It seems like you are using
docker-compose with a Ruby on Rails application and the
gem:foreman process manager. When you stop the Docker container, the
server.pid file is not being released.
This issue is likely related to how the process manager (Foreman) handles the termination of the Ruby on Rails application inside the Docker container. Foreman may not be able to clean up the
server.pid file properly when the container is stopped abruptly.
To ensure the
server.pid file is released properly and avoid potential conflicts or issues, you can take the following steps:
Use Docker Stop Signal: Ensure that you are using the correct Docker stop signal for your Ruby on Rails application. The stop signal instructs Docker how to terminate the application gracefully when you stop the container.
In your Dockerfile or Docker Compose file, set the
STOPSIGNALinstruction to the appropriate value for Ruby on Rails applications, which is usually
Example in Dockerfile:
Example in Docker Compose:yaml
version: '3' services: web: build: . stop_signal: SIGTERM
Handle Signals in Ruby on Rails: Ensure that your Ruby on Rails application handles the
SIGTERMsignal gracefully. Rails provides a default handler for
SIGTERM, which is to shut down the server gracefully and release the
server.pidfile. However, if you have custom signal handling, ensure it correctly releases resources when the process is terminated.
overmindInstead of Foreman: Consider using an alternative process manager like
overmindinstead of Foreman. Both
overmindare more Docker-friendly and may handle process termination more reliably.
Check File Permissions: Ensure that the directory where the
server.pidfile is stored has the appropriate file permissions so that the process inside the container can create, update, and delete the file.
Use Puma Web Server: If you are using the default WEBrick web server, consider switching to Puma, which is recommended for production use and may handle process termination more gracefully.
By following these steps and ensuring proper signal handling and process management, you can avoid issues with the
server.pid file and ensure your Ruby on Rails application runs smoothly inside the Docker container.