Does stopping docker-compose containers unmount volumes?

问题

As part of my quest to completely understand how docker deals with volumes under the hood (followup from my previous post), I'm curious about how running docker-compose stop deals with volumes.

There are two possibilities that I suppose may happen:

1. Volumes are unmounted after running docker-compose stop and then mounted again in lexographic order when running docker-compose start.
2. Volumes stay mounted until the container is removed using docker-compose rm or a similar command.

I was curious as even restarting a stopped container will create an empty directory in my host folder. I have the following in my docker-compose.yml:

volumes:
- .:/var/www/app
- my_modules:/var/www/app/node_modules

So, from my understanding of the answer in the linked post above, the empty directory is created because of the following:

1. Bind mount happens first (lexographic order), overwrites everything in /var/www/app
2. Docker will try to mount node_modules, but since the directory no longer exists in the container (overwritten), it will mkdir node_modules to have a directory to mount the named volume.
3. Since the bind mount already exists when the mkdir happens, I see a new, empty node_modules folder in my host.

This makes complete sense if the volumes are being mounted, but if 2) is true and they stay mounted even after running docker-compose stop, why would I still be seeing an empty directory being created in my host? I remove node-modules from my host in between the stop and up command for reproducing this behavior.

来源：https://stackoverflow.com/questions/56317302/does-stopping-docker-compose-containers-unmount-volumes