### 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")

		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()

  //
  // 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

// 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.

// 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.

  // 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.

  labels:
    {{- toJsonMap
      .InfrastructureLabels
      (strdict
        "gateway.networking.k8s.io/gateway-name" .Name
        "istio.io/gateway-name" .Name
        "gateway.istio.io/managed" "istio.io-mesh-controller"
      ) | nindent 4 }}
  ownerReferences:
  - apiVersion: gateway.networking.k8s.io/v1beta1

	"k8s.io/apimachinery/pkg/types"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/kubernetes/scheme"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/client/fake"
	"sigs.k8s.io/controller-runtime/pkg/client/interceptor"
	"sigs.k8s.io/controller-runtime/pkg/envtest"

	"istio.io/istio/istioctl/pkg/cli"
	"istio.io/istio/operator/pkg/apis/istio/v1alpha1"
	"istio.io/istio/operator/pkg/cache"

  //   Requests for this signer are never auto-approved by kube-controller-manager, can be issued by the "csrsigning" controller in kube-controller-manager.
  //  2. "kubernetes.io/kube-apiserver-client-kubelet": issues client certificates that kubelets use to authenticate to kube-apiserver.

  // where "pod-specific-string" is managed by the StatefulSet controller.
  optional string serviceName = 5;

  // podManagementPolicy controls how pods are created during initial scale up,
  // when replacing pods on nodes, or when scaling down. The default policy is
  // `OrderedReady`, where pods are created in increasing order (pod-0, then
  // pod-1, etc) and the controller will wait until each pod is ready before