Docker

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.

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 Docker Hub. You can also create images from your local source code.

To build an image by yourself create a Dockerfile:

FROM ubuntu:17.10

RUN ...

Run the build command:

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

• --rm Cleans up after exiting the container
• -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 -t image_name command_to_run

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

$ docker run --rm -i -t 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 -i -t -v /host/directory:/container/directory image_name

Prebuilt OGS-6 Docker images

There are docker images provided on Docker Hub which include everything necessary to build OGS-6. They are intended to be used by Jenkins. Do not use them for development as you will run into permission issues (when mounting your source code into the container: in the container you are the jenkins user which has other uid and gid).

Use Singularity container for development instead.

There are images for gcc and clang.

OGS-6 images used by Jenkins

The following images are used by Jenkins:

• ogs6/gcc, defined in scripts/docker/Dockerfile.gcc.full
• ogs6/gcc:gui, defined in scripts/docker/Dockerfile.gcc.gui
• ogs6/clang, defined in scripts/docker/Dockerfile.clang.full