Tutorials:Link to container registry on our server

With the CCU login, you can also access the docker registry on our server. You need this in order to distribute your containers (program code) to the GPU cluster. Think about a registry as a globally available collection of program containers, which can be accessed by everyone in the CCU. You can for example freely pull any container which was created by someone else, make modifications to it, and republish it in your own account. Since a container brings all its dependencies with it, it is guaranteed to run on every system. Thus, you never need to think about for example which drivers or CUDA version is actually installed on a cluster node.

Pushing images to the CCU registry

To check whether your login works and make the CCU registry known to your docker installation, simply run

docker login ccu-k8s.inf.uni-konstanz.de:32250

The registry is exposed on the standard port 32250, and it will ask for your CCU username and password. After this, you will be able to push your own images to the registry.

Example on how to push a specific image

Test the successful connection out now:

docker pull busybox

This will pull the simple example image busybox (a minimalistic Linux) from the default docker registry, the Docker hub, which has tons of useful base images for almost anything you might ever need.

In order to "rebrand" this example and publish it under your own account on the CCU registry, you need to tag it with a new name:

docker tag busybox ccu-k8s.inf.uni-konstanz.de:32250/<your.username>/my_busybox

Note that you are only allowed to upload images in a subdirectory named after your login.

Finally, push the image to the CCU registry:

docker push ccu-k8s.inf.uni-konstanz.de:32250/<your.username>/my_busybox

Pulling images into the GPU cluster

To be able to use your customized image in our GPU cluster, first you have to verify that you have a secret configured to the CCU repository.

After establishing the login with docker, you should have config.json file created in your docker directory, in an Ubuntu installation:

/home/<Your_Ubuntu_Username>/.docker/config.json

In order to create a secret using your login information, type:

kubectl create secret generic <A_Name_For_Your_Secret>  --from-file=.dockerconfigjson=/home/<Your_Ubuntu_Username>/.docker/config.json --type=kubernetes.io/dockerconfigjson

You can check it succeeded by running:

kubectl get secrets
NAME                                 TYPE                             DATA   AGE
<A_Name_For_Your_Secret>             kubernetes.io/dockerconfigjson   1      17d