Generate a PodTemplate for each EDS (#110)

api/v1alpha1/test/new.go

@@ -22,12 +22,13 @@ var apiVersion = fmt.Sprintf("%s/%s", datadoghqv1alpha1.GroupVersion.Group, data
 
 // NewExtendedDaemonSetOptions set of option for the ExtendedDaemonset creation.
 type NewExtendedDaemonSetOptions struct {
-	CreationTime  *time.Time
-	Annotations   map[string]string
-	Labels        map[string]string
-	RollingUpdate *datadoghqv1alpha1.ExtendedDaemonSetSpecStrategyRollingUpdate
-	Canary        *datadoghqv1alpha1.ExtendedDaemonSetSpecStrategyCanary
-	Status        *datadoghqv1alpha1.ExtendedDaemonSetStatus
+	CreationTime    *time.Time
+	Annotations     map[string]string
+	Labels          map[string]string
+	RollingUpdate   *datadoghqv1alpha1.ExtendedDaemonSetSpecStrategyRollingUpdate
+	Canary          *datadoghqv1alpha1.ExtendedDaemonSetSpecStrategyCanary
+	Status          *datadoghqv1alpha1.ExtendedDaemonSetStatus
+	PodTemplateSpec *corev1.PodTemplateSpec
 }
 
 // NewExtendedDaemonSet return new ExtendedDDaemonset instance for test purpose.
@@ -67,6 +68,9 @@ func NewExtendedDaemonSet(ns, name string, options *NewExtendedDaemonSetOptions)
 		if options.Status != nil {
 			dd.Status = *options.Status
 		}
+		if options.PodTemplateSpec != nil {
+			dd.Spec.Template = *options.PodTemplateSpec
+		}
 	}
 
 	return dd

config/rbac/role.yaml

@@ -32,6 +32,18 @@ rules:
   - patch
   - update
   - watch
+- apiGroups:
+  - ""
+  resources:
+  - podtemplates
+  verbs:
+  - create
+  - delete
+  - get
+  - list
+  - patch
+  - update
+  - watch
 - apiGroups:
   - ""
   resources:

