Merge pull request kubernetes#110566 from claudiubelu/unittests-5

Adds Pod DNS Policies support for Windows pods

Author: k8s-ci-robot

pkg/kubelet/network/dns/dns.go

@@ -59,9 +59,10 @@ const (
 
 // Configurer is used for setting up DNS resolver configuration when launching pods.
 type Configurer struct {
-	recorder record.EventRecorder
-	nodeRef  *v1.ObjectReference
-	nodeIPs  []net.IP
+	recorder         record.EventRecorder
+	getHostDNSConfig func(string) (*runtimeapi.DNSConfig, error)
+	nodeRef          *v1.ObjectReference
+	nodeIPs          []net.IP
 
 	// If non-nil, use this for container DNS server.
 	clusterDNS []net.IP
@@ -76,12 +77,13 @@ type Configurer struct {
 // NewConfigurer returns a DNS configurer for launching pods.
 func NewConfigurer(recorder record.EventRecorder, nodeRef *v1.ObjectReference, nodeIPs []net.IP, clusterDNS []net.IP, clusterDomain, resolverConfig string) *Configurer {
 	return &Configurer{
-		recorder:       recorder,
-		nodeRef:        nodeRef,
-		nodeIPs:        nodeIPs,
-		clusterDNS:     clusterDNS,
-		ClusterDomain:  clusterDomain,
-		ResolverConfig: resolverConfig,
+		recorder:         recorder,
+		getHostDNSConfig: getHostDNSConfig,
+		nodeRef:          nodeRef,
+		nodeIPs:          nodeIPs,
+		clusterDNS:       clusterDNS,
+		ClusterDomain:    clusterDomain,
+		ResolverConfig:   resolverConfig,
 	}
 }
 
@@ -279,28 +281,6 @@ func parseResolvConf(reader io.Reader) (nameservers []string, searches []string,
 	return nameservers, searches, options, utilerrors.NewAggregate(allErrors)
 }
 
-func (c *Configurer) getHostDNSConfig() (*runtimeapi.DNSConfig, error) {
-	var hostDNS, hostSearch, hostOptions []string
-	// Get host DNS settings
-	if c.ResolverConfig != "" {
-		f, err := os.Open(c.ResolverConfig)
-		if err != nil {
-			return nil, err
-		}
-		defer f.Close()
-
-		hostDNS, hostSearch, hostOptions, err = parseResolvConf(f)
-		if err != nil {
-			return nil, err
-		}
-	}
-	return &runtimeapi.DNSConfig{
-		Servers:  hostDNS,
-		Searches: hostSearch,
-		Options:  hostOptions,
-	}, nil
-}
-
 func getPodDNSType(pod *v1.Pod) (podDNSType, error) {
 	dnsPolicy := pod.Spec.DNSPolicy
 	switch dnsPolicy {
@@ -384,7 +364,7 @@ func appendDNSConfig(existingDNSConfig *runtimeapi.DNSConfig, dnsConfig *v1.PodD
 
 // GetPodDNS returns DNS settings for the pod.
 func (c *Configurer) GetPodDNS(pod *v1.Pod) (*runtimeapi.DNSConfig, error) {
-	dnsConfig, err := c.getHostDNSConfig()
+	dnsConfig, err := c.getHostDNSConfig(c.ResolverConfig)
 	if err != nil {
 		return nil, err
 	}

pkg/kubelet/network/dns/dns_other.go

@@ -0,0 +1,53 @@
+//go:build !windows
+// +build !windows
+
+/*
+Copyright 2023 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 dns
+
+import (
+	"fmt"
+	"os"
+
+	runtimeapi "k8s.io/cri-api/pkg/apis/runtime/v1"
+	"k8s.io/klog/v2"
+)
+
+func getHostDNSConfig(resolverConfig string) (*runtimeapi.DNSConfig, error) {
+	var hostDNS, hostSearch, hostOptions []string
+	// Get host DNS settings
+	if resolverConfig != "" {
+		f, err := os.Open(resolverConfig)
+		if err != nil {
+			klog.ErrorS(err, "Could not open resolv conf file.")
+			return nil, err
+		}
+		defer f.Close()
+
+		hostDNS, hostSearch, hostOptions, err = parseResolvConf(f)
+		if err != nil {
+			err := fmt.Errorf("Encountered error while parsing resolv conf file. Error: %w", err)
+			klog.ErrorS(err, "Could not parse resolv conf file.")
+			return nil, err
+		}
+	}
+	return &runtimeapi.DNSConfig{
+		Servers:  hostDNS,
+		Searches: hostSearch,
+		Options:  hostOptions,
+	}, nil
+}

