### Controllers overview

Below provides a high level overview of controllers in Istiod. For more information about each controller, consulting the controllers Go docs is recommended.

```mermaid
graph BT
    crd("CRD Watcher")
    subgraph Service Discovery
        ksd("Kubernetes Controller")
        sesd("Service Entry Controller")

		controllers.WithMaxAttempts(5),
	)
	// We only need to handle pods on our node
	s.pods = kclient.NewFiltered[*corev1.Pod](kubeClient, kclient.Filter{FieldSelector: "spec.nodeName=" + NodeName})
	s.pods.AddEventHandler(controllers.FromEventHandler(func(o controllers.Event) {
		s.queue.Add(o)
	}))

	// Namespaces could be anything though, so we watch all of those
	//

		FieldSelector: strings.Join(fieldSelectors, ","),
	})
	c.queue = controllers.NewQueue("repair pods",
		controllers.WithReconciler(c.Reconcile),
		controllers.WithMaxAttempts(5))
	c.pods.AddEventHandler(controllers.ObjectHandler(c.queue.AddObject))

	return c, nil
}

func (c *Controller) Run(stop <-chan struct{}) {
	kube.WaitForCacheSync("repair controller", stop, c.pods.HasSynced)
	c.queue.Run(stop)
	c.pods.ShutdownHandlers()

// the DaemonSet and StatefulSet controllers for update and rollback, this object is beta. However,
// it may be subject to name and representation changes in future releases, and clients should not
// depend on its stability. It is primarily for internal use by controllers.
message ControllerRevision {
  // Standard object's metadata.

  //
  // More completion modes can be added in the future.
  // If the Job controller observes a mode that it doesn't recognize, which
  // is possible during upgrades due to version skew, the controller
  // skips updates for the Job.
  // +optional
  optional string completionMode = 9;

  // suspend specifies whether the Job controller should create Pods or not. If

  // replicas is the number of Pods created by the StatefulSet controller.
  optional int32 replicas = 2;

  // readyReplicas is the number of pods created by this StatefulSet controller with a Ready Condition.
  optional int32 readyReplicas = 3;

  // currentReplicas is the number of Pods created by the StatefulSet controller from the StatefulSet version
  // indicated by currentRevision.

  // More info: https://kubernetes.io/docs/concepts/workloads/controllers/daemonset/
  optional int32 currentNumberScheduled = 1;

  // The number of nodes that are running the daemon pod, but are
  // not supposed to run the daemon pod.
  // More info: https://kubernetes.io/docs/concepts/workloads/controllers/daemonset/
  optional int32 numberMisscheduled = 2;

	"istio.io/istio/pkg/config/analysis/msg"
	"istio.io/istio/pkg/config/resource"
	"istio.io/istio/pkg/config/schema/gvk"
	"istio.io/istio/pkg/config/schema/kubetypes"
	"istio.io/istio/pkg/kube"
	"istio.io/istio/pkg/kube/controllers"
	"istio.io/istio/pkg/url"
	"istio.io/istio/pkg/util/sets"
)

func Cmd(ctx cli.Context) *cobra.Command {
	var opts clioptions.ControlPlaneOptions
	var skipControlPlane bool

`IstioOperatorSpec` has pass-through fields to the Helm values.yaml API, but these are additionally validated through
a [schema](../operator/pkg/apis/istio/v1alpha1/values_types.proto).
1. [Controller](#k8s-controller) code. The code comprises the K8s listener, webhook and logic for reconciling the cluster
to an `IstioOperatorSpec` CR.
1. [Manifest creation](#manifest-creation) code. User settings are overlaid on top of the

// IngressClassSpec provides information about the class of an Ingress.
message IngressClassSpec {
  // controller refers to the name of the controller that should handle this
  // class. This allows for different "flavors" that are controlled by the
  // same controller. For example, you may have different parameters for the
  // same implementing controller. This should be specified as a
  // domain-prefixed path no more than 250 characters in length, e.g.