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Improve and Simplify the Getting Started Guide
- Refined the sample code implementation to keep it minimal, helping users better understand the core concepts. - Streamlined the guide by focusing on the main information and removing extraneous details. - Ensured that the code and samples in the guide are consistent with the generated project. - Simplified navigation by hiding the full code, making it easier for users to follow along. - Replaced the use of the deploy image plugin with direct commands to provide more comprehensive and straightforward information.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
|
|
@@ -19,28 +19,22 @@ package controller | |
| import ( | ||
| "context" | ||
| "fmt" | ||
| "os" | ||
| "strings" | ||
| "time" | ||
|
|
||
| appsv1 "k8s.io/api/apps/v1" | ||
| corev1 "k8s.io/api/core/v1" | ||
| apierrors "k8s.io/apimachinery/pkg/api/errors" | ||
| "k8s.io/apimachinery/pkg/api/meta" | ||
| metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" | ||
| "k8s.io/apimachinery/pkg/runtime" | ||
| "k8s.io/apimachinery/pkg/types" | ||
| "k8s.io/client-go/tools/record" | ||
| "time" | ||
|
|
||
| "k8s.io/apimachinery/pkg/runtime" | ||
| ctrl "sigs.k8s.io/controller-runtime" | ||
| "sigs.k8s.io/controller-runtime/pkg/client" | ||
| "sigs.k8s.io/controller-runtime/pkg/controller/controllerutil" | ||
| "sigs.k8s.io/controller-runtime/pkg/log" | ||
|
|
||
| cachev1alpha1 "example.com/memcached/api/v1alpha1" | ||
| ) | ||
|
|
||
| const memcachedFinalizer = "cache.example.com/finalizer" | ||
|
|
||
| // Definitions to manage status conditions | ||
| const ( | ||
| // typeAvailableMemcached represents the status of the Deployment reconciliation | ||
|
|
@@ -52,14 +46,9 @@ const ( | |
| // MemcachedReconciler reconciles a Memcached object | ||
| type MemcachedReconciler struct { | ||
| client.Client | ||
| Scheme *runtime.Scheme | ||
| Recorder record.EventRecorder | ||
| Scheme *runtime.Scheme | ||
| } | ||
|
|
||
| // The following markers are used to generate the rules permissions (RBAC) on config/rbac using controller-gen | ||
| // when the command <make manifests> is executed. | ||
| // To know more about markers see: https://book.kubebuilder.io/reference/markers.html | ||
|
|
||
| // +kubebuilder:rbac:groups=cache.example.com,resources=memcacheds,verbs=get;list;watch;create;update;patch;delete | ||
| // +kubebuilder:rbac:groups=cache.example.com,resources=memcacheds/status,verbs=get;update;patch | ||
| // +kubebuilder:rbac:groups=cache.example.com,resources=memcacheds/finalizers,verbs=update | ||
|
|
@@ -77,6 +66,8 @@ type MemcachedReconciler struct { | |
| // For further info: | ||
| // - About Operator Pattern: https://kubernetes.io/docs/concepts/extend-kubernetes/operator/ | ||
| // - About Controllers: https://kubernetes.io/docs/concepts/architecture/controller/ | ||
| // | ||
| // For more details, check Reconcile and its Result here: | ||
| // - https://pkg.go.dev/sigs.k8s.io/[email protected]/pkg/reconcile | ||
| func (r *MemcachedReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) { | ||
| log := log.FromContext(ctx) | ||
|
|
@@ -117,79 +108,6 @@ func (r *MemcachedReconciler) Reconcile(ctx context.Context, req ctrl.Request) ( | |
| } | ||
| } | ||
|
|
||
| // Let's add a finalizer. Then, we can define some operations which should | ||
| // occur before the custom resource is deleted. | ||
| // More info: https://kubernetes.io/docs/concepts/overview/working-with-objects/finalizers | ||
| if !controllerutil.ContainsFinalizer(memcached, memcachedFinalizer) { | ||