pkg/kubelet/network/dns/dns_other_test.go

@@ -0,0 +1,57 @@
+//go:build !windows
+// +build !windows
+
+/*
+Copyright 2023 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 dns
+
+import (
+	"fmt"
+	"os"
+	"testing"
+)
+
+var (
+	defaultResolvConf = "/etc/resolv.conf"
+	// configurer.getHostDNSConfig is faked on Windows, while it is not faked on Linux.
+	fakeGetHostDNSConfigCustom = getHostDNSConfig
+)
+
+// getResolvConf returns a temporary resolv.conf file containing the testHostNameserver nameserver and
+// testHostDomain search field, and a cleanup function for the temporary file.
+func getResolvConf(t *testing.T) (string, func()) {
+	resolvConfContent := []byte(fmt.Sprintf("nameserver %s\nsearch %s\n", testHostNameserver, testHostDomain))
+	tmpfile, err := os.CreateTemp("", "tmpResolvConf")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	cleanup := func() {
+		os.Remove(tmpfile.Name())
+	}
+
+	if _, err := tmpfile.Write(resolvConfContent); err != nil {
+		cleanup()
+		t.Fatal(err)
+	}
+	if err := tmpfile.Close(); err != nil {
+		cleanup()
+		t.Fatal(err)
+	}
+
+	return tmpfile.Name(), cleanup
+}

pkg/kubelet/network/dns/dns_test.go

@@ -19,8 +19,6 @@ package dns
 import (
 	"fmt"
 	"net"
-	"os"
-	goruntime "runtime"
 	"strconv"
 	"strings"
 	"testing"
@@ -42,7 +40,10 @@ import (
 )
 
 var (
-	fetchEvent = func(recorder *record.FakeRecorder) string {
+	// testHostNameserver and testHostDomain are also being used in dns_windows_test.go.
+	testHostNameserver = "8.8.8.8"
+	testHostDomain     = "host.domain"
+	fetchEvent         = func(recorder *record.FakeRecorder) string {
 		select {
 		case event := <-recorder.Events:
 			return event
@@ -457,26 +458,19 @@ func TestGetPodDNS(t *testing.T) {
 	testCases := []struct {
 		desc              string
 		expandedDNSConfig bool
-		skipOnWindows     bool
 	}{
 		{
 			desc:              "Not ExpandedDNSConfig",
 			expandedDNSConfig: false,
-			skipOnWindows:     true,
 		},
 		{
 			desc:              "ExpandedDNSConfig",
 			expandedDNSConfig: true,
-			skipOnWindows:     true,
 		},
 	}
 
 	for _, tc := range testCases {
 		t.Run(tc.desc, func(t *testing.T) {
-			// Skip tests that fail on Windows, as discussed during the SIG Testing meeting from January 10, 2023
-			if tc.skipOnWindows && goruntime.GOOS == "windows" {
-				t.Skip("Skipping test that fails on Windows")
-			}
 			defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.ExpandedDNSConfig, tc.expandedDNSConfig)()
 			testGetPodDNS(t)
 		})
@@ -541,8 +535,7 @@ func testGetPodDNS(t *testing.T) {
 		t.Errorf("expected search \".\", got %+v", options[3].DNSSearch)
 	}
 
-	testResolverConfig := "/etc/resolv.conf"
-	configurer = NewConfigurer(recorder, nodeRef, nil, testClusterDNS, testClusterDNSDomain, testResolverConfig)
+	configurer = NewConfigurer(recorder, nodeRef, nil, testClusterDNS, testClusterDNSDomain, defaultResolvConf)
 	for i, pod := range pods {
 		var err error
 		dnsConfig, err := configurer.GetPodDNS(pod)
@@ -599,8 +592,6 @@ func TestGetPodDNSCustom(t *testing.T) {
 	testSvcDomain := fmt.Sprintf("svc.%s", testClusterDNSDomain)
 	testNsSvcDomain := fmt.Sprintf("%s.svc.%s", testPodNamespace, testClusterDNSDomain)
 	testNdotsOptionValue := "3"
-	testHostNameserver := "8.8.8.8"
-	testHostDomain := "host.domain"
 
 	testPod := &v1.Pod{
 		ObjectMeta: metav1.ObjectMeta{
@@ -609,20 +600,11 @@ func TestGetPodDNSCustom(t *testing.T) {
 		},
 	}
 
-	resolvConfContent := []byte(fmt.Sprintf("nameserver %s\nsearch %s\n", testHostNameserver, testHostDomain))
-	tmpfile, err := os.CreateTemp("", "tmpResolvConf")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer os.Remove(tmpfile.Name())
-	if _, err := tmpfile.Write(resolvConfContent); err != nil {
-		t.Fatal(err)
-	}
-	if err := tmpfile.Close(); err != nil {
-		t.Fatal(err)
-	}
+	resolvConf, cleanup := getResolvConf(t)
+	defer cleanup()
 
-	configurer := NewConfigurer(recorder, nodeRef, nil, []net.IP{netutils.ParseIPSloppy(testClusterNameserver)}, testClusterDNSDomain, tmpfile.Name())
+	configurer := NewConfigurer(recorder, nodeRef, nil, []net.IP{netutils.ParseIPSloppy(testClusterNameserver)}, testClusterDNSDomain, resolvConf)
+	configurer.getHostDNSConfig = fakeGetHostDNSConfigCustom
 
 	testCases := []struct {
 		desc              string