docker

Elektra Docker Artifacts

This folder contains all Docker related artifacts.

A list of all Dockerfiles used by the build server can be found in the Jenkinsfile and Jenkinsfile.release.

Note: Any commands in this file are expected to be run from the root of the repository.

Types of Docker images

We generally have three types of docker images:

1. Testing/Packaging Docker images
   These Docker images are used in our test and package stages of our CI and are able to perform tasks like api documentation or DEB/RPM package generation. The prefix of the Dockerfile determines for which task a Dockerfile is used. For example a doc.Dockerfile has all dependencies to generate the api documentation. A dockerfile with the name Dockerfile is used for general full builds and optionally also for package generation. These images do not have any root priviledges.
2. Images that test the Elektra packages (package.Dockerfile)
   Packages are installed during the image build procedure. These images are only used in the Jenkinsfile.release to run test-suites and archive the results. These images do not have any root priviledges.
3. Release images (release.Dockerfile)
   Release images install the latest released version of Elektra (from source or packages) and are pushed to DockerHub and our public Docker registry. During the build stage, tests are executed on the installed version of Elektra. These images are never run as container in our CI as they have permissions to use sudo.

Downloading Released Images

We provide Docker images containing an installed version of Elektra with multiple base images. You can view all available images Docker images on DockerHub. To start for example a Ubuntu Focal based Elektra container with the Elektra version 0.9.5, run docker run -it elektra/elektra:0.9.5-1-focal

Downloading Prebuilt Images

You can download prebuilt images for local testing from our build environment. List available images via docker run --rm anoxis/registry-cli -r https://hub-public.libelektra.org. Afterwards pull your desired image as you would do from any public registry: docker pull hub-public.libelektra.org/build-elektra-alpine:201809-791f9f388cbdff0db544e02277c882ad6e8220fe280cda67e6ea6358767a065e.

Note: We use hub-public instead of hub.libelektra.org which is in use by our build server to bypass authentication. Only GET requests are allowed on hub-public.

Building Images locally

You can build images locally via the following command, if you use bash, sh or zsh:

docker build -t buildelektra-stretch-full \
    --build-arg JENKINS_USERID=`id -u` \
    --build-arg JENKINS_GROUPID=`id -g` \
    -f scripts/docker/debian/stretch/Dockerfile \
    scripts/docker/debian/stretch/

or:

docker build -t buildelektra-stretch-full \
    --build-arg JENKINS_USERID=(id -u) \
    --build-arg JENKINS_GROUPID=(id -g) \
    -f scripts/docker/debian/stretch/Dockerfile \
    scripts/docker/debian/stretch/

, if you use fish.

You can adapt the targeted Dockerfile via -f. You should also adjust the tag used via -t if you are building a different image.

Please note that the complete images used to test Elektra are quite big (~3.7GB) and take a some time (15min+) to build.

Testing Elektra via Docker Images

To replicate errors on the test server you can build the image that ran the test as shown above.

Afterwards you can start the container via the following command:

docker run -it --rm \
    -v "$PWD:/home/jenkins/workspace" \
    -w /home/jenkins/workspace \
    buildelektra-stretch-full

Note since we used matching userid + groupid to your current user the container will write to your mounted directory with the correct permissions.

Once you are running inside the container you can use the same commands as you would use normally to configure/compile and test Elektra. There is also some information on how the build server uses the Docker images as well as the actual instructions executed by the build server in our Jenkinsfiles.

ASAN

If you enable the leak sanitizer using the option ENABLE_ASAN the build might fail printing the following error message:

LeakSanitizer has encountered a fatal error. … HINT: LeakSanitizer does not work under ptrace

. To fix that problem please add the option --cap-add SYS_PTRACE to the docker run command.

Differences to the Build Server

The build server does not create a bash shell inside the containers. Instead it runs a nonterminating command (usually cat) to keep the container open.

Afterwards it executes each step via docker exec.

There might be some more differences that might influence test outcomes. One such documented case is #2008 and #1973 where errors on the test server could not be replicated when running identical commands locally.