controllers/podtemplate/controller.go

@@ -0,0 +1,160 @@
+// Unless explicitly stated otherwise all files in this repository are licensed
+// under the Apache License Version 2.0.
+// This product includes software developed at Datadog (https://www.datadoghq.com/).
+// Copyright 2016-present Datadog, Inc.
+
+package podtemplate
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/go-logr/logr"
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/client-go/tools/record"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
+	"sigs.k8s.io/controller-runtime/pkg/reconcile"
+
+	datadoghqv1alpha1 "github.com/DataDog/extendeddaemonset/api/v1alpha1"
+	"github.com/DataDog/extendeddaemonset/pkg/controller/utils/comparison"
+)
+
+const (
+	// podTemplateDaemonSetLabelKey declares to the cluster-autoscaler that the pod template corresponds to an extra daemonset.
+	podTemplateDaemonSetLabelKey = "cluster-autoscaler.kubernetes.io/daemonset-pod"
+	// podTemplateDaemonSetLabelValueTrue used as podTemplateDaemonSetLabelKey label value.
+	podTemplateDaemonSetLabelValueTrue = "true"
+)
+
+// Reconciler is the internal reconciler for PodTemplate.
+type Reconciler struct {
+	options  ReconcilerOptions
+	client   client.Client
+	scheme   *runtime.Scheme
+	log      logr.Logger
+	recorder record.EventRecorder
+}
+
+// ReconcilerOptions provides options read from command line.
+type ReconcilerOptions struct{}
+
+// NewReconciler returns a reconciler for PodTemplate.
+func NewReconciler(options ReconcilerOptions, client client.Client, scheme *runtime.Scheme, log logr.Logger, recorder record.EventRecorder) (*Reconciler, error) {
+	return &Reconciler{
+		options:  options,
+		client:   client,
+		scheme:   scheme,
+		log:      log,
+		recorder: recorder,
+	}, nil
+}
+
+// Reconcile creates and updates PodTemplate objects corresponding to ExtendedDaemonSets.
+func (r *Reconciler) Reconcile(ctx context.Context, request reconcile.Request) (reconcile.Result, error) {
+	reqLogger := r.log.WithValues("Req.NS", request.Namespace, "Req.Name", request.Name)
+	reqLogger.Info("Reconciling PodTemplate")
+
+	eds := &datadoghqv1alpha1.ExtendedDaemonSet{}
+	err := r.client.Get(context.TODO(), request.NamespacedName, eds)
+	if err != nil {
+		return reconcile.Result{}, err
+	}
+
+	podTpl := &corev1.PodTemplate{}
+	err = r.client.Get(context.TODO(), request.NamespacedName, podTpl)
+	if err != nil {
+		if errors.IsNotFound(err) {
+			return r.createPodTemplate(reqLogger, eds)
+		}
+
+		return reconcile.Result{}, err
+	}
+
+	return r.updatePodTemplateIfNeeded(reqLogger, eds, podTpl)
+}
+
+// createPodTemplate creates a new PodTemplate object corresponding to a given ExtendedDaemonSet.
+func (r *Reconciler) createPodTemplate(logger logr.Logger, eds *datadoghqv1alpha1.ExtendedDaemonSet) (reconcile.Result, error) {
+	podTpl, err := r.newPodTemplate(eds)
+	if err != nil {
+		return reconcile.Result{}, err
+	}
+
+	logger.Info("Creating a new PodTemplate", "podTemplate.Namespace", podTpl.Namespace, "podTemplate.Name", podTpl.Name)
+
+	err = r.client.Create(context.TODO(), podTpl)
+	if err != nil {
+		return reconcile.Result{}, err
+	}
+
+	r.recorder.Event(eds, corev1.EventTypeNormal, "Create PodTemplate", fmt.Sprintf("%s/%s", podTpl.Namespace, podTpl.Name))
+
+	return reconcile.Result{}, nil
+}
+
+// updatePodTemplateIfNeeded updates the PodTemplate object accordingly to the given ExtendedDaemonSet.
+// It does nothing if the PodTemplate is up-to-date.
+func (r *Reconciler) updatePodTemplateIfNeeded(logger logr.Logger, eds *datadoghqv1alpha1.ExtendedDaemonSet, podTpl *corev1.PodTemplate) (reconcile.Result, error) {
+	specHash, err := comparison.GenerateMD5PodTemplateSpec(&eds.Spec.Template)
+	if err != nil {
+		return reconcile.Result{}, fmt.Errorf("cannot generate pod template hash: %w", err)
+	}
+
+	if podTpl.Annotations != nil && podTpl.Annotations[datadoghqv1alpha1.MD5ExtendedDaemonSetAnnotationKey] == specHash {
+		// Already up-to-date
+		return reconcile.Result{}, nil
+	}
+
+	logger.Info("Updating PodTemplate", "podTemplate.Namespace", podTpl.Namespace, "podTemplate.Name", podTpl.Name)
+
+	newPodTpl, err := r.newPodTemplate(eds)
+	if err != nil {
+		return reconcile.Result{}, err
+	}
+
+	err = r.client.Update(context.TODO(), newPodTpl)
+	if err != nil {
+		return reconcile.Result{}, err
+	}
+
+	r.recorder.Event(eds, corev1.EventTypeNormal, "Update PodTemplate", fmt.Sprintf("%s/%s", podTpl.Namespace, podTpl.Name))
+
+	return reconcile.Result{}, nil
+}
+
+// newPodTemplate generates a PodTemplate object based on ExtendedDaemonSet.
+func (r *Reconciler) newPodTemplate(eds *datadoghqv1alpha1.ExtendedDaemonSet) (*corev1.PodTemplate, error) {
+	podTpl := &corev1.PodTemplate{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:        eds.Name,
+			Namespace:   eds.Namespace,
+			Labels:      eds.Labels,
+			Annotations: eds.Annotations,
+		},
+		Template: *eds.Spec.Template.DeepCopy(),
+	}
+
+	specHash, err := comparison.GenerateMD5PodTemplateSpec(&eds.Spec.Template)
+	if err != nil {
+		return nil, fmt.Errorf("cannot generate pod template hash: %w", err)
+	}
+
+	if podTpl.Annotations == nil {
+		podTpl.Annotations = make(map[string]string)
+	}
+
+	podTpl.Annotations[datadoghqv1alpha1.MD5ExtendedDaemonSetAnnotationKey] = specHash
+
+	if podTpl.Labels == nil {
+		podTpl.Labels = make(map[string]string)
+	}
+
+	podTpl.Labels[podTemplateDaemonSetLabelKey] = podTemplateDaemonSetLabelValueTrue
+	err = controllerutil.SetControllerReference(eds, podTpl, r.scheme)
+
+	return podTpl, err
+}