Support copying options in resolv.conf into pod sandbox when dnsPolicy is Default

pkg/kubelet/container/helpers.go

@@ -47,7 +47,7 @@ type HandlerRunner interface {
 // able to get necessary informations like the RunContainerOptions, DNS settings, Host IP.
 type RuntimeHelper interface {
 	GenerateRunContainerOptions(pod *v1.Pod, container *v1.Container, podIP string) (contOpts *RunContainerOptions, err error)
-	GetClusterDNS(pod *v1.Pod) (dnsServers []string, dnsSearches []string, useClusterFirstPolicy bool, err error)
+	GetClusterDNS(pod *v1.Pod) (dnsServers []string, dnsSearches []string, dnsOptions []string, useClusterFirstPolicy bool, err error)
 	// GetPodCgroupParent returns the CgroupName identifer, and its literal cgroupfs form on the host
 	// of a pod.
 	GetPodCgroupParent(pod *v1.Pod) string

pkg/kubelet/container/testing/fake_runtime_helper.go

@@ -44,8 +44,8 @@ func (f *FakeRuntimeHelper) GetPodCgroupParent(pod *v1.Pod) string {
 	return ""
 }
 
-func (f *FakeRuntimeHelper) GetClusterDNS(pod *v1.Pod) ([]string, []string, bool, error) {
-	return f.DNSServers, f.DNSSearches, false, f.Err
+func (f *FakeRuntimeHelper) GetClusterDNS(pod *v1.Pod) ([]string, []string, []string, bool, error) {
+	return f.DNSServers, f.DNSSearches, nil, false, f.Err
 }
 
 // This is not used by docker runtime.

pkg/kubelet/kubelet.go

@@ -1401,21 +1401,21 @@ func (kl *Kubelet) GetKubeClient() clientset.Interface {
 	return kl.kubeClient
 }
 
-// GetClusterDNS returns a list of the DNS servers and a list of the DNS search
-// domains of the cluster.
-func (kl *Kubelet) GetClusterDNS(pod *v1.Pod) ([]string, []string, bool, error) {
-	var hostDNS, hostSearch []string
+// GetClusterDNS returns a list of the DNS servers, a list of the DNS search
+// domains of the cluster, and a list of resolv.conf options.
+func (kl *Kubelet) GetClusterDNS(pod *v1.Pod) ([]string, []string, []string, bool, error) {
+	var hostDNS, hostSearch, hostOptions []string
 	// Get host DNS settings
 	if kl.resolverConfig != "" {
 		f, err := os.Open(kl.resolverConfig)
 		if err != nil {
-			return nil, nil, false, err
+			return nil, nil, nil, false, err
 		}
 		defer f.Close()
 
-		hostDNS, hostSearch, err = kl.parseResolvConf(f)
+		hostDNS, hostSearch, hostOptions, err = kl.parseResolvConf(f)
 		if err != nil {
-			return nil, nil, false, err
+			return nil, nil, nil, false, err
 		}
 	}
 	useClusterFirstPolicy := ((pod.Spec.DNSPolicy == v1.DNSClusterFirst && !kubecontainer.IsHostNetworkPod(pod)) || pod.Spec.DNSPolicy == v1.DNSClusterFirstWithHostNet)
@@ -1444,7 +1444,7 @@ func (kl *Kubelet) GetClusterDNS(pod *v1.Pod) ([]string, []string, bool, error)
 		} else {
 			hostSearch = kl.formDNSSearchForDNSDefault(hostSearch, pod)
 		}
-		return hostDNS, hostSearch, useClusterFirstPolicy, nil
+		return hostDNS, hostSearch, hostOptions, useClusterFirstPolicy, nil
 	}
 
 	// for a pod with DNSClusterFirst policy, the cluster DNS server is the only nameserver configured for
@@ -1456,7 +1456,7 @@ func (kl *Kubelet) GetClusterDNS(pod *v1.Pod) ([]string, []string, bool, error)
 	}
 	dnsSearch := kl.formDNSSearch(hostSearch, pod)
 
