Merge pull request #92716 from rajansandeep/removefederation

[kubeadm]: Remove kube-dns translation for federation

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

@@ -51,7 +51,6 @@ const (
 	KubeDNSServiceAccountName  = "kube-dns"
 	kubeDNSStubDomain          = "stubDomains"
 	kubeDNSUpstreamNameservers = "upstreamNameservers"
-	kubeDNSFederation          = "federations"
 	unableToDecodeCoreDNS      = "unable to decode CoreDNS"
 	coreDNSReplicas            = 2
 	kubeDNSReplicas            = 1
@@ -226,16 +225,11 @@ func coreDNSAddon(cfg *kubeadmapi.ClusterConfiguration, client clientset.Interfa
 		return err
 	}
 	coreDNSDomain := cfg.Networking.DNSDomain
-	federations, err := translateFederationsofKubeDNSToCoreDNS(kubeDNSFederation, coreDNSDomain, kubeDNSConfigMap)
-	if err != nil {
-		return err
-	}
 
 	// Get the config file for CoreDNS
-	coreDNSConfigMapBytes, err := kubeadmutil.ParseTemplate(CoreDNSConfigMap, struct{ DNSDomain, UpstreamNameserver, Federation, StubDomain string }{
+	coreDNSConfigMapBytes, err := kubeadmutil.ParseTemplate(CoreDNSConfigMap, struct{ DNSDomain, UpstreamNameserver, StubDomain string }{
 		DNSDomain:          coreDNSDomain,
 		UpstreamNameserver: upstreamNameserver,
-		Federation:         federations,
 		StubDomain:         stubDomain,
 	})
 	if err != nil {
@@ -580,47 +574,6 @@ func translateUpstreamNameServerOfKubeDNSToUpstreamForwardCoreDNS(dataField stri
 	return "/etc/resolv.conf", nil
 }
 
-// translateFederationsofKubeDNSToCoreDNS translates Federations Data in kube-dns ConfigMap
-// to Federation for CoreDNS Corefile.
-func translateFederationsofKubeDNSToCoreDNS(dataField, coreDNSDomain string, kubeDNSConfigMap *v1.ConfigMap) (string, error) {
-	if kubeDNSConfigMap == nil {
-		return "", nil
-	}
-
-	if federation, ok := kubeDNSConfigMap.Data[dataField]; ok {
-		var (
-			federationStanza []interface{}
-			body             [][]string
-		)
-		federationData := make(map[string]string)
-
-		err := json.Unmarshal([]byte(federation), &federationData)
-		if err != nil {
-			return "", errors.Wrap(err, "failed to parse JSON from kube-dns ConfigMap")
-		}
-		fStanza := map[string]interface{}{}
-
-		for name, domain := range federationData {
-			body = append(body, []string{name, domain})
-		}
-		federationStanza = append(federationStanza, fStanza)
-		fStanza["keys"] = []string{"federation " + coreDNSDomain}
-		fStanza["body"] = body
-		stanzasBytes, err := json.Marshal(federationStanza)
-		if err != nil {
-			return "", err
-		}
-
-		corefileStanza, err := caddyfile.FromJSON(stanzasBytes)
-		if err != nil {
-			return "", err
-		}
-
-		return prepCorefileFormat(string(corefileStanza), 8), nil
-	}
-	return "", nil
-}
-
 // prepCorefileFormat indents the output of the Corefile caddytext and replaces tabs with spaces
 // to neatly format the configmap, making it readable.
 func prepCorefileFormat(s string, indentation int) string {

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

@@ -139,9 +139,8 @@ func TestCompileManifests(t *testing.T) {
 		{
 			name:     "CoreDNSConfigMap manifest",
 			manifest: CoreDNSConfigMap,
-			data: struct{ DNSDomain, Federation, UpstreamNameserver, StubDomain string }{
+			data: struct{ DNSDomain, UpstreamNameserver, StubDomain string }{
 				DNSDomain:          "foo",
-				Federation:         "foo",
 				UpstreamNameserver: "foo",
 				StubDomain:         "foo",
 			},
@@ -496,80 +495,6 @@ func TestTranslateUpstreamKubeDNSToCoreDNS(t *testing.T) {
 	}
 }
 
