I'm relatively new to Docker and I've been using Portainer for managing my containers. I want to transition to using Docker Compose via the command line because it seems simpler for restarting everything from a single configuration file. However, I already have some containers set up in Portainer, and when I copied the stack's configurations to create a new docker-compose.yaml file and tried to run `docker-compose up -d`, I got an error saying that the containers already exist. If I remove them, I risk losing the data stored in the volumes and essentially my service setups. How can I handle this situation? Also, what are good practices for backing up the data stored in these volumes, so I don't lose my service settings?
2 Answers
Swapping to Docker Compose can feel easier for managing your containers after you get the hang of it! With Compose, just ensure you're clear about your data persistence. If you're not using named volumes properly, you'll lose stuff when you delete those containers. It’s there to help you maintain state. Definitely recommend keeping backups; try mapping a directory on your host to your volumes for better data security.
To run your Docker Compose setup, you need to stop the existing containers to free up the names. You can do this with `docker stop `. As long as your data is in named volumes, it should be safe, since volumes persist outside of containers. If you haven't already, make sure to specify the volumes in your docker-compose.yaml to keep that data intact.
Got it! How do I set up those volume mappings in the docker-compose file?