KCP demo

This demo project is created to reproduce a KCP bug.

I have run this setup for some hours and the measurements kept their trendency.

In this repo

• I used OperatorSDK to scaffold the content of this repo

  • created a single Foo resource with its controller

• downloaded the KCP binary, run locally

What does the controller do

The controller could not be simpler.

The CRD that it works on:

type FooSpec struct {
	Foo string `json:"foo,omitempty"`
}

type FooStatus struct {
	Message string `json:"message,omitempty"`
}

It sets the status message to the foo field's value.

The simplified code:

func (r *FooReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
    var instance demov1alpha1.Foo
    r.Get(ctx, req.NamespacedName, &instance)

    instance.Status.Message = instance.Spec.Foo
    r.Update(ctx, &instance)

    return ctrl.Result{}, nil
}

Run

Prerequsites:

• place a KCP binary under: ./bin/kcp

Hint: tmux helps

• run KCP: make start-kcp

• export KUBECONFIG=$(pwd)/kcp/admin.kubeconfig

• run the operator: make run

• run some stimulus: ./apply-loop.sh

Optional Prometheus

• place a Prometheus binary under: ./bin/prometheus
• run it: make prom
  • process_resident_memory_bytes/1024/1024
  • go_goroutines