Fix controlplane running as DaemonSet on single node clusters

This commit fixes passed 'control_plane_replicas' value to Kubernetes
Helm chart which caused kube-scheduler and kube-controller-manager to
run as DaemonSet on single controlplane node clusters, which breaks the
ability to update it gracefully.

It also adds tests that controlplane is using right resource type on
different controlplane sizes and that both can be gracefully updated
without breaking cluster functionality.

Closes #1097
Closes #90

Signed-off-by: Mateusz Gozdek <mateusz@kinvolk.io>

assets/terraform-modules/bootkube/assets.tf

@@ -69,7 +69,7 @@ resource "local_file" "kubernetes" {
     kube_scheduler_image          = var.container_images["kube_scheduler"]
     kube_proxy_image              = var.container_images["kube_proxy"]
     coredns_image                 = "${var.container_images["coredns"]}${var.container_arch}"
-    control_plane_replicas        = max(2, length(var.etcd_servers))
+    control_plane_replicas        = length(var.etcd_servers)
     cloud_provider                = var.cloud_provider
     pod_cidr                      = var.pod_cidr
     service_cidr                  = var.service_cidr

test/components/kubernetes/controlplane-multi-node_test.go

@@ -0,0 +1,73 @@
+// Copyright 2020 The Lokomotive Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build aws aws_edge
+// +build disruptivee2e
+
+package kubernetes_test
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	testutil "github.com/kinvolk/lokomotive/test/components/util"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+func Test_Controlplane_components_are_DaemonSets_on_multi_controller_node_cluster(t *testing.T) {
+	client := testutil.CreateKubeClient(t)
+
+	for c := range components() {
+		c := c
+
+		t.Run(c, func(t *testing.T) {
+			t.Parallel()
+
+			testutil.WaitForDaemonSet(t, client, namespace, c, testutil.RetryInterval, testutil.Timeout)
+		})
+	}
+}
+
+func Test_Controlplane_components_DaemonSets_can_be_gracefully_updated(t *testing.T) {
+	client := testutil.CreateKubeClient(t)
+	deployClient := client.AppsV1().DaemonSets(namespace)
+
+	components := components()
+	components["kube-proxy"] = testutil.RetryInterval
+
+	for c, waitTime := range components {
+		c := c
+		waitTime := waitTime
+
+		t.Run(c, func(t *testing.T) {
+			deploy, err := deployClient.Get(context.TODO(), c, metav1.GetOptions{})
+			if err != nil {
+				t.Fatalf("Getting DaemonSet %q: %v", c, err)
+			}
+
+			// Use current time to have different value on each test run.
+			deploy.Spec.Template.Annotations["update-test"] = time.Now().String()
+
+			if _, err := deployClient.Update(context.TODO(), deploy, metav1.UpdateOptions{}); err != nil {
+				t.Fatalf("Updating DaemonSet %q: %v", c, err)
+			}
+
+			// Wait a bit to let Kubernetes trigger pod updates.
+			time.Sleep(waitTime)
+
+			testutil.WaitForDaemonSet(t, client, namespace, c, testutil.RetryInterval, testutil.Timeout)
+		})
+	}
+}