Container Canary - Lightning Talk

Q: What is Container Canary?
A: It’s a tool for validating container images

▪ You can define your container requirements as
specification that can be checked into version
control.
▪ Requirements are implemented as Checks that
follow the Kubernetes core.v1.Probes API.
▪ Using the canary CLI you can validate a
container against the specification.
▪ This effectively gives you unit tests for your
containers 🎉

Transcript

1. SciPy 2022 Lightning Talk - Container Canary Jacob Tomlinson
2. Regressions 😔 Recently I made a change to the RAPIDS Docker image so that they could be used on the Kubeflow Notebooks platform. In doing so I broke an NVIDIA service. To avoid making my colleagues sad again in the future I built Container Canary.
3. Q: What is Container Canary? ▪ You can define your container requirements as specification that can be checked into version control. ▪ Requirements are implemented as Checks that follow the Kubernetes core.v1.Probes API. ▪ Using the canary CLI you can validate a container against the specification. ▪ This effectively gives you unit tests for your containers 🎉 A: It’s a tool for validating container images.
4. Q: When is this useful? A: When building container images with the goal of them being used on different platforms. ▪ Many compute platforms support bring-your-own-container, but have some requirements the container must meet. ▪ Images may be expected to run services on specific ports, use a specific UID, use a specific working directory, etc. ▪ These requirements are often documented but not enforced in a technical way. ▪ Container Canary allows you to codify those requirements and test containers ahead of time
5. Example: Binder Binder specifies requirements in it’s documentation for using your own container images in Binder environments. If your container doesn’t fulfil these requirements then the notebook job will fail to start and give you an error. But not necessarily tell you what went wrong. You might have an existing container image that you want to use with Binder, but you’ll need to manually check that you’ve done all the steps in the documentation to ensure it works.
6. Example: Binder With Container Canary we can capture those requirements as a manifest. On the left you can see the example Binder manifest we provide in the GitHub repo. Now you can test your container before you try to use it with Binder and identify exactly which requirement is failing. Below is an example of validating the Docker image I used for my GPU Python tutorial yesterday.
7. How can you help? • Test your containers! • Star the project • Put your manifests on GitHub for others to enjoy
8. Thank you!