Creating a custom image

After you have downloaded the image for the runtime that you want to customize, you can build a new custom image by adding your customizations to the downloaded image. You do this by adding your customizations to a Dockerfile.

You can build a custom image on any server or workstation running Docker, Podman or Skopeo. The custom image does not have to be created on Red Hat Enterprise Linux.

  1. Add your customizations to the Dockerfile. To get started, use the provided Dockerfile sample as a basis on which to create your customized Dockerfile.

    The image is built by reading the instructions from the Dockerfile. The Dockerfile takes as input the base-image-tag argument with the name of base image that you downloaded as its value.

    You should use the example commands that Dockerfile provides to add your customizations to avoid introducing a breaking change, which could prevent the new image from working in Cloud Pak for Data.

    Important:

    • All runtime images in Watson Studio are based on RedHat UBI minimal and use microdnf as the package manager.

    • Do not change the contents in the USER directives as they impact how the container will later run in the cluster:

      • You must be root to install OS packages and to modify the kernel specifications
      • You must be wsbuild to modify the conda environment given by $DSX_KERNEL_CONDENV
    • You should change the display name of the kernel so that you can distinguish between custom images and those provided by Watson Studio.
    • Update the Dockerfile to use the RUN commands that you need. Follow the instructions in the Dockerfile sample for how to update the RUN commands.

  2. Build the new image. The command shows building a new image based on wslocal-x86-runtime-python36:master-273. See Accessing the registry for the value of <your_image_registry_location>.

    • For Docker, enter: 
       docker build -t <new-image-name>:<new-image-tag> --build-arg base_image_tag= <your_image_registry_location>/wslocal-x86-runtime-python36:master-273 -f <path_to_dockerfile> .
    • For Buildah, enter: 
       buildah bud -t <new-image-name>:<new-image-tag> --build-arg base_image_tag= <your_image_registry_location>/wslocal-x86-runtime-python36:master-273 -f <path_to_dockerfile>

      Make sure that you use the correct image and directory setup.