.org/open-source/packaged-installation/packaged-installation-community
After installation, I can access to openproject but my exiting website has gone. So, I need to change URL of the openproject as http://mysite/openproject instead of http://mysite

Thanks

I have the same problem. Did you find a solution?

I tried to change the standard virtual host entry in apache but unfortunately it didn’t work out. Is there a way to change the openproject url to a subdomain via console?

I couldn’t find the solution too.
So, I have changed other site that is using :80 to another port.

Simple and effective. Thank you! :)

Does this answer help?

https://community.openproject.com/topics/6709

Hi Gachoud Philippe

I have tried setting the paramets from a docker image and its not working. any suggestions?

I was able to make this work ( replace /openproject with your base url) 

1. in the configuration.yml file add the line 'rails_relative_url_root: "/openproject"'
2. in the config.ru file, replace the 'map (subdir || '/') do' to 'map '/openproject' do'

build the docker image

If you are running the project with docker-compose, you'll notice there is handling for environment variable OPENPROJECT_RAILS__RELATIVE__URL__ROOT

Set that to whatever you desire in the .env file (or export it) and you should be good to go.
From what I see - a leading / is needed.