README

Components

container/

These scripts run inside the Julia/Jupyter container or are used to create it.

• kernel-launchers/

  This directory is expected to be in the container at /usr/local/bin/.

  • julia/scripts/launch_ijuliakernel.jl
    • Started by bootstrap_kernel.sh with the relevant environment variables (kernel ID, public key, etc.) as parameters, which are set by the JEG at container startup. This, in turn, invokes the server_listener.py as a subprocess.
  • julia/scripts/server_listener.py
    • This takes the initial connection parameters from the JEG, attempts to find (but not bind to) available ports accordingly for ZeroMQ, and finally responds to JEG with a so-called connection_file, which includes all parameters to establish a connection between JEG and the Julia kernel.

• bootstrap-kernel.sh

  • The script that is initially invoked when the kernel container starts. Depending on the chosen language, it calls the corresponding runtime. In the case of Julia, launch_ijuliakernel.jl with the necessary parameters from JEG is started.

• eventloop.jl

  • The event loop at the kernel's core that continously receives messages from JEG. This file is slightly extend from recent commits to IJulia and needs to be fixed such that no adaptations are required (see comments and FIXME).

• init.jl

  • The last startup script for IJulia that is invoked by launch_ijuliakernel.jl. This takes the connection parameters created by server_listener.py in order to bind to ZeroMQ ports and set up corresponding message queues. Furthermore, all standard streams are redirected to IJulia.

• Dockerfile

  • The defining file for Julia kernels. It is based on quay.io/jupyter/julia-notebook but extended such that the modified files herein are included in the final image. The startup script is bootstrap-kernel.sh.

gateway/kernelspec-image

These files are meant to be placed at the Jupyter Enterprise Gateway.

• julia_kubernetes/

  • kernel.json
    • This is the kernel specification that defines the image to be used and how Kubernetes is supposed to start the pod that holds the running Julia kernel container.
  • logo-64x64.png
    • The Julia logo.
  • scripts/kernel-pod.yaml.j2
    • The Jinja template that defines the kernel's pod can be modified to mount certain paths or set memory and compute limits, for example.
  • scripts/launch_kubernetes.py
    • With this script, Kubernetes is instructed to initiate a pod according to the kernel specification. This is unaltered, but must be included nonetheless.

• Dockerfile

  • The Dockerfile for this kernelspec image that is mounted by the enterprise gateway pod.

scripts/

• build_kernel_image.sh Builds and pushes the Julia kernel image julia-kernel:alpha

• build_kernelspec_image.sh Builds and pushes the kernel specification image julia-kernelspec:alpha that includes Julia.

• cmd.sh Bash commands to start JEG and JupyterLab in a Minikube cluster.

• pre-pull.sh Some commands that prematurely pull relevant images on the kernel image pullers.

test/

• julia-testnb.ipynb
  • A Julia notebook that allows to test the basic functionalities, including multi-threaded code execution.