| log.Info("Adding Finalizer for Memcached") | ||
| if ok := controllerutil.AddFinalizer(memcached, memcachedFinalizer); !ok { | ||
| log.Error(err, "Failed to add finalizer into the custom resource") | ||
| return ctrl.Result{Requeue: true}, nil | ||
| } | ||
|
|
||
| if err = r.Update(ctx, memcached); err != nil { | ||
| log.Error(err, "Failed to update custom resource to add finalizer") | ||
| return ctrl.Result{}, err | ||
| } | ||
| } | ||
|
|
||
| // Check if the Memcached instance is marked to be deleted, which is | ||
| // indicated by the deletion timestamp being set. | ||
| isMemcachedMarkedToBeDeleted := memcached.GetDeletionTimestamp() != nil | ||
| if isMemcachedMarkedToBeDeleted { | ||
| if controllerutil.ContainsFinalizer(memcached, memcachedFinalizer) { | ||
| log.Info("Performing Finalizer Operations for Memcached before delete CR") | ||
|
|
||
| // Let's add here a status "Downgrade" to reflect that this resource began its process to be terminated. | ||
| meta.SetStatusCondition(&memcached.Status.Conditions, metav1.Condition{Type: typeDegradedMemcached, | ||
| Status: metav1.ConditionUnknown, Reason: "Finalizing", | ||
| Message: fmt.Sprintf("Performing finalizer operations for the custom resource: %s ", memcached.Name)}) | ||
|
|
||
| if err := r.Status().Update(ctx, memcached); err != nil { | ||
| log.Error(err, "Failed to update Memcached status") | ||
| return ctrl.Result{}, err | ||
| } | ||
|
|
||
| // Perform all operations required before removing the finalizer and allow | ||
| // the Kubernetes API to remove the custom resource. | ||
| r.doFinalizerOperationsForMemcached(memcached) | ||
|
|
||
| // TODO(user): If you add operations to the doFinalizerOperationsForMemcached method | ||
| // then you need to ensure that all worked fine before deleting and updating the Downgrade status | ||
| // otherwise, you should requeue here. | ||
|
|
||
| // Re-fetch the memcached Custom Resource before updating the status | ||
| // so that we have the latest state of the resource on the cluster and we will avoid | ||
| // raising the error "the object has been modified, please apply | ||
| // your changes to the latest version and try again" which would re-trigger the reconciliation | ||
| if err := r.Get(ctx, req.NamespacedName, memcached); err != nil { | ||
| log.Error(err, "Failed to re-fetch memcached") | ||
| return ctrl.Result{}, err | ||
| } | ||
|
|
||
| meta.SetStatusCondition(&memcached.Status.Conditions, metav1.Condition{Type: typeDegradedMemcached, | ||
| Status: metav1.ConditionTrue, Reason: "Finalizing", | ||
| Message: fmt.Sprintf("Finalizer operations for custom resource %s name were successfully accomplished", memcached.Name)}) | ||
|
|
||
| if err := r.Status().Update(ctx, memcached); err != nil { | ||
| log.Error(err, "Failed to update Memcached status") | ||
| return ctrl.Result{}, err | ||
| } | ||
|
|
||
| log.Info("Removing Finalizer for Memcached after successfully perform the operations") | ||
| if ok := controllerutil.RemoveFinalizer(memcached, memcachedFinalizer); !ok { | ||
| log.Error(err, "Failed to remove finalizer for Memcached") | ||
| return ctrl.Result{Requeue: true}, nil | ||
| } | ||
|
|
||
| if err := r.Update(ctx, memcached); err != nil { | ||
| log.Error(err, "Failed to remove finalizer for Memcached") | ||
| return ctrl.Result{}, err | ||
| } | ||
| } | ||
| return ctrl.Result{}, nil | ||
| } | ||
|
|
||
| // Check if the deployment already exists, if not create a new one | ||
| found := &appsv1.Deployment{} | ||
| err = r.Get(ctx, types.NamespacedName{Name: memcached.Name, Namespace: memcached.Namespace}, found) | ||
