kube-dns configmap translate

cmd/kubeadm/app/phases/addons/dns/BUILD

@@ -19,7 +19,9 @@ go_test(
         "//cmd/kubeadm/app/util:go_default_library",
         "//pkg/apis/core:go_default_library",
         "//pkg/util/version:go_default_library",
+        "//vendor/k8s.io/api/core/v1: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/fake:go_default_library",
         "//vendor/k8s.io/client-go/testing:go_default_library",
@@ -41,6 +43,7 @@ go_library(
         "//cmd/kubeadm/app/util:go_default_library",
         "//cmd/kubeadm/app/util/apiclient:go_default_library",
         "//pkg/api/legacyscheme:go_default_library",
+        "//pkg/kubelet/types:go_default_library",
         "//pkg/util/version:go_default_library",
         "//vendor/k8s.io/api/apps/v1:go_default_library",
         "//vendor/k8s.io/api/core/v1:go_default_library",

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

@@ -18,7 +18,11 @@ package dns
 
 import (
 	"fmt"
+
 	"runtime"
+	"strings"
+
+	"encoding/json"
 
 	apps "k8s.io/api/apps/v1"
 	"k8s.io/api/core/v1"
@@ -33,12 +37,15 @@ import (
 	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
 	"k8s.io/kubernetes/cmd/kubeadm/app/util/apiclient"
 	"k8s.io/kubernetes/pkg/api/legacyscheme"
+	kubetypes "k8s.io/kubernetes/pkg/kubelet/types"
 	"k8s.io/kubernetes/pkg/util/version"
 )
 
 const (
 	// KubeDNSServiceAccountName describes the name of the ServiceAccount for the kube-dns addon
 	KubeDNSServiceAccountName  = "kube-dns"
+	kubeDNSStubDomain          = "stubDomains"
+	kubeDNSUpstreamNameservers = "upstreamNameservers"
 )
 
 // EnsureDNSAddon creates the kube-dns or CoreDNS addon
@@ -139,11 +146,27 @@ func coreDNSAddon(cfg *kubeadmapi.MasterConfiguration, client clientset.Interfac
 	if err != nil {
 		return fmt.Errorf("error when parsing CoreDNS deployment template: %v", err)
 	}
+	kubeDNSConfigMap, err := client.CoreV1().ConfigMaps(metav1.NamespaceSystem).Get(kubeadmconstants.KubeDNS, metav1.GetOptions{})
+	if err != nil && !apierrors.IsNotFound(err) {
+		return err
+	}
+
+	stubDomain, err := translateStubDomainOfKubeDNSToProxyCoreDNS(kubeDNSStubDomain, kubeDNSConfigMap)
+	if err != nil {
+		return err
+	}
+
+	upstreamNameserver, err := translateUpstreamNameServerOfKubeDNSToUpstreamProxyCoreDNS(kubeDNSUpstreamNameservers, kubeDNSConfigMap)
+	if err != nil {
+		return err
+	}
 
 	// Get the config file for CoreDNS
-	coreDNSConfigMapBytes, err := kubeadmutil.ParseTemplate(CoreDNSConfigMap, struct{ DNSDomain, ServiceCIDR string }{
+	coreDNSConfigMapBytes, err := kubeadmutil.ParseTemplate(CoreDNSConfigMap, struct{ DNSDomain, ServiceCIDR, UpstreamNameserver, StubDomain string }{
 		ServiceCIDR:        cfg.Networking.ServiceSubnet,
 		DNSDomain:          cfg.Networking.DNSDomain,
+		UpstreamNameserver: upstreamNameserver,
+		StubDomain:         stubDomain,
 	})
 	if err != nil {
 		return fmt.Errorf("error when parsing CoreDNS configMap template: %v", err)
@@ -244,3 +267,40 @@ func createDNSService(dnsService *v1.Service, serviceBytes []byte, client client
 	}
 	return nil
 }
+
+// translateStubDomainOfKubeDNSToProxyCoreDNS translates StubDomain Data in kube-dns ConfigMap
+// in the form of Proxy for the CoreDNS Corefile.
+func translateStubDomainOfKubeDNSToProxyCoreDNS(dataField string, kubeDNSConfigMap *v1.ConfigMap) (string, error) {
+	if proxy, ok := kubeDNSConfigMap.Data[dataField]; ok {
+		stubDomainData := make(map[string][]string)
+		proxyStanzaList := coreDNSProxyStanzaPrefix
+
+		err := json.Unmarshal([]byte(proxy), &stubDomainData)
+		if err != nil {
+			return "", fmt.Errorf("failed to parse JSON from 'kube-dns ConfigMap: %v", err)
+		}
+
+		for domain, proxyIP := range stubDomainData {
+			proxyStanzaList = proxyStanzaList + domain + coreDNSProxyDefaultPort + coreDNSCorefileDefaultData + strings.Join(proxyIP, " ") + coreDNSProxyStanzaSuffix
+		}
+		return proxyStanzaList, nil
+	}
+	return "", nil
+}
+
+// translateUpstreamNameServerOfKubeDNSToUpstreamProxyCoreDNS translates UpstreamNameServer Data in kube-dns ConfigMap
+// in the form of Proxy for the CoreDNS Corefile.
+func translateUpstreamNameServerOfKubeDNSToUpstreamProxyCoreDNS(dataField string, kubeDNSConfigMap *v1.ConfigMap) (string, error) {
+	if upstreamValues, ok := kubeDNSConfigMap.Data[dataField]; ok {
+		var upstreamProxyIP []string
+
+		err := json.Unmarshal([]byte(upstreamValues), &upstreamProxyIP)
+		if err != nil {
+			return "", fmt.Errorf("failed to parse JSON from 'kube-dns ConfigMap: %v", err)
+		}
+
+		coreDNSProxyStanzaList := strings.Join(upstreamProxyIP, " ")
+		return coreDNSProxyStanzaList, nil
+	}
+	return kubetypes.ResolvConfDefault, nil
+}

