Skip to main content

Docker Basics

Example - build and run local docker image from dockerfile​

Start with a dockerfile. The name can (should?) be dockerfile with no extension. Here's an example.

FROM mcr.microsoft.com/azureml/base

ARG AZURE_SDK_VERSION=1.7.0
ARG SKLEARN_VERSION=0.23.1

RUN pip install --upgrade pip
RUN pip install azureml-core==${AZURE_SDK_VERSION} azureml-sdk==${AZURE_SDK_VERSION}
RUN pip install scikit-learn==${SKLEARN_VERSION}

(Assuming you have docker installed and are in a shell where you can run docker commands. Test by running docker images for example.)

Navigate to the directory housing your dockerfile and run the following:

docker build --tag aml:1.0 .

NB. Take note of the . at the end of the command. We are specifying the current working directory.

NB. The --tag here of the form <name>:<version> of the image.

If you run docker images you should now see your image as tagged.

REPOSITORY  TAG     IMAGE ID        CREATED         SIZE
aml         1.0     38540699060f    4 minutes ago   1.68GB
...

To run this image as a container:

docker run --name test -it aml:1.0

NB.

  • The --name flag will assign a name (in this case test) to the container
  • The -i flag (alternatively --interactive) will "Keep STDIN open even if not attached"
  • The -t flag will "Allocate a pseudo-TTY"

The above command will land you in an interactive shell in a container built from the aml:1.0 image. To exit the container run exit, which will return you.

See running containers​

The docker ps command (docs) allows you to see containers.

docker ps

Adding the -a flag will show all container, both stopped and running.

Copy files from host to running container​

From this stack overflow question.

docker cp foo.txt mycontainer:/foo.txt

where mycontainer is a container ID, not an image ID.

To copy files from the container:

docker cp mycontainer:/foo.txt foo.txt

To copy multiple files to/from the container:

docker cp src/. mycontainer:/target
docker cp mycontainer:/src/. target