Introduction

Docker containers wrap up a piece of software in a complete filesystem that contains everything it needs to run: code, runtime, system tools, system libraries – anything you can install on a server. This guarantees that it will always run the same, regardless of the environment it is running in.

www.docker.com/whatisdocker

See the docs for installation instructions (if you are on Windows we highly recommend the Docker Desktop WSL 2 backend).

Images

Docker images can be created by Dockerfiles which can be stacked and thus form a directed graph. OGS-6 image definitions are created with ufz/ogs-container-maker. Built images can be found at the GitLab Container Registry. You can also create images from your local source code.

To build an image by yourself create a Dockerfile:

FROM ubuntu:20.04

RUN ...

Run the build command:

docker build -t repo/image_name path/to/directory

• -t specifies a name for the image, can be arbitrary chosen (but should match the corresponding image on Docker Hub if there is one)
• The path should specify the directory where the Dockerfile is located

Now you can see your build image with $ docker images.

Run a container

To run commands inside a container:

docker run --rm image_name command_to_run

• --rm Cleans up after exiting the container

To run an interactive shell add the -it-switch:

docker run --rm -it image_name

It is useful to mount folders from the host operating system in the Docker container, e.g. to edit source code on your host with your favorite editor:

docker run --rm -it -v /host/directory:/container/directory image_name

Prebuilt OGS-6 Docker images

There are docker images provided on the GitLab Container Registry which include everything necessary to build OGS-6 (e.g. registry.opengeosys.org/ogs/ogs/gcc). They are used by the CI but you can also use them for development. For running the images require CPU capabilities equivalent or better than the Intel Ivybridge¹ architecture.

Even better for development is the usage of Singularity container because they offer a transparent mapping of the user to container space.