调和器使用客户端（pkg/client）访问 API 对象。管理器提供的默认客户端从本地共享缓存（pkg/cache）中读取，并直接写入 API 服务器，但也可以构建只与 API 服务器对话的客户端，而不使用缓存。缓存会自动填充监视对象，并在请求其他结构化对象时自动填充。默认的拆分客户端不承诺在写入过程中使缓存失效（也不承诺按顺序创建/获取一致性），代码不应假定在创建/更新后立即获取会返回更新的资源。缓存还可以有索引，索引可以通过从管理器获取的 FieldIndexer (pkg/client) 创建。索引可用于快速、轻松地查找设置了某些字段的所有对象。调节器可检索事件记录器（pkg/recorder），以便使用管理器发出事件。
// https://github.com/kubernetes-sigs/controller-runtime/blob/v0.17.3/example_test.go#L47
package main
import (
"context"
"fmt"
"os"
appsv1 "k8s.io/api/apps/v1"
corev1 "k8s.io/api/core/v1"
ctrl "sigs.k8s.io/controller-runtime"
"sigs.k8s.io/controller-runtime/pkg/client"
)
// This example creates a simple application Controller that is configured for ReplicaSets and Pods.
//
// * Create a new application for ReplicaSets that manages Pods owned by the ReplicaSet and calls into
// ReplicaSetReconciler.
//
// * Start the application.
func main() {
log := ctrl.Log.WithName("builder-examples")
manager, err := ctrl.NewManager(
ctrl.GetConfigOrDie(),
ctrl.Options{}, // arguments for creating a new Manager, like Scheme, Cache, Client, Election
)
if err != nil {
log.Error(err, "could not create manager")
os.Exit(1)
}
err = ctrl.
NewControllerManagedBy(manager). // Create the Controller
For(&appsv1.ReplicaSet{}). // ReplicaSet is the Application API
Owns(&corev1.Pod{}). // ReplicaSet owns Pods created by it
Complete(&ReplicaSetReconciler{Client: manager.GetClient()})
if err != nil {
log.Error(err, "could not create controller")
os.Exit(1)
}
if err := manager.Start(ctrl.SetupSignalHandler()); err != nil {
log.Error(err, "could not start manager")
os.Exit(1)
}
}
// ReplicaSetReconciler is a simple Controller example implementation.
type ReplicaSetReconciler struct {
client.Client
}
// Implement the business logic:
// This function will be called when there is a change to a ReplicaSet or a Pod with an OwnerReference
// to a ReplicaSet.
//
// * Read the ReplicaSet
// * Read the Pods
// * Set a Label on the ReplicaSet with the Pod count.
func (a *ReplicaSetReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
// Read the ReplicaSet
rs := &appsv1.ReplicaSet{}
err := a.Get(ctx, req.NamespacedName, rs)
if err != nil {
return ctrl.Result{}, err
}
// List the Pods matching the PodTemplate Labels
pods := &corev1.PodList{}
err = a.List(ctx, pods, client.InNamespace(req.Namespace), client.MatchingLabels(rs.Spec.Template.Labels))
if err != nil {
return ctrl.Result{}, err
}
// Update the ReplicaSet
rs.Labels["pod-count"] = fmt.Sprintf("%v", len(pods.Items))
err = a.Update(ctx, rs)
if err != nil {
return ctrl.Result{}, err
}
return ctrl.Result{}, nil
}
// https://github.com/kubernetes-sigs/controller-runtime/blob/v0.17.3/example_test.go#L47
// https://pkg.go.dev/sigs.k8s.io/controller-runtime@v0.17.3/pkg/manager#example-New-LimitToNamespaces
package main
import (
"context"
"fmt"
"os"
appsv1 "k8s.io/api/apps/v1"
corev1 "k8s.io/api/core/v1"
"k8s.io/client-go/rest"
ctrl "sigs.k8s.io/controller-runtime"
"sigs.k8s.io/controller-runtime/pkg/cache"
"sigs.k8s.io/controller-runtime/pkg/client"
)
// This example creates a simple application Controller that is configured for ReplicaSets and Pods.
//
// * Create a new application for ReplicaSets that manages Pods owned by the ReplicaSet and calls into
// ReplicaSetReconciler.
//
// * Start the application.
func main() {
log := ctrl.Log.WithName("builder-examples")
manager, err := ctrl.NewManager(
ctrl.GetConfigOrDie(),
ctrl.Options{
NewCache: func(config *rest.Config, opts cache.Options) (cache.Cache, error) {
opts.DefaultNamespaces = map[string]cache.Config{
"namespace1": {},
"namespace2": {},
}
return cache.New(config, opts)
},
}, // arguments for creating a new Manager, like Scheme, Cache, Client, Election
)
if err != nil {
log.Error(err, "could not create manager")
os.Exit(1)
}
err = ctrl.
