feat: add support for disabling search domains

This adds the option to toggle the automatic creation of search domains. Signed-off-by: Bᴇʀɴᴅ Sᴄʜᴏʀɢᴇʀs <me@bjw-s.dev> Signed-off-by: Andrey Smirnov <andrey.smirnov@talos-systems.com>
siderolabs · May 23, 2022 · f03002e · f03002e
1 parent a1b6f21
commit f03002e
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Showing 7 changed files with 57 additions and 5 deletions.
diff --git a/internal/app/machined/pkg/controllers/network/etcfile.go b/internal/app/machined/pkg/controllers/network/etcfile.go
@@ -129,7 +129,7 @@ func (ctrl *EtcFileController) Run(ctx context.Context, r controller.Runtime, lo
 		if resolverStatus != nil {
 			if err = r.Modify(ctx, files.NewEtcFileSpec(files.NamespaceName, "resolv.conf"),
 				func(r resource.Resource) error {
-					r.(*files.EtcFileSpec).TypedSpec().Contents = ctrl.renderResolvConf(resolverStatus, hostnameStatus)
+					r.(*files.EtcFileSpec).TypedSpec().Contents = ctrl.renderResolvConf(resolverStatus, hostnameStatus, cfgProvider)
 					r.(*files.EtcFileSpec).TypedSpec().Mode = 0o644
 
 					return nil
@@ -152,7 +152,7 @@ func (ctrl *EtcFileController) Run(ctx context.Context, r controller.Runtime, lo
 	}
 }
 
-func (ctrl *EtcFileController) renderResolvConf(resolverStatus *network.ResolverStatusSpec, hostnameStatus *network.HostnameStatusSpec) []byte {
+func (ctrl *EtcFileController) renderResolvConf(resolverStatus *network.ResolverStatusSpec, hostnameStatus *network.HostnameStatusSpec, cfgProvider talosconfig.Provider) []byte {
 	var buf bytes.Buffer
 
 	for i, resolver := range resolverStatus.DNSServers {
@@ -164,7 +164,12 @@ func (ctrl *EtcFileController) renderResolvConf(resolverStatus *network.Resolver
 		fmt.Fprintf(&buf, "nameserver %s\n", resolver)
 	}
 
-	if hostnameStatus != nil && hostnameStatus.Domainname != "" {
+	var disableSearchDomain bool
+	if cfgProvider != nil {
+		disableSearchDomain = cfgProvider.Machine().Network().DisableSearchDomain()
+	}
+
+	if !disableSearchDomain && hostnameStatus != nil && hostnameStatus.Domainname != "" {
 		fmt.Fprintf(&buf, "\nsearch %s\n", hostnameStatus.Domainname)
 	}
 

diff --git a/internal/app/machined/pkg/controllers/network/etcfile_test.go b/internal/app/machined/pkg/controllers/network/etcfile_test.go
@@ -239,6 +239,24 @@ func (suite *EtcFileConfigSuite) TestNoExtraHosts() {
 	)
 }
 
+func (suite *EtcFileConfigSuite) TestNoSearchDomain() {
+	cfg := config.NewMachineConfig(
+		&v1alpha1.Config{
+			ConfigVersion: "v1alpha1",
+			MachineConfig: &v1alpha1.MachineConfig{
+				MachineNetwork: &v1alpha1.NetworkConfig{
+					NetworkDisableSearchDomain: true,
+				},
+			},
+		},
+	)
+	suite.testFiles(
+		[]resource.Resource{cfg, suite.defaultAddress, suite.hostnameStatus, suite.resolverStatus},
+		"nameserver 1.1.1.1\nnameserver 2.2.2.2\nnameserver 3.3.3.3\n",
+		"127.0.0.1       localhost\n33.11.22.44       foo.example.com foo\n::1             localhost ip6-localhost ip6-loopback\nff02::1         ip6-allnodes\nff02::2         ip6-allrouters", //nolint:lll
+	)
+}
+
 func (suite *EtcFileConfigSuite) TestNoDomainname() {
 	suite.hostnameStatus.TypedSpec().Domainname = ""
 

diff --git a/pkg/machinery/config/provider.go b/pkg/machinery/config/provider.go
@@ -141,6 +141,7 @@ type MachineNetwork interface {
 	Devices() []Device
 	ExtraHosts() []ExtraHost
 	KubeSpan() KubeSpan
+	DisableSearchDomain() bool
 }
 
 // ExtraHost represents a host entry in /etc/hosts.

diff --git a/pkg/machinery/config/types/v1alpha1/v1alpha1_provider.go b/pkg/machinery/config/types/v1alpha1/v1alpha1_provider.go
@@ -469,6 +469,11 @@ func (n *NetworkConfig) Hostname() string {
 	return n.NetworkHostname
 }
 
+// DisableSearchDomain implements the config.Provider interface.
+func (n *NetworkConfig) DisableSearchDomain() bool {
+	return n.NetworkDisableSearchDomain
+}
+
 // Devices implements the config.Provider interface.
 func (n *NetworkConfig) Devices() []config.Device {
 	interfaces := make([]config.Device, len(n.NetworkInterfaces))

diff --git a/pkg/machinery/config/types/v1alpha1/v1alpha1_types.go b/pkg/machinery/config/types/v1alpha1/v1alpha1_types.go
@@ -149,7 +149,8 @@ var (
 	kubeletImageExample = (&KubeletConfig{}).Image()
 
 	machineNetworkConfigExample = &NetworkConfig{
-		NetworkHostname: "worker-1",
+		NetworkHostname:            "worker-1",
+		NetworkDisableSearchDomain: false,
 		NetworkInterfaces: []*Device{
 			{
 				DeviceInterface: "eth0",
@@ -1061,6 +1062,16 @@ type NetworkConfig struct {
 	//   examples:
 	//     - value: networkKubeSpanExample
 	NetworkKubeSpan NetworkKubeSpan `yaml:"kubespan,omitempty"`
+	//   description: |
+	//     Disable generating a default search domain in /etc/resolv.conf
+	//     based on the machine hostname.
+	//     Defaults to `false`.
+	//   values:
+	//     - true
+	//     - yes
+	//     - false
+	//     - no
+	NetworkDisableSearchDomain bool `yaml:"disableSearchDomain,omitempty"`
 }
 
 // InstallConfig represents the installation options for preparing a node.

diff --git a/pkg/machinery/config/types/v1alpha1/v1alpha1_types_doc.go b/pkg/machinery/config/types/v1alpha1/v1alpha1_types_doc.go
diff --git a/website/content/v1.1/reference/configuration.md b/website/content/v1.1/reference/configuration.md
@@ -950,6 +950,7 @@ extraHostEntries:
 kubespan:
     enabled: true # Enable the KubeSpan feature.
 {{< /highlight >}}</details> | |
+|`disableSearchDomain` |bool |<details><summary>Disable generating a default search domain in /etc/resolv.conf</summary>based on the machine hostname.<br />Defaults to `false`.</details>  |`true`<br />`yes`<br />`false`<br />`no`<br /> |