|
|
@@ -282,37 +200,19 @@ func (r *MemcachedReconciler) Reconcile(ctx context.Context, req ctrl.Request) ( | |
| return ctrl.Result{}, nil | ||
| } | ||
|
|
||
| // finalizeMemcached will perform the required operations before delete the CR. | ||
| func (r *MemcachedReconciler) doFinalizerOperationsForMemcached(cr *cachev1alpha1.Memcached) { | ||
| // TODO(user): Add the cleanup steps that the operator | ||
| // needs to do before the CR can be deleted. Examples | ||
| // of finalizers include performing backups and deleting | ||
| // resources that are not owned by this CR, like a PVC. | ||
|
|
||
| // Note: It is not recommended to use finalizers with the purpose of deleting resources which are | ||
| // created and managed in the reconciliation. These ones, such as the Deployment created on this reconcile, | ||
| // are defined as dependent of the custom resource. See that we use the method ctrl.SetControllerReference. | ||
| // to set the ownerRef which means that the Deployment will be deleted by the Kubernetes API. | ||
| // More info: https://kubernetes.io/docs/tasks/administer-cluster/use-cascading-deletion/ | ||
|
|
||
| // The following implementation will raise an event | ||
| r.Recorder.Event(cr, "Warning", "Deleting", | ||
| fmt.Sprintf("Custom Resource %s is being deleted from the namespace %s", | ||
| cr.Name, | ||
| cr.Namespace)) | ||
| // SetupWithManager sets up the controller with the Manager. | ||
| func (r *MemcachedReconciler) SetupWithManager(mgr ctrl.Manager) error { | ||
| return ctrl.NewControllerManagedBy(mgr). | ||
| For(&cachev1alpha1.Memcached{}). | ||
| Owns(&appsv1.Deployment{}). | ||
| Complete(r) | ||
| } | ||
|
|
||
| // deploymentForMemcached returns a Memcached Deployment object | ||
| func (r *MemcachedReconciler) deploymentForMemcached( | ||
| memcached *cachev1alpha1.Memcached) (*appsv1.Deployment, error) { | ||
| ls := labelsForMemcached() | ||
| replicas := memcached.Spec.Size | ||
|
|
||
| // Get the Operand image | ||
| image, err := imageForMemcached() | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
| image := "memcached:1.6.26-alpine3.19" | ||
|
|
||
| dep := &appsv1.Deployment{ | ||
| ObjectMeta: metav1.ObjectMeta{ | ||
|
|
@@ -322,46 +222,15 @@ func (r *MemcachedReconciler) deploymentForMemcached( | |
| Spec: appsv1.DeploymentSpec{ | ||
| Replicas: &replicas, | ||
| Selector: &metav1.LabelSelector{ | ||
| MatchLabels: ls, | ||
| MatchLabels: map[string]string{"app.kubernetes.io/name": "project"}, | ||
| }, | ||
| Template: corev1.PodTemplateSpec{ | ||
| ObjectMeta: metav1.ObjectMeta{ | ||
| Labels: ls, | ||
| Labels: map[string]string{"app.kubernetes.io/name": "project"}, | ||
| }, | ||
| Spec: corev1.PodSpec{ | ||
| // TODO(user): Uncomment the following code to configure the nodeAffinity expression | ||
| // according to the platforms which are supported by your solution. It is considered | ||
| // best practice to support multiple architectures. build your manager image using the | ||
| // makefile target docker-buildx. Also, you can use docker manifest inspect <image> | ||
| // to check what are the platforms supported. | ||
| // More info: https://kubernetes.io/docs/concepts/scheduling-eviction/assign-pod-node/#node-affinity | ||
| // Affinity: &corev1.Affinity{ | ||
| // NodeAffinity: &corev1.NodeAffinity{ | ||
| // RequiredDuringSchedulingIgnoredDuringExecution: &corev1.NodeSelector{ | ||
| // NodeSelectorTerms: []corev1.NodeSelectorTerm{ | ||
| // { | ||
| // MatchExpressions: []corev1.NodeSelectorRequirement{ | ||
| // { | ||
| // Key: "kubernetes.io/arch", | ||
| // Operator: "In", | ||
