# Seeding data volume containers - mongodb

**URL:** <https://forums.docker.com/t/seeding-data-volume-containers-mongodb/2214>\
**Category:** General\
**Created:** [July 3, 2015, 6:35pm UTC](https://forums.docker.com/t/seeding-data-volume-containers-mongodb/2214 "2015-07-03T18:35:10Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![psychemedia](https://sea3.discourse-cdn.com/docker/user_avatar/forums.docker.com/psychemedia/32/1287_2.png) [@psychemedia](https://forums.docker.com/u/psychemedia)\
**Post date:** [July 3, 2015, 6:35pm UTC](https://forums.docker.com/t/seeding-data-volume-containers-mongodb/2214/1 "2015-07-03T18:35:10Z")

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Is there a simple pattern I’m missing for using a docker-compose and Dockerfiles to populate a data volume container within a VM from a dockerfile that orchestrates the import of the data into the database from raw datafiles so that I can then distribute the VM with the seeded data volume container and at a later point fire up a different database container that can mount that data volume?

* * *

_I posted a [related question on SO](http://stackoverflow.com/questions/31210973/how-do-i-seed-a-mongo-database-using-docker-compose) that has a bit more detail around what I tried so far:_

I am trying to distribute a set of connected applications running in several linked containers that includes a mongo database that is required to:

- be distributed containing some seed data;
- allow users to add additional data.

Ideally the data will also be persisted in a linked data volume container.

I can get the data into the `mongo` container using a `mongo` base instance that doesn’t mount any volumes (dockerhub image: `psychemedia/mongo_nomount` - this is essentially the base mongo Dockerfile without the `VOLUME /data/db` statement) and a `Dockerfile` config along the lines of:

```
ADD . /files
WORKDIR /files
RUN mkdir -p /data/db && mongod --fork --logpath=/tmp/mongodb.log && sleep 20 && \
mongoimport --db testdb --collection testcoll --type csv --headerline --file ./testdata.csv #&& mongod --shutdown

```

where `./testdata.csv` is in the same directory (`./mongo-with-data`) as the Dockerfile.

My docker-compose config file includes the following:

```
mongo:
  #image: mongo
  build: ./mongo-with-data
  ports:
    - "27017:27017"
  #Ideally we should be able to mount this against a host directory
  #volumes:
  # - ./db/mongo/:/data/db
  #volumes_from:
  # - devmongodata

#devmongodata:
# command: echo created
# image: busybox
# volumes: 
# - /data/db

```

Whenever I try to mount a VOLUME it seems as if the original seeded data - which is stored in `/data/db` - is deleted. I guess that when a volume is mounted to `/data/db` it replaces whatever is there currently.

That said, the [docker userguide](https://docs.docker.com/userguide/dockervolumes/) suggests that: _Volumes are initialized when a container is created. If the container’s base image contains data at the specified mount point, that existing data is copied into the new volume upon volume initialization_? So I expected the data to persist if I placed the VOLUME command after the seeding `RUN` command?

So what am I doing wrong?

The long view is that I want to automate the build of several linked containers, and then distribute a `Vagrantfile`/docker-compose YAML file that will fire up a set of linked apps, that includes a pre-seeded `mongo` database with a (partially pre-populated) persistent data container.

* * *

What I ultimately want is a recipe for constructing a VM box that contains a seeded data volume container I can mount against a new mongo database container. (It would also be useful to have a way to save backups of the data volume container to host as well as a simple, non-command line recipe to restore those backups.)

The seeded data volume container will contain database files generated by a DBMS (mongo, or perhaps postgresql); the seeded database files themselves need to be constructed from raw data files imported into the DBMS.

What I had in mind was:

- use vagrant/dcoker-compose to fire up DBMS container, import data, saving it to /data/db in a linked data volume container;
- package up the VM box that contains the populated db container
- use a separate docker-compose script to fire up a mongo container and link it to the prepopulated docker volume container.

---

<div class="post-metadata">

**Author:** ![psychemedia](https://sea3.discourse-cdn.com/docker/user_avatar/forums.docker.com/psychemedia/32/1287_2.png) [@psychemedia](https://forums.docker.com/u/psychemedia)\
**Post date:** [July 3, 2015, 8:36pm UTC](https://forums.docker.com/t/seeding-data-volume-containers-mongodb/2214/2 "2015-07-03T20:36:56Z")

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So… to answer my own question:

- simple YAML to create a mongob container and a linked data volume container

- use vagrant docker compose to create the containers

- in Vagrantfile, lines of the form:

to import the data.

Then package the box…

For the distribution, use the box as the basebox, simple YAML file to launch the containers and mount the data volume container…