Creating a Data Volume Container in Dockerfile

Create a Docker data volume container in Dockerfile is unbelievably simple, just use the VOLUME instruction:

1
2
FROM debian:8.5
VOLUME ["/data"]

The instruction creates a mount point and attach the volumes from native host or other containers.

Build the data container:

1
2
3
4
5
6
7
8
9
$ docker build -t data .
Sending build context to Docker daemon 2.048 kB
Step 1 : FROM debian:8.5
 ---> 1b088884749b
Step 2 : VOLUME /data
 ---> Running in 5511f34a489c
 ---> 7b723b2b3d13
Removing intermediate container 5511f34a489c
Successfully built 7b723b2b3d13

The built size is just about 125.1 MB.

1
$ docker create --name data data

The first data is the name of the container, the second data is the name of Docker image.

To attach the data volume container to another, we use --volumes-from option:

1
$ docker run -it --rm --name foo --volumes-from=data debian:8.5 /bin/bash

If there’re initial data to copy, then add the COPY instruction:

1
2
3
FROM debian:8.5
VOLUME ["/data"]
COPY . /data

Settings:

1
2
$ docker --version
Docker version 1.11.2, build b9f10c9