Merge pull request #47346 from luxas/kubeadm_fix_tolerations

Automatic merge from submit-queue

kubeadm: Start using Tolerations in yaml code again and unit-test

**What this PR does / why we need it**:

- Earlier there was a problem with decoding Tolerations from yaml. Seems to be fixed now.
- Added an unit test to catch such a failure if that regression ever happens again

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #

**Special notes for your reviewer**:

Targets v1.8

**Release note**:

```release-note
NONE
```
@kubernetes/sig-cluster-lifecycle-pr-reviews @timothysc

cmd/kubeadm/app/phases/addons/addons.go

@@ -110,7 +110,6 @@ func CreateKubeProxyAddon(configMapBytes, daemonSetbytes []byte, client *clients
 	if err := kuberuntime.DecodeInto(api.Codecs.UniversalDecoder(), daemonSetbytes, kubeproxyDaemonSet); err != nil {
 		return fmt.Errorf("unable to decode kube-proxy daemonset %v", err)
 	}
-	kubeproxyDaemonSet.Spec.Template.Spec.Tolerations = []v1.Toleration{kubeadmconstants.MasterToleration}
 
 	if _, err := client.ExtensionsV1beta1().DaemonSets(metav1.NamespaceSystem).Create(kubeproxyDaemonSet); err != nil {
 		if !apierrors.IsAlreadyExists(err) {
@@ -129,13 +128,6 @@ func CreateKubeDNSAddon(deploymentBytes, serviceBytes []byte, client *clientset.
 	if err := kuberuntime.DecodeInto(api.Codecs.UniversalDecoder(), deploymentBytes, kubednsDeployment); err != nil {
 		return fmt.Errorf("unable to decode kube-dns deployment %v", err)
 	}
-	kubednsDeployment.Spec.Template.Spec.Tolerations = []v1.Toleration{
-		kubeadmconstants.MasterToleration,
-		{
-			Key:      "CriticalAddonsOnly",
-			Operator: "Exists",
-		},
-	}
 
 	if _, err := client.ExtensionsV1beta1().Deployments(metav1.NamespaceSystem).Create(kubednsDeployment); err != nil {
 		if !apierrors.IsAlreadyExists(err) {

cmd/kubeadm/app/phases/addons/manifests.go

@@ -85,10 +85,9 @@ spec:
           readOnly: false
       hostNetwork: true
       serviceAccountName: kube-proxy
-      # TODO: Why doesn't the Decoder recognize this new field and decode it properly? Right now it's ignored
-      # tolerations:
-      # - key: {{ .MasterTaintKey }}
-      #   effect: NoSchedule
+      tolerations:
+      - key: {{ .MasterTaintKey }}
+        effect: NoSchedule
       volumes:
       - name: kube-proxy
         configMap:
@@ -101,7 +100,6 @@ spec:
 	KubeDNSVersion = "1.14.4"
 
 	KubeDNSDeployment = `
-
 apiVersion: extensions/v1beta1
 kind: Deployment
 metadata:
@@ -125,8 +123,6 @@ spec:
     metadata:
       labels:
         k8s-app: kube-dns
-      annotations:
-        scheduler.alpha.kubernetes.io/critical-pod: ''
     spec:
       volumes:
       - name: kube-dns-config
@@ -252,12 +248,11 @@ spec:
             cpu: 10m
       dnsPolicy: Default  # Don't use cluster DNS.
       serviceAccountName: kube-dns
-      # TODO: Why doesn't the Decoder recognize this new field and decode it properly? Right now it's ignored
-      # tolerations:
-      # - key: CriticalAddonsOnly
-      #   operator: Exists
-      # - key: {{ .MasterTaintKey }}
-      #   effect: NoSchedule
+      tolerations:
+      - key: CriticalAddonsOnly
+        operator: Exists
+      - key: {{ .MasterTaintKey }}
+        effect: NoSchedule
       # TODO: Remove this affinity field as soon as we are using manifest lists
       affinity:
         nodeAffinity: