noe

Noe: Kubernetes Mutating Webhook for Node Architecture Selection

Blog post announcing and explaining the effort behind Noe

Noe is a Kubernetes mutating webhook that dynamically assigns node architectures to match the requirements of container images within a Pod. It simplifies mixed-architecture deployments (e.g. ARM and x86) by ensuring that Pods are scheduled on nodes capable of executing all their images.

Features

• Automatically adjusts node affinities based on container images' supported architectures
• Improves deployment efficiency by removing the need for manual node selector configuration
• Facilitates seamless mixed-architecture deployments by ensuring compatibility between ARM and x86 nodes

Running Tests

Run all tests using the following command:

go test ./...

Installing Noe

Noe provides a Helm chart, available exclusively from the code repository. The simplest way to install it is to use ArgoCD and define an application such as:

apiVersion: argoproj.io/v1alpha1
kind: Application
spec:
  source:
    repoURL: https://github.com/adevinta/noe.git
    path: charts/noe
    targetRevision: HEAD

Hinting preferred and supported target architectures

By default, Noe will automatically select the appropriate architecture when only one is supported by all the containers in the Pod. If more than one is available, Noe will select the system-defined preferred one if available. This preference can be chosen in the command line for Noe (defaults to amd64 if unspecified):

./noe -preferred-arch amd64

This preference can also be overridden at the Pod level by adding the label:

labels:
  arch.noe.adevinta.com/preferred: amd64

Noe will always prioritize a running Pod, so if the preference is not supported by all the containers in the Pod, the common architecture will be selected.

You can restrict the acceptable common architectures in the command line for Noe:

./noe -cluster-schedulable-archs amd64,arm64

If you specify both a preferred architecture and a list of supported architectures in the command line, the default architecture must be part of the list. Otherwise Noe will fail to start.

If a preferred architecture is specified at the Pod level and is not compatible with the supported architectures listed in the command line, it will be ignored.