-	return dns, dnsSearch, useClusterFirstPolicy, nil
+	return dns, dnsSearch, hostOptions, useClusterFirstPolicy, nil
 }
 
 // syncPod is the transaction script for the sync of a single pod.
@@ -2237,7 +2237,7 @@ func (kl *Kubelet) setupDNSinContainerizedMounter(mounterPath string) {
 		if err != nil {
 			glog.Error("Could not open resolverConf file")
 		} else {
-			_, hostSearch, err := kl.parseResolvConf(f)
+			_, hostSearch, _, err := kl.parseResolvConf(f)
 			if err != nil {
 				glog.Errorf("Error for parsing the reslov.conf file: %v", err)
 			} else {

pkg/kubelet/kubelet_network.go

@@ -169,7 +169,7 @@ func (kl *Kubelet) checkLimitsForResolvConf() {
 	}
 	defer f.Close()
 
-	_, hostSearch, err := kl.parseResolvConf(f)
+	_, hostSearch, _, err := kl.parseResolvConf(f)
 	if err != nil {
 		kl.recorder.Event(kl.nodeRef, v1.EventTypeWarning, "checkLimitsForResolvConf", err.Error())
 		glog.Error("checkLimitsForResolvConf: " + err.Error())
@@ -200,12 +200,12 @@ func (kl *Kubelet) checkLimitsForResolvConf() {
 }
 
 // parseResolveConf reads a resolv.conf file from the given reader, and parses
-// it into nameservers and searches, possibly returning an error.
+// it into nameservers, searches and options, possibly returning an error.
 // TODO: move to utility package
-func (kl *Kubelet) parseResolvConf(reader io.Reader) (nameservers []string, searches []string, err error) {
+func (kl *Kubelet) parseResolvConf(reader io.Reader) (nameservers []string, searches []string, options []string, err error) {
 	file, err := ioutil.ReadAll(reader)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, nil, err
 	}
 
 	// Lines of the form "nameserver 1.2.3.4" accumulate.
@@ -214,6 +214,10 @@ func (kl *Kubelet) parseResolvConf(reader io.Reader) (nameservers []string, sear
 	// Lines of the form "search example.com" overrule - last one wins.
 	searches = []string{}
 
+	// Lines of the form "option ndots:5 attempts:2" overrule - last one wins.
+	// Each option is recorded as an element in the array.
+	options = []string{}
+
 	lines := strings.Split(string(file), "\n")
 	for l := range lines {
 		trimmed := strings.TrimSpace(lines[l])
@@ -230,13 +234,16 @@ func (kl *Kubelet) parseResolvConf(reader io.Reader) (nameservers []string, sear
 		if fields[0] == "search" {
 			searches = fields[1:]
 		}
+		if fields[0] == "options" {
+			options = fields[1:]
+		}
 	}
 
 	// There used to be code here to scrub DNS for each cloud, but doesn't
 	// make sense anymore since cloudproviders are being factored out.
 	// contact @thockin or @wlan0 for more information
 
-	return nameservers, searches, nil
+	return nameservers, searches, options, nil
 }
 
