Merge pull request #47081 from luxas/kubeadm_postinst_idempotency

Automatic merge from submit-queue (batch tested with PRs 47024, 47050, 47086, 47081, 47013)

kubeadm: Make the creation of the RBAC rules phase idempotent

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

Bugfix: Currently kubeadm fails with a non-zero code if resources it's trying to create already exist. This PR fixes that by making kubeadm try to Update resources that already exist.

After this PR, https://github.com/kubernetes/kubernetes/pull/46879 and a beta.1 release, kubeadm will be fully upgradeable from v1.6 to v1.7 using only kubeadm init.

Last piece of https://github.com/kubernetes/kubeadm/issues/288

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

Fixes: https://github.com/kubernetes/kubeadm/issues/288

**Special notes for your reviewer**:

**Release note**:

```release-note
kubeadm: Modifications to cluster-internal resources installed by kubeadm will be overwritten when upgrading from v1.6 to v1.7.
```
@pipejakob @mikedanese @timothysc

cmd/kubeadm/app/phases/addons/BUILD

@@ -21,6 +21,7 @@ go_library(
         "//cmd/kubeadm/app/images:go_default_library",
         "//cmd/kubeadm/app/util:go_default_library",
         "//pkg/api:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/api/errors:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/runtime:go_default_library",
         "//vendor/k8s.io/client-go/kubernetes:go_default_library",

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

@@ -19,9 +19,9 @@ package addons
 import (
 	"fmt"
 	"net"
-
 	"runtime"
 
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	kuberuntime "k8s.io/apimachinery/pkg/runtime"
 	clientset "k8s.io/client-go/kubernetes"
@@ -80,13 +80,13 @@ func CreateEssentialAddons(cfg *kubeadmapi.MasterConfiguration, client *clientse
 	if err != nil {
 		return err
 	}
-	fmt.Println("[addons] Created essential addon: kube-proxy")
+	fmt.Println("[addons] Applied essential addon: kube-proxy")
 
 	err = CreateKubeDNSAddon(dnsDeploymentBytes, dnsServiceBytes, client)
 	if err != nil {
 		return err
 	}
-	fmt.Println("[addons] Created essential addon: kube-dns")
+	fmt.Println("[addons] Applied essential addon: kube-dns")
 	return nil
 }
 
@@ -97,7 +97,13 @@ func CreateKubeProxyAddon(configMapBytes, daemonSetbytes []byte, client *clients
 	}
 
 	if _, err := client.CoreV1().ConfigMaps(metav1.NamespaceSystem).Create(kubeproxyConfigMap); err != nil {
-		return fmt.Errorf("unable to create a new kube-proxy configmap: %v", err)
+		if !apierrors.IsAlreadyExists(err) {
+			return fmt.Errorf("unable to create a new kube-proxy configmap: %v", err)
+		}
+
+		if _, err := client.CoreV1().ConfigMaps(metav1.NamespaceSystem).Update(kubeproxyConfigMap); err != nil {
+			return fmt.Errorf("unable to update the kube-proxy configmap: %v", err)
+		}
 	}
 
 	kubeproxyDaemonSet := &extensions.DaemonSet{}
@@ -107,7 +113,13 @@ func CreateKubeProxyAddon(configMapBytes, daemonSetbytes []byte, client *clients
 	kubeproxyDaemonSet.Spec.Template.Spec.Tolerations = []v1.Toleration{kubeadmconstants.MasterToleration}
 
 	if _, err := client.ExtensionsV1beta1().DaemonSets(metav1.NamespaceSystem).Create(kubeproxyDaemonSet); err != nil {
-		return fmt.Errorf("unable to create a new kube-proxy daemonset: %v", err)
+		if !apierrors.IsAlreadyExists(err) {
+			return fmt.Errorf("unable to create a new kube-proxy daemonset: %v", err)
+		}
+
+		if _, err := client.ExtensionsV1beta1().DaemonSets(metav1.NamespaceSystem).Update(kubeproxyDaemonSet); err != nil {
+			return fmt.Errorf("unable to update the kube-proxy daemonset: %v", err)
+		}
 	}
 	return nil
 }
@@ -125,9 +137,14 @@ func CreateKubeDNSAddon(deploymentBytes, serviceBytes []byte, client *clientset.
 		},
 	}
 
