How to deal with persistent storage e g databases in docker

Question

I am currently using this approach: build the image, e.g. for Postgres, and then start the container with

docker run --volumes-from c0dbc34fd631 -d app_name/postgres

IMHO, that has the drawback, that I must not ever (by accident) delete container "c0dbc34fd631".

Another idea would be to mount host volumes "-v" into the container, however, the userid within the container does not necessarily match the userid from the host, and then permissions might be messed up.

How deal with persistent storage for your docker containers?

Answer 1

For Docker 1.9.0 and above,

Use volume API

docker volume create --name hello

docker run -d -v hello:/container/path/for/volume container_image my_command

If you create a container with a -v volume_name:/container/fs/pathdocker will automatically create a named volume for you that can:

1. Be listed through the docker volume ls
2. Be identified through the docker volume inspect volume_name
3. Backed up as a normal dir
4. Backed up as before through a --volumes-from connection

The new volume api adds a useful command that let you identify dangling volumes:

docker volume ls -f dangling=true

And then remove it through its name:

docker volume rm <volume name>

as @mpugach underlines in the comments you can get rid of all the dangling volumes with a nice one liner:

docker volume rm $(docker volume ls -f dangling=true -q)

# or using 1.13.x

docker volume prune

Hope this answer helps you.