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

@@ -17,9 +17,12 @@ limitations under the License.
 package dns
 
 import (
+	"strings"
 	"testing"
 
+	"k8s.io/api/core/v1"
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	clientsetfake "k8s.io/client-go/kubernetes/fake"
 	core "k8s.io/client-go/testing"
@@ -127,9 +130,11 @@ func TestCompileManifests(t *testing.T) {
 		},
 		{
 			manifest: CoreDNSConfigMap,
-			data: struct{ DNSDomain, ServiceCIDR string }{
+			data: struct{ DNSDomain, ServiceCIDR, UpstreamNameserver, StubDomain string }{
 				DNSDomain:          "foo",
 				ServiceCIDR:        "foo",
+				UpstreamNameserver: "foo",
+				StubDomain:         "foo",
 			},
 			expected: true,
 		},
@@ -175,3 +180,134 @@ func TestGetDNSIP(t *testing.T) {
 		}
 	}
 }
+
+func TestTranslateStubDomainKubeDNSToCoreDNS(t *testing.T) {
+	testCases := []struct {
+		configMap *v1.ConfigMap
+		expect    string
+	}{
+		{
+			configMap: &v1.ConfigMap{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:      "kube-dns",
+					Namespace: "kube-system",
+				},
+				Data: map[string]string{
+					"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"]`,
+				},
+			},
+
+			expect: `
+    foo.com:53 {
+        errors
+        cache 30
+        proxy . 1.2.3.4:5300 3.3.3.3
+    }
+    my.cluster.local:53 {
+        errors
+        cache 30
+        proxy . 2.3.4.5
+    }
+    `,
+		},
+		{
+			configMap: &v1.ConfigMap{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:      "kubedns",
+					Namespace: "kube-system",
+				},
+			},
+
+			expect: "",
+		},
+		{
+			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"]`,
+				},
+			},
+
+			expect: `
+    foo.com:53 {
+        errors
+        cache 30
+        proxy . 1.2.3.4:5300
+    }
+    my.cluster.local:53 {
+        errors
+        cache 30
+        proxy . 2.3.4.5
+    }
+    `,
+		},
+	}
+	for _, testCase := range testCases {
+		out, err := translateStubDomainOfKubeDNSToProxyCoreDNS(kubeDNSStubDomain, testCase.configMap)
+		if err != nil {
+			t.Errorf("unexpected error: %v", err)
+		}
+		if !strings.Contains(out, testCase.expect) {
+			t.Errorf("expected to find %q in output: %q", testCase.expect, out)
+		}
+	}
+}
+
+func TestTranslateUpstreamKubeDNSToCoreDNS(t *testing.T) {
+	testCases := []struct {
+		configMap *v1.ConfigMap
+		expect    string
+	}{
+		{
+			configMap: &v1.ConfigMap{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:      "kube-dns",
+					Namespace: "kube-system",
+				},
+			},
+
+			expect: "/etc/resolv.conf",
+		},
+		{
+			configMap: &v1.ConfigMap{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:      "kubedns",
+					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", "4.4.4.4"]`,
+				},
+			},
+
+			expect: "8.8.8.8 8.8.4.4 4.4.4.4",
+		},
+		{
+			configMap: &v1.ConfigMap{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:      "kubedns",
+					Namespace: "kube-system",
+				},
+				Data: map[string]string{
+					"upstreamNameservers": `["8.8.8.8", "8.8.4.4"]`,
+				},
+			},
+
+			expect: "8.8.8.8 8.8.4.4",
+		},
+	}
+	for _, testCase := range testCases {
+		out, err := translateUpstreamNameServerOfKubeDNSToUpstreamProxyCoreDNS(kubeDNSUpstreamNameservers, testCase.configMap)
+		if err != nil {
+			t.Errorf("unexpected error: %v", err)
+		}
+		if !strings.Contains(out, testCase.expect) {
+			t.Errorf("expected to find %q in output: %q", testCase.expect, out)
+		}
+	}
+}

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

@@ -309,13 +309,13 @@ data:
         health
         kubernetes {{ .DNSDomain }} {{ .ServiceCIDR }} {
            pods insecure
-           upstream /etc/resolv.conf
+           upstream {{ .UpstreamNameserver }}
            fallthrough in-addr.arpa ip6.arpa
         }
         prometheus :9153
-        proxy . /etc/resolv.conf
+        proxy . {{ .UpstreamNameserver }}
         cache 30
-    }
+    }{{ .StubDomain }}
 `
 	// CoreDNSClusterRole is the CoreDNS ClusterRole manifest
 	CoreDNSClusterRole = `
@@ -358,4 +358,15 @@ metadata:
   name: coredns
   namespace: kube-system
 `
+	// coreDNSProxyDefaultPort, coreDNSCorefileDefaultData, coreDNSProxyStanzaSuffix is used in the translation of configMap of kube-dns to CoreDNS.
+	coreDNSProxyStanzaPrefix = `
+    `
+	coreDNSProxyDefaultPort    = `:53`
+	coreDNSCorefileDefaultData = ` {
+        errors
+        cache 30
+        proxy . `
+	coreDNSProxyStanzaSuffix = `
+    }
+    `
 )