k8s-sizing-webhook

A production ready Kubernetes admission webhook making sure resources are sized correctly using Kubewebhook.

The webhook is based on the production ready Kubewebhook example and comes with:

• Clean and decouple structure.
• Metrics.
• Gracefull shutdown.
• Testing webhooks.
• Serve multiple webhooks on the same application.

Structure

The application is mainly structured in 3 parts:

• main: This is where everything is created, wired, configured and set up, cmd/k8s-sizing-webhook.
• http: This is the package that configures the HTTP server, wires the routes and the webhook handlers. internal/http/webhook.
• Application services: These services have the domain logic of the validators and mutators:
  • mutation/mem: Logic for memfix.bitteeinbit.dev webhook.
  • mutation/cpu: Logic for remove-cpu-limit.bitteeinbit.dev webhook. (TODO)

You can use the example YAML deploy folder to deploy it.

Webhooks

memfix.bitteeinbit.dev

• Webhook type: Mutating.
• Resources affected: deployments, daemonsets, cronjobs, jobs, statefulsets, pods

This webhooks makes the memory guaranteed. This way OOM can be reduced because memory balloning is avoided.

• If both requests and limits are provided, the limit is also used for requests.
• If only requests is set, then limit is set to requests' value.
• If no value is provided, then the resource is left alone.