operator-sdk-memcached-operator-implement-controller-2-create-deployment.go

...

import (
    appsv1 "k8s.io/api/apps/v1" // added
    corev1 "k8s.io/api/core/v1" // added
    "k8s.io/apimachinery/pkg/api/errors"
    metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" // added
    "k8s.io/apimachinery/pkg/types" // added

    "context"

        ...
)

...

//+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
//+kubebuilder:rbac:groups=apps,resources=deployments,verbs=get;list;watch;create;update;patch;delete // added
//+kubebuilder:rbac:groups=core,resources=pods,verbs=get;list; // added

...

func (r *MemcachedReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
    log := r.Log.WithValues("memcached", req.NamespacedName)

    // 1. Fetch the Memcached instance
        // ...already implemented in the previous section

    // 2. 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)
    if err != nil && errors.IsNotFound(err) {
        // Define a new deployment
        dep := r.deploymentForMemcached(memcached)
        log.Info("2. Check if the deployment already exists, if not create a new one. Creating a new Deployment", "Deployment.Namespace", dep.Namespace, "Deployment.Name", dep.Name)
        err = r.Create(ctx, dep)
        if err != nil {
            log.Error(err, "2. Check if the deployment already exists, if not create a new one. Failed to create new Deployment", "Deployment.Namespace", dep.Namespace, "Deployment.Name", dep.Name)
            return ctrl.Result{}, err
        }
        // Deployment created successfully - return and requeue
        return ctrl.Result{Requeue: true}, nil
    } else if err != nil {
        log.Error(err, "2. Check if the deployment already exists, if not create a new one. Failed to get Deployment")
        return ctrl.Result{}, err
    }

    return ctrl.Result{}, nil
}

// deploymentForMemcached returns a memcached Deployment object
func (r *MemcachedReconciler) deploymentForMemcached(m *cachev1alpha1.Memcached) *appsv1.Deployment {
    ls := labelsForMemcached(m.Name)
    replicas := m.Spec.Size

    dep := &appsv1.Deployment{
        ObjectMeta: metav1.ObjectMeta{
            Name:      m.Name,
            Namespace: m.Namespace,
        },
        Spec: appsv1.DeploymentSpec{
            Replicas: &replicas,
            Selector: &metav1.LabelSelector{
                MatchLabels: ls,
            },
            Template: corev1.PodTemplateSpec{
                ObjectMeta: metav1.ObjectMeta{
                    Labels: ls,
                },
                Spec: corev1.PodSpec{
                    Containers: []corev1.Container{{
                        Image:   "memcached:1.4.36-alpine",
                        Name:    "memcached",
                        Command: []string{"memcached", "-m=64", "-o", "modern", "-v"},
                        Ports: []corev1.ContainerPort{{
                            ContainerPort: 11211,
                            Name:          "memcached",
                        }},
                    }},
                },
            },
        },
    }
    // Set Memcached instance as the owner and controller
    ctrl.SetControllerReference(m, dep, r.Scheme)
    return dep
}

// labelsForMemcached returns the labels for selecting the resources
// belonging to the given memcached CR name.
func labelsForMemcached(name string) map[string]string {
    return map[string]string{"app": "memcached", "memcached_cr": name}
}

...