-	// TODO: All these .Create(foo) calls should instead be more like "kubectl apply -f" commands; they should not fail if there are existing objects with the same name
 	if _, err := client.ExtensionsV1beta1().Deployments(metav1.NamespaceSystem).Create(kubednsDeployment); err != nil {
-		return fmt.Errorf("unable to create a new kube-dns deployment: %v", err)
+		if !apierrors.IsAlreadyExists(err) {
+			return fmt.Errorf("unable to create a new kube-dns deployment: %v", err)
+		}
+
+		if _, err := client.ExtensionsV1beta1().Deployments(metav1.NamespaceSystem).Update(kubednsDeployment); err != nil {
+			return fmt.Errorf("unable to update the kube-dns deployment: %v", err)
+		}
 	}
 
 	kubednsService := &v1.Service{}
@@ -136,7 +153,16 @@ func CreateKubeDNSAddon(deploymentBytes, serviceBytes []byte, client *clientset.
 	}
 
 	if _, err := client.CoreV1().Services(metav1.NamespaceSystem).Create(kubednsService); err != nil {
-		return fmt.Errorf("unable to create a new kube-dns service: %v", err)
+		// Ignore if the Service is invalid with this error message:
+		// 	Service "kube-dns" is invalid: spec.clusterIP: Invalid value: "10.96.0.10": provided IP is already allocated
+
+		if !apierrors.IsAlreadyExists(err) && !apierrors.IsInvalid(err) {
+			return fmt.Errorf("unable to create a new kube-dns service: %v", err)
+		}
+
+		if _, err := client.CoreV1().Services(metav1.NamespaceSystem).Update(kubednsService); err != nil {
+			return fmt.Errorf("unable to create/update the kube-dns service: %v", err)
+		}
 	}
 	return nil
 }

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

@@ -271,6 +271,9 @@ metadata:
     kubernetes.io/name: "KubeDNS"
   name: kube-dns
   namespace: kube-system
+  # Without this resourceVersion value, an update of the Service between versions will yield:
+  #   Service "kube-dns" is invalid: metadata.resourceVersion: Invalid value: "": must be specified for an update
+  resourceVersion: "0"
 spec:
   clusterIP: {{ .DNSIP }}
   ports:

cmd/kubeadm/app/phases/apiconfig/clusterroles.go

@@ -105,8 +105,14 @@ func createRoles(clientset *clientset.Clientset) error {
 		},
 	}
 	for _, role := range roles {
-		if _, err := clientset.RbacV1beta1().Roles(metav1.NamespacePublic).Create(&role); err != nil {
+		if _, err := clientset.RbacV1beta1().Roles(role.ObjectMeta.Namespace).Create(&role); err != nil {
-			return err
+			if !apierrors.IsAlreadyExists(err) {
+				return fmt.Errorf("unable to create RBAC role: %v", err)
+			}
+
+			if _, err := clientset.RbacV1beta1().Roles(role.ObjectMeta.Namespace).Update(&role); err != nil {
+				return fmt.Errorf("unable to update RBAC role: %v", err)
+			}
 		}
 	}
 	return nil
@@ -134,8 +140,14 @@ func createRoleBindings(clientset *clientset.Clientset) error {
 	}
 
 	for _, roleBinding := range roleBindings {
-		if _, err := clientset.RbacV1beta1().RoleBindings(metav1.NamespacePublic).Create(&roleBinding); err != nil {
+		if _, err := clientset.RbacV1beta1().RoleBindings(roleBinding.ObjectMeta.Namespace).Create(&roleBinding); err != nil {
-			return err
+			if !apierrors.IsAlreadyExists(err) {
+				return fmt.Errorf("unable to create RBAC rolebinding: %v", err)
+			}
+
+			if _, err := clientset.RbacV1beta1().RoleBindings(roleBinding.ObjectMeta.Namespace).Update(&roleBinding); err != nil {
+				return fmt.Errorf("unable to update RBAC rolebinding: %v", err)
+			}
 		}
 	}
 	return nil
@@ -155,7 +167,13 @@ func createClusterRoles(clientset *clientset.Clientset) error {
 
 	for _, roleBinding := range clusterRoles {
 		if _, err := clientset.RbacV1beta1().ClusterRoles().Create(&roleBinding); err != nil {
-			return err
+			if !apierrors.IsAlreadyExists(err) {
+				return fmt.Errorf("unable to create RBAC clusterrole: %v", err)
+			}
+
+			if _, err := clientset.RbacV1beta1().ClusterRoles().Update(&roleBinding); err != nil {
+				return fmt.Errorf("unable to update RBAC clusterrole: %v", err)
+			}
 		}
 	}
 	return nil
@@ -216,7 +234,13 @@ func createClusterRoleBindings(clientset *clientset.Clientset) error {
 
 	for _, clusterRoleBinding := range clusterRoleBindings {
 		if _, err := clientset.RbacV1beta1().ClusterRoleBindings().Create(&clusterRoleBinding); err != nil {
-			return err
+			if !apierrors.IsAlreadyExists(err) {
+				return fmt.Errorf("unable to create RBAC clusterrolebinding: %v", err)
+			}
+
+			if _, err := clientset.RbacV1beta1().ClusterRoleBindings().Update(&clusterRoleBinding); err != nil {
+				return fmt.Errorf("unable to update RBAC clusterrolebinding: %v", err)
+			}
 		}
 	}
 	return nil