NewControllerManagedBy(manager). // Create the Controller
For(&appsv1.ReplicaSet{}). // ReplicaSet is the Application API
Owns(&corev1.Pod{}). // ReplicaSet owns Pods created by it
Complete(&ReplicaSetReconciler{Client: manager.GetClient()})
if err != nil {
log.Error(err, "could not create controller")
os.Exit(1)
}
if err := manager.Start(ctrl.SetupSignalHandler()); err != nil {
log.Error(err, "could not start manager")
os.Exit(1)
}
}
// ReplicaSetReconciler is a simple Controller example implementation.
type ReplicaSetReconciler struct {
client.Client
}
// Implement the business logic:
// This function will be called when there is a change to a ReplicaSet or a Pod with an OwnerReference
// to a ReplicaSet.
//
// * Read the ReplicaSet
// * Read the Pods
// * Set a Label on the ReplicaSet with the Pod count.
func (a *ReplicaSetReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
// Read the ReplicaSet
rs := &appsv1.ReplicaSet{}
err := a.Get(ctx, req.NamespacedName, rs)
if err != nil {
return ctrl.Result{}, err
}
// List the Pods matching the PodTemplate Labels
pods := &corev1.PodList{}
err = a.List(ctx, pods, client.InNamespace(req.Namespace), client.MatchingLabels(rs.Spec.Template.Labels))
if err != nil {
return ctrl.Result{}, err
}
// Update the ReplicaSet
rs.Labels["pod-count"] = fmt.Sprintf("%v", len(pods.Items))
err = a.Update(ctx, rs)
if err != nil {
return ctrl.Result{}, err
}
return ctrl.Result{}, nil
}
// https://github.com/kubernetes-sigs/controller-runtime/blob/v0.17.3/example_test.go#L172
package main
import (
"context"
"fmt"
"os"
"time"
appsv1 "k8s.io/api/apps/v1"
corev1 "k8s.io/api/core/v1"
ctrl "sigs.k8s.io/controller-runtime"
"sigs.k8s.io/controller-runtime/pkg/client"
)
func main() {
log := ctrl.Log.WithName("builder-examples")
leaseDuration := 100 * time.Second
renewDeadline := 80 * time.Second
retryPeriod := 20 * time.Second
manager, err := ctrl.NewManager(
ctrl.GetConfigOrDie(),
ctrl.Options{
LeaseDuration: &leaseDuration,
RenewDeadline: &renewDeadline,
RetryPeriod: &retryPeriod,
})
if err != nil {
log.Error(err, "could not create manager")
os.Exit(1)
}
err = ctrl.
NewControllerManagedBy(manager). // Create the Controller
For(&appsv1.ReplicaSet{}). // ReplicaSet is the Application API
Owns(&corev1.Pod{}). // ReplicaSet owns Pods created by it
Complete(&ReplicaSetReconciler{Client: manager.GetClient()})
if err != nil {
log.Error(err, "could not create controller")
os.Exit(1)
}
if err := manager.Start(ctrl.SetupSignalHandler()); err != nil {
log.Error(err, "could not start manager")
os.Exit(1)
}
}
// ReplicaSetReconciler is a simple Controller example implementation.
type ReplicaSetReconciler struct {
client.Client
}
// Implement the business logic:
// This function will be called when there is a change to a ReplicaSet or a Pod with an OwnerReference
// to a ReplicaSet.
//
// * Read the ReplicaSet
// * Read the Pods
// * Set a Label on the ReplicaSet with the Pod count.
func (a *ReplicaSetReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
// Read the ReplicaSet
rs := &appsv1.ReplicaSet{}
err := a.Get(ctx, req.NamespacedName, rs)
if err != nil {
return ctrl.Result{}, err
}
// List the Pods matching the PodTemplate Labels
pods := &corev1.PodList{}
err = a.List(ctx, pods, client.InNamespace(req.Namespace), client.MatchingLabels(rs.Spec.Template.Labels))
if err != nil {
return ctrl.Result{}, err
}
// Update the ReplicaSet
rs.Labels["pod-count"] = fmt.Sprintf("%v", len(pods.Items))
err = a.Update(ctx, rs)
if err != nil {
return ctrl.Result{}, err
}
return ctrl.Result{}, nil
}