| // Values: []string{"amd64", "arm64", "ppc64le", "s390x"}, | ||
| // }, | ||
| // { | ||
| // Key: "kubernetes.io/os", | ||
| // Operator: "In", | ||
| // Values: []string{"linux"}, | ||
| // }, | ||
| // }, | ||
| // }, | ||
| // }, | ||
| // }, | ||
| // }, | ||
| // }, | ||
| SecurityContext: &corev1.PodSecurityContext{ | ||
| RunAsNonRoot: &[]bool{true}[0], | ||
| // IMPORTANT: seccomProfile was introduced with Kubernetes 1.19 | ||
| // If you are looking for to produce solutions to be supported | ||
| // on lower versions you must remove this option. | ||
| SeccompProfile: &corev1.SeccompProfile{ | ||
| Type: corev1.SeccompProfileTypeRuntimeDefault, | ||
| }, | ||
|
|
@@ -383,7 +252,7 @@ func (r *MemcachedReconciler) deploymentForMemcached( | |
| }, | ||
| }, | ||
| Ports: []corev1.ContainerPort{{ | ||
| ContainerPort: memcached.Spec.ContainerPort, | ||
| ContainerPort: 11211, | ||
| Name: "memcached", | ||
| }}, | ||
| Command: []string{"memcached", "-m=64", "-o", "modern", "-v"}, | ||
|
|
@@ -400,49 +269,3 @@ func (r *MemcachedReconciler) deploymentForMemcached( | |
| } | ||
| return dep, nil | ||
| } | ||
|
|
||
| // labelsForMemcached returns the labels for selecting the resources | ||
| // More info: https://kubernetes.io/docs/concepts/overview/working-with-objects/common-labels/ | ||
| func labelsForMemcached() map[string]string { | ||
| var imageTag string | ||
| image, err := imageForMemcached() | ||
| if err == nil { | ||
| imageTag = strings.Split(image, ":")[1] | ||
| } | ||
| return map[string]string{"app.kubernetes.io/name": "project", | ||
| "app.kubernetes.io/version": imageTag, | ||
| "app.kubernetes.io/managed-by": "MemcachedController", | ||
| } | ||
| } | ||
|
|
||
| // imageForMemcached gets the Operand image which is managed by this controller | ||
| // from the MEMCACHED_IMAGE environment variable defined in the config/manager/manager.yaml | ||
| func imageForMemcached() (string, error) { | ||
| var imageEnvVar = "MEMCACHED_IMAGE" | ||
| image, found := os.LookupEnv(imageEnvVar) | ||
| if !found { | ||
| return "", fmt.Errorf("Unable to find %s environment variable with the image", imageEnvVar) | ||
| } | ||
| return image, nil | ||
| } | ||
|
|
||
| // SetupWithManager sets up the controller with the Manager. | ||
| // The whole idea is to be watching the resources that matter for the controller. | ||
| // When a resource that the controller is interested in changes, the Watch triggers | ||
| // the controller’s reconciliation loop, ensuring that the actual state of the resource | ||
| // matches the desired state as defined in the controller’s logic. | ||
| // | ||
| // Notice how we configured the Manager to monitor events such as the creation, update, | ||
| // or deletion of a Custom Resource (CR) of the Memcached kind, as well as any changes | ||
| // to the Deployment that the controller manages and owns. | ||
| func (r *MemcachedReconciler) SetupWithManager(mgr ctrl.Manager) error { | ||
| return ctrl.NewControllerManagedBy(mgr). | ||
| // Watch the Memcached CR(s) and trigger reconciliation whenever it | ||
| // is created, updated, or deleted | ||
| For(&cachev1alpha1.Memcached{}). | ||
| // Watch the Deployment managed by the MemcachedReconciler. If any changes occur to the Deployment | ||
| // owned and managed by this controller, it will trigger reconciliation, ensuring that the cluster | ||
| // state aligns with the desired state. See that the ownerRef was set when the Deployment was created. | ||
| Owns(&appsv1.Deployment{}). | ||
| Complete(r) | ||
| } | ||
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