-func TestTranslateFederationKubeDNSToCoreDNS(t *testing.T) {
-	testCases := []struct {
-		name      string
-		configMap *v1.ConfigMap
-		expectOne string
-		expectTwo string
-	}{
-		{
-			name: "valid call",
-			configMap: &v1.ConfigMap{
-				ObjectMeta: metav1.ObjectMeta{
-					Name:      "kube-dns",
-					Namespace: "kube-system",
-				},
-				Data: map[string]string{
-					"federations":         `{"foo" : "foo.feddomain.com", "bar" : "bar.feddomain.com"}`,
-					"stubDomains":         `{"foo.com" : ["1.2.3.4:5300","3.3.3.3"], "my.cluster.local" : ["2.3.4.5"]}`,
-					"upstreamNameservers": `["8.8.8.8", "8.8.4.4"]`,
-				},
-			},
-
-			expectOne: `
-        federation cluster.local {
-           foo foo.feddomain.com
-           bar bar.feddomain.com
-        }`,
-			expectTwo: `
-        federation cluster.local {
-           bar bar.feddomain.com
-           foo foo.feddomain.com
-        }`,
-		},
-		{
-			name: "empty data",
-			configMap: &v1.ConfigMap{
-				ObjectMeta: metav1.ObjectMeta{
-					Name:      "kubedns",
-					Namespace: "kube-system",
-				},
-			},
-
-			expectOne: "",
-			expectTwo: "",
-		},
-		{
-			name: "missing federations data",
-			configMap: &v1.ConfigMap{
-				ObjectMeta: metav1.ObjectMeta{
-					Name:      "kube-dns",
-					Namespace: "kube-system",
-				},
-				Data: map[string]string{
-					"stubDomains":         `{"foo.com" : ["1.2.3.4:5300"], "my.cluster.local" : ["2.3.4.5"]}`,
-					"upstreamNameservers": `["8.8.8.8", "8.8.4.4"]`,
-				},
-			},
-
-			expectOne: "",
-			expectTwo: "",
-		},
-	}
-	for _, testCase := range testCases {
-		t.Run(testCase.name, func(t *testing.T) {
-			out, err := translateFederationsofKubeDNSToCoreDNS(kubeDNSFederation, "cluster.local", testCase.configMap)
-			if err != nil {
-				t.Errorf("unexpected error: %v", err)
-			}
-			if !strings.EqualFold(out, testCase.expectOne) && !strings.EqualFold(out, testCase.expectTwo) {
-				t.Errorf("expected to find %q or %q in output: %q", testCase.expectOne, testCase.expectTwo, out)
-			}
-		})
-	}
-}
-
 func TestDeploymentsHaveSystemClusterCriticalPriorityClassName(t *testing.T) {
 	replicas := int32(coreDNSReplicas)
 	testCases := []struct {

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

@@ -318,7 +318,7 @@ data:
            pods insecure
            fallthrough in-addr.arpa ip6.arpa
            ttl 30
-        }{{ .Federation }}
+        }
         prometheus :9153
         forward . {{ .UpstreamNameserver }}
         cache 30

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

@@ -17,12 +17,15 @@ limitations under the License.
 package upgrade
 
 import (
+	"context"
 	"fmt"
 	"os"
 
 	"github.com/coredns/corefile-migration/migration"
 	"github.com/pkg/errors"
 
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/util/sets"
 	clientset "k8s.io/client-go/kubernetes"
 	"k8s.io/klog/v2"
@@ -68,6 +71,11 @@ func RunCoreDNSMigrationCheck(client clientset.Interface, ignorePreflightErrors
 			client: client,
 			f:      checkMigration,
 		},
+		&CoreDNSCheck{
+			name:   "kubeDNSTranslation",
+			client: client,
+			f:      checkKubeDNSConfigMap,
+		},
 	}
 
 	return preflight.RunChecks(migrationChecks, os.Stderr, ignorePreflightErrors)
@@ -114,3 +122,21 @@ func checkMigration(client clientset.Interface) error {
 	}
 	return nil
 }
+
+// checkKubeDNSConfigMap checks if the translation of kube-dns to CoreDNS ConfigMap is supported
+func checkKubeDNSConfigMap(client clientset.Interface) error {
+	kubeDNSConfigMap, err := client.CoreV1().ConfigMaps(metav1.NamespaceSystem).Get(context.TODO(), kubeadmconstants.KubeDNSConfigMap, metav1.GetOptions{})
+	if err != nil && !apierrors.IsNotFound(err) {
+		return err
+	}
+	if kubeDNSConfigMap == nil {
+		return nil
+	}
+
+	if _, ok := kubeDNSConfigMap.Data["federations"]; ok {
+		klog.V(1).Infoln("CoreDNS no longer supports Federation and " +
+			"hence will not translate the federation data from kube-dns to CoreDNS ConfigMap")
+		return errors.Wrap(err, "kube-dns Federation data will not be translated")
+	}
+	return nil
+}