 // syncNetworkStatus updates the network state

pkg/kubelet/kubelet_network_test.go

@@ -74,39 +74,44 @@ func TestParseResolvConf(t *testing.T) {
 		data        string
 		nameservers []string
 		searches    []string
+		options     []string
 	}{
-		{"", []string{}, []string{}},
-		{" ", []string{}, []string{}},
-		{"\n", []string{}, []string{}},
-		{"\t\n\t", []string{}, []string{}},
-		{"#comment\n", []string{}, []string{}},
-		{" #comment\n", []string{}, []string{}},
-		{"#comment\n#comment", []string{}, []string{}},
-		{"#comment\nnameserver", []string{}, []string{}},
-		{"#comment\nnameserver\nsearch", []string{}, []string{}},
-		{"nameserver 1.2.3.4", []string{"1.2.3.4"}, []string{}},
-		{" nameserver 1.2.3.4", []string{"1.2.3.4"}, []string{}},
-		{"\tnameserver 1.2.3.4", []string{"1.2.3.4"}, []string{}},
-		{"nameserver\t1.2.3.4", []string{"1.2.3.4"}, []string{}},
-		{"nameserver \t 1.2.3.4", []string{"1.2.3.4"}, []string{}},
-		{"nameserver 1.2.3.4\nnameserver 5.6.7.8", []string{"1.2.3.4", "5.6.7.8"}, []string{}},
-		{"nameserver 1.2.3.4 #comment", []string{"1.2.3.4"}, []string{}},
-		{"search foo", []string{}, []string{"foo"}},
-		{"search foo bar", []string{}, []string{"foo", "bar"}},
-		{"search foo bar bat\n", []string{}, []string{"foo", "bar", "bat"}},
-		{"search foo\nsearch bar", []string{}, []string{"bar"}},
-		{"nameserver 1.2.3.4\nsearch foo bar", []string{"1.2.3.4"}, []string{"foo", "bar"}},
-		{"nameserver 1.2.3.4\nsearch foo\nnameserver 5.6.7.8\nsearch bar", []string{"1.2.3.4", "5.6.7.8"}, []string{"bar"}},
-		{"#comment\nnameserver 1.2.3.4\n#comment\nsearch foo\ncomment", []string{"1.2.3.4"}, []string{"foo"}},
+		{"", []string{}, []string{}, []string{}},
+		{" ", []string{}, []string{}, []string{}},
+		{"\n", []string{}, []string{}, []string{}},
+		{"\t\n\t", []string{}, []string{}, []string{}},
+		{"#comment\n", []string{}, []string{}, []string{}},
+		{" #comment\n", []string{}, []string{}, []string{}},
+		{"#comment\n#comment", []string{}, []string{}, []string{}},
+		{"#comment\nnameserver", []string{}, []string{}, []string{}},
+		{"#comment\nnameserver\nsearch", []string{}, []string{}, []string{}},
+		{"nameserver 1.2.3.4", []string{"1.2.3.4"}, []string{}, []string{}},
+		{" nameserver 1.2.3.4", []string{"1.2.3.4"}, []string{}, []string{}},
+		{"\tnameserver 1.2.3.4", []string{"1.2.3.4"}, []string{}, []string{}},
+		{"nameserver\t1.2.3.4", []string{"1.2.3.4"}, []string{}, []string{}},
+		{"nameserver \t 1.2.3.4", []string{"1.2.3.4"}, []string{}, []string{}},
+		{"nameserver 1.2.3.4\nnameserver 5.6.7.8", []string{"1.2.3.4", "5.6.7.8"}, []string{}, []string{}},
+		{"nameserver 1.2.3.4 #comment", []string{"1.2.3.4"}, []string{}, []string{}},
+		{"search foo", []string{}, []string{"foo"}, []string{}},
+		{"search foo bar", []string{}, []string{"foo", "bar"}, []string{}},
+		{"search foo bar bat\n", []string{}, []string{"foo", "bar", "bat"}, []string{}},
+		{"search foo\nsearch bar", []string{}, []string{"bar"}, []string{}},
+		{"nameserver 1.2.3.4\nsearch foo bar", []string{"1.2.3.4"}, []string{"foo", "bar"}, []string{}},
+		{"nameserver 1.2.3.4\nsearch foo\nnameserver 5.6.7.8\nsearch bar", []string{"1.2.3.4", "5.6.7.8"}, []string{"bar"}, []string{}},
+		{"#comment\nnameserver 1.2.3.4\n#comment\nsearch foo\ncomment", []string{"1.2.3.4"}, []string{"foo"}, []string{}},
+		{"options ndots:5 attempts:2", []string{}, []string{}, []string{"ndots:5", "attempts:2"}},
+		{"options ndots:1\noptions ndots:5 attempts:3", []string{}, []string{}, []string{"ndots:5", "attempts:3"}},
+		{"nameserver 1.2.3.4\nsearch foo\nnameserver 5.6.7.8\nsearch bar\noptions ndots:5 attempts:4", []string{"1.2.3.4", "5.6.7.8"}, []string{"bar"}, []string{"ndots:5", "attempts:4"}},
 	}
 	testKubelet := newTestKubelet(t, false /* controllerAttachDetachEnabled */)
 	defer testKubelet.Cleanup()
 	kubelet := testKubelet.kubelet
 	for i, tc := range testCases {
-		ns, srch, err := kubelet.parseResolvConf(strings.NewReader(tc.data))
+		ns, srch, opts, err := kubelet.parseResolvConf(strings.NewReader(tc.data))
 		require.NoError(t, err)
 		assert.EqualValues(t, tc.nameservers, ns, "test case [%d]: name servers", i)
 		assert.EqualValues(t, tc.searches, srch, "test case [%d] searches", i)
+		assert.EqualValues(t, tc.options, opts, "test case [%d] options", i)
 	}
 }
 

