How to backup and restore a named docker volume containing MongoDB data

Question

I have a docker image for my mongoDB. I want to make a script that backup production data, and restore it in my local machine, so that I can have a dev environment similar to production.

Here is a part of my docker-compose.yml

 mongo:
    image: "mongo:latest"
    container_name: "espace_client_mongo"
    volumes:
      - mongo-data:/data/db

I want to export data contained in mongo-data volume.

Docs state that I can do it with:

 docker run --rm --volumes-from dbstore -v $(pwd):/backup ubuntu tar cvf /backup/backup.tar /dbdata

but I can't make it work.

When I run it, I get:

ec2-user@espace-client-prod prod]$ docker run --rm --volumes-from espace_client_mongo -v $(pwd):/backup ubuntu tar cvf /backup/backup.tar ./backup
tar: ./backup/backup.tar: file is the archive; not dumped
./backup/
./backup/Caddyfile
./backup/docker-compose.yml
[ec2-user@espace-client-prod prod]$ ls
backup.tar  Caddyfile  docker-compose.yml

It will put the files in current folder into a backup folder. This is not what I want. I want to put the content of docker volume in the backup folder. Am I misunderstanding something ?

EDIT: I would like to backup and restore data with mongo tools ( mongodump and mongorestore)

Answer 1

You can find the data you want to backup in the directory /var/lib/docker/volumes/mongo-data/_data¹ on your host machine. This is what you have at /data/db inside your container.

You don't have to run an additional Docker container just to backup your data if you already have them as a volume. So you only need to run sudo tar cvzf backup.tar.gz /var/lib/docker/volumes/mongo-data/_data from your host machine.

UPDATE

Since you want to use mongodump, just follow the official documentation for the Docker image you're using:

$ docker exec some-mongo sh -c 'exec mongodump -d <database_name> --archive' > /some/path/on/your/host/all-collections.archive

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¹ Note that this volume might have another name, probably prefixed with the folder's name from where you run the docker-compose.yml if you didn't define anything else.