patch coreDNS deployment for external cloud provider

pkg/installer/installation/coredns.go

@@ -0,0 +1,64 @@
+/*
+Copyright 2019 The KubeOne 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.
+*/
+
+package installation
+
+import (
+	"context"
+
+	"github.com/pkg/errors"
+
+	"github.com/kubermatic/kubeone/pkg/util"
+
+	appsv1 "k8s.io/api/apps/v1"
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+)
+
+func patchCoreDNS(ctx *util.Context) error {
+	if !ctx.Cluster.Provider.External {
+		return nil
+	}
+
+	ctx.Logger.Infoln("Patching coreDNS with uninitialized toleration…")
+
+	if ctx.DynamicClient == nil {
+		return errors.New("kubernetes client not initialized")
+	}
+
+	bgCtx := context.Background()
+	dep := &appsv1.Deployment{}
+	key := client.ObjectKey{
+		Name:      "coredns",
+		Namespace: metav1.NamespaceSystem,
+	}
+
+	err := ctx.DynamicClient.Get(bgCtx, key, dep)
+	if err != nil {
+		return errors.Wrap(err, "failed to get coredns deployment")
+	}
+
+	dep.Spec.Template.Spec.Tolerations = append(dep.Spec.Template.Spec.Tolerations,
+		corev1.Toleration{
+			Key:    "node.cloudprovider.kubernetes.io/uninitialized",
+			Value:  "true",
+			Effect: corev1.TaintEffectNoSchedule,
+		},
+	)
+
+	return errors.Wrap(ctx.DynamicClient.Update(bgCtx, dep), "failed to update coredns deployment")
+}

pkg/installer/installation/install.go

@@ -43,6 +43,7 @@ func Install(ctx *util.Context) error {
 		{Fn: util.BuildKubernetesClientset, ErrMsg: "unable to build kubernetes clientset", Retries: 3},
 		{Fn: features.Activate, ErrMsg: "unable to activate features"},
 		{Fn: applyCanalCNI, ErrMsg: "failed to install cni plugin canal", Retries: 3},
+		{Fn: patchCoreDNS, ErrMsg: "failed to patch CoreDNS", Retries: 3},
 		{Fn: machinecontroller.EnsureMachineController, ErrMsg: "failed to install machine-controller", Retries: 3},
 		{Fn: machinecontroller.WaitReady, ErrMsg: "failed to wait for machine-controller", Retries: 3},
 		{Fn: createWorkerMachines, ErrMsg: "failed to create worker machines", Retries: 3},