You said something about main?

But first, remember how we said we’d come back to main.go again? Let’s take a look and see what’s changed, and what we need to add.

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package main

import (

    kbatchv1 ""
    clientgoscheme ""
    _ ""
    ctrl ""
    batchv1 ""
    // +kubebuilder:scaffold:imports

The first difference to notice is that kubebuilder has added the new API group’s package (batchv1) to our scheme. This means that we can use those objects in our controller.

We’ll also need to add the kubernetes batch v1 (kbatchv1) scheme, since we’re creating and listing Jobs.

var (
    scheme   = runtime.NewScheme()
    setupLog = ctrl.Log.WithName("setup")

func init() {
    _ = clientgoscheme.AddToScheme(scheme)

    _ = kbatchv1.AddToScheme(scheme) // we've added this ourselves
    _ = batchv1.AddToScheme(scheme)
    // +kubebuilder:scaffold:scheme

The other thing that’s changed is that kubebuilder has added a block calling our CronJob controller’s SetupWithManager method. Since we now use a Scheme as well, we’ll need to pass that to the reconciler ourselves.

func main() {

old stuff

    var metricsAddr string
    var enableLeaderElection bool
    flag.StringVar(&metricsAddr, "metrics-addr", ":8080", "The address the metric endpoint binds to.")
    flag.BoolVar(&enableLeaderElection, "enable-leader-election", false,
        "Enable leader election for controller manager. Enabling this will ensure there is only one active controller manager.")


    mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
        Scheme:             scheme,
        MetricsBindAddress: metricsAddr,
        LeaderElection:     enableLeaderElection,
    if err != nil {
        setupLog.Error(err, "unable to start manager")

    if err = (&controllers.CronJobReconciler{
        Client: mgr.GetClient(),
        Log:    ctrl.Log.WithName("controllers").WithName("Captain"),
        Scheme: mgr.GetScheme(), // we've added this ourselves
    }).SetupWithManager(mgr); err != nil {
        setupLog.Error(err, "unable to create controller", "controller", "Captain")
    if err = (&batchv1.CronJob{}).SetupWebhookWithManager(mgr); err != nil {
        setupLog.Error(err, "unable to create webhook", "webhook", "Captain")
    // +kubebuilder:scaffold:builder

old stuff

    setupLog.Info("starting manager")
    if err := mgr.Start(ctrl.SetupSignalHandler()); err != nil {
        setupLog.Error(err, "problem running manager")


Now we can implement our controller.