pkg/kubelet/kubelet_test.go

@@ -2194,7 +2194,7 @@ func TestGetClusterDNS(t *testing.T) {
 	}, 4)
 	for i, pod := range pods {
 		var err error
-		options[i].DNS, options[i].DNSSearch, _, err = kubelet.GetClusterDNS(pod)
+		options[i].DNS, options[i].DNSSearch, _, _, err = kubelet.GetClusterDNS(pod)
 		if err != nil {
 			t.Fatalf("failed to generate container options: %v", err)
 		}
@@ -2227,7 +2227,7 @@ func TestGetClusterDNS(t *testing.T) {
 	kubelet.resolverConfig = "/etc/resolv.conf"
 	for i, pod := range pods {
 		var err error
-		options[i].DNS, options[i].DNSSearch, _, err = kubelet.GetClusterDNS(pod)
+		options[i].DNS, options[i].DNSSearch, _, _, err = kubelet.GetClusterDNS(pod)
 		if err != nil {
 			t.Fatalf("failed to generate container options: %v", err)
 		}

pkg/kubelet/kuberuntime/kuberuntime_sandbox.go

@@ -74,14 +74,16 @@ func (m *kubeGenericRuntimeManager) generatePodSandboxConfig(pod *v1.Pod, attemp
 		Annotations: newPodAnnotations(pod),
 	}
 
-	dnsServers, dnsSearches, useClusterFirstPolicy, err := m.runtimeHelper.GetClusterDNS(pod)
+	dnsServers, dnsSearches, dnsOptions, useClusterFirstPolicy, err := m.runtimeHelper.GetClusterDNS(pod)
 	if err != nil {
 		return nil, err
 	}
 	podSandboxConfig.DnsConfig = &runtimeapi.DNSConfig{
 		Servers:  dnsServers,
 		Searches: dnsSearches,
+		Options:  dnsOptions,
 	}
+
 	if useClusterFirstPolicy {
 		podSandboxConfig.DnsConfig.Options = defaultDNSOptions
 	}

pkg/kubelet/rkt/rkt.go

@@ -1041,7 +1041,7 @@ func (r *Runtime) generateRunCommand(pod *v1.Pod, uuid, networkNamespaceID strin
 		}
 	} else {
 		// Setup DNS.
-		dnsServers, dnsSearches, _, err := r.runtimeHelper.GetClusterDNS(pod)
+		dnsServers, dnsSearches, _, _, err := r.runtimeHelper.GetClusterDNS(pod)
 		if err != nil {
 			return "", err
 		}