Ruby-on-rails – Rails server is still running in a new opened docker container

dockerdocker-composedockerfileruby-on-rails

I want to deploy my rails project using Docker. So I use Docker-Compose. But I get one weird error message. When run docker-compose up(this contains db-container with postgresql, redis and web container with rails) I get a

web_1 | => Booting Puma
web_1 | => Rails 4.2.4 application starting in production on http://0.0.0.0:3000
web_1 | => Runrails server -hfor more startup options
web_1 | => Ctrl-C to shutdown server
web_1 | A server is already running. Check /usr/src/app/tmp/pids/server.pid.
web_1 | Exiting

So I cannot understand why do I get this message, because every time I run docker-compose up, new containers start, not the previous. Even if want to delete these server.pid I am not able to do that, because this container isn't running.

my docker-compose.yml file

web:
  dockerfile: Dockerfile-rails
  build: .
  command: bundle exec rails s -p 3000 -b '0.0.0.0'
  ports:
    - "80:3000"
  links:
    - redis
    - db
  environment:
    - REDISTOGO_URL=redis://user@redis:6379/

redis:
  image: redis

db:
  dockerfile: Dockerfile-db
  build: .
  env_file: .env_db

Dockerfile-rails

FROM rails:onbuild

ENV RAILS_ENV=production

I don't think I need to post all my Dockerfiles

UPD: I fixed it by myself: i just deleted all my containers and ran the docker-compose up once again

Best Answer

You are using an onbuild image, so your working direcotry is mounted in the container image. This is very good for developing, since your app is updated in realtime when you edit your code, and your host system gets updated for example when you run a migration.

This also means that your host system tmp directory will be written with the pid file every time a server is running and will remain there if the server is not shut down correctly.

Just run this command from your host system:

sudo rm tmp/pids/server.pid

This can be a real pain when you are for example using foreman under docker-compose, since just pressing ctrl+c will not remove the pid file.

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