Merge pull request #78033 from rajansandeep/corednsmigration

Add the ability to migrate CoreDNS configmap in kubeadm

cmd/kubeadm/app/phases/upgrade/BUILD

@@ -7,6 +7,7 @@ go_library(
         "health.go",
         "policy.go",
         "postupgrade.go",
+        "preflight.go",
         "prepull.go",
         "staticpods.go",
         "versiongetter.go",
@@ -44,7 +45,9 @@ go_library(
         "//staging/src/k8s.io/apimachinery/pkg/util/sets:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/version:go_default_library",
         "//staging/src/k8s.io/client-go/kubernetes:go_default_library",
+        "//vendor/github.com/coredns/corefile-migration/migration:go_default_library",
         "//vendor/github.com/pkg/errors:go_default_library",
+        "//vendor/k8s.io/klog:go_default_library",
         "//vendor/k8s.io/utils/pointer:go_default_library",
     ],
 )

cmd/kubeadm/app/phases/upgrade/preflight.go

@@ -0,0 +1,114 @@
+/*
+Copyright 2019 The Kubernetes 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 upgrade
+
+import (
+	"os"
+
+	"github.com/coredns/corefile-migration/migration"
+	"github.com/pkg/errors"
+
+	"k8s.io/apimachinery/pkg/util/sets"
+	clientset "k8s.io/client-go/kubernetes"
+	"k8s.io/klog"
+	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
+	kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
+	"k8s.io/kubernetes/cmd/kubeadm/app/phases/addons/dns"
+	"k8s.io/kubernetes/cmd/kubeadm/app/preflight"
+)
+
+// CoreDNSCheck validates installed kubelet version
+type CoreDNSCheck struct {
+	name   string
+	client clientset.Interface
+	f      func(clientset.Interface) error
+}
+
+// Name is part of the preflight.Checker interface
+func (c CoreDNSCheck) Name() string {
+	return c.name
+}
+
+// Check is part of the preflight.Checker interface
+func (c CoreDNSCheck) Check() (warnings, errors []error) {
+	if err := c.f(c.client); err != nil {
+		return nil, []error{err}
+	}
+	return nil, nil
+}
+
+// RunCoreDNSMigrationCheck initializes checks related to CoreDNS migration.
+func RunCoreDNSMigrationCheck(client clientset.Interface, ignorePreflightErrors sets.String, dnsType kubeadmapi.DNSAddOnType) error {
+	if dnsType != kubeadmapi.CoreDNS {
+		return nil
+	}
+	migrationChecks := []preflight.Checker{
+		&CoreDNSCheck{
+			name:   "CoreDNSUnsupportedPlugins",
+			client: client,
+			f:      checkUnsupportedPlugins,
+		},
+		&CoreDNSCheck{
+			name:   "CoreDNSMigration",
+			client: client,
+			f:      checkMigration,
+		},
+	}
+
+	return preflight.RunChecks(migrationChecks, os.Stderr, ignorePreflightErrors)
+}
+
+// checkUnsupportedPlugins checks if there are any plugins included in the current configuration
+// that are unsupported for migration.
+func checkUnsupportedPlugins(client clientset.Interface) error {
+	klog.V(1).Infoln("validating if there are any unsupported CoreDNS plugins in the Corefile")
+	_, corefile, currentInstalledCoreDNSversion, err := dns.GetCoreDNSInfo(client)
+	if err != nil {
+		return err
+	}
+	unsupportedCoreDNS, err := migration.Unsupported(currentInstalledCoreDNSversion, kubeadmconstants.CoreDNSVersion, corefile)
+	if err != nil {
+		return err
+	}
+	if unsupportedCoreDNS != nil {
+		var UnsupportedPlugins, UnsupportedVersion string
+		for _, unsup := range unsupportedCoreDNS {
+			UnsupportedPlugins = unsup.Plugin
+			UnsupportedVersion = unsup.Version
+
+		}
+		if UnsupportedPlugins != "" || UnsupportedVersion != "" {
+			return errors.New("there are unsupported plugins in the CoreDNS Corefile")
+		}
+	}
+	return nil
+}
+
+// checkMigration validates if migration of the current CoreDNS ConfigMap is possible.
+func checkMigration(client clientset.Interface) error {
+	klog.V(1).Infoln("validating if migration can be done for the current CoreDNS release.")
+	_, corefile, currentInstalledCoreDNSversion, err := dns.GetCoreDNSInfo(client)
+	if err != nil {
+		return err
+	}
+
+	_, err = migration.Migrate(currentInstalledCoreDNSversion, kubeadmconstants.CoreDNSVersion, corefile, false)
+	if err != nil {
+		return err
+	}
+	return nil
+}