Resolve clusterDNS for IPv6 MNG AL2023 with custom AMI (#8170)

* resolve cluster DNS for IPv6 MNG AL2023 with custom AMI

* correct error message

Author: TiberiuGC

pkg/nodebootstrap/al2023_test.go

@@ -33,10 +33,6 @@ var _ = DescribeTable("Unmanaged AL2023", func(e al2023Entry) {
 	ng := api.NewNodeGroup()
 	makeDefaultNPSettings(ng)
 
-	if e.overrideClusterSettings != nil {
-		e.overrideClusterSettings(cfg)
-	}
-
 	if e.overrideNodegroupSettings != nil {
 		e.overrideNodegroupSettings(ng)
 	}
@@ -54,14 +50,6 @@ var _ = DescribeTable("Unmanaged AL2023", func(e al2023Entry) {
 	Entry("default", al2023Entry{
 		expectedUserData: wrapMIMEParts(nodeConfig),
 	}),
-	Entry("ipv6", al2023Entry{
-		overrideClusterSettings: func(cc *api.ClusterConfig) {
-			cc.Status.KubernetesNetworkConfig.IPFamily = api.IPV6Family
-			cc.Status.KubernetesNetworkConfig.ServiceIPv6CIDR = "fd00:facc:76a1::/108"
-			cc.Status.KubernetesNetworkConfig.ServiceIPv4CIDR = ""
-		},
-		expectedUserData: wrapMIMEParts(nodeConfigIPv6),
-	}),
 	Entry("efa enabled", al2023Entry{
 		overrideNodegroupSettings: func(np api.NodePool) {
 			np.BaseNodeGroup().EFAEnabled = aws.Bool(true)
@@ -71,7 +59,13 @@ var _ = DescribeTable("Unmanaged AL2023", func(e al2023Entry) {
 )
 
 var _ = DescribeTable("Managed AL2023", func(e al2023Entry) {
-	cfg, dns := makeDefaultClusterSettings()
+	cfg, _ := makeDefaultClusterSettings()
+	if e.overrideClusterSettings != nil {
+		e.overrideClusterSettings(cfg)
+	}
+	dns, err := nodebootstrap.GetClusterDNS(cfg)
+	Expect(err).NotTo(HaveOccurred())
+
 	mng := api.NewManagedNodeGroup()
 	makeDefaultNPSettings(mng)
 	mng.Taints = append(mng.Taints, api.NodeGroupTaint{
@@ -101,6 +95,17 @@ var _ = DescribeTable("Managed AL2023", func(e al2023Entry) {
 		},
 		expectedUserData: wrapMIMEParts(managedNodeConfig),
 	}),
+	Entry("custom AMI IPv6", al2023Entry{
+		overrideClusterSettings: func(cc *api.ClusterConfig) {
+			cc.Status.KubernetesNetworkConfig.IPFamily = api.IPV6Family
+			cc.Status.KubernetesNetworkConfig.ServiceIPv6CIDR = "fd40:6404:f93b::/108"
+			cc.Status.KubernetesNetworkConfig.ServiceIPv4CIDR = ""
+		},
+		overrideNodegroupSettings: func(np api.NodePool) {
+			np.BaseNodeGroup().AMI = "ami-xxxx"
+		},
+		expectedUserData: wrapMIMEParts(managedNodeConfigIPv6),
+	}),
 )
 
 type al2023OverrideNodeConfigEntry struct {
@@ -400,7 +405,7 @@ spec:
     - --node-labels=alpha.eksctl.io/nodegroup-name=al2023-mng-test
 
 `
-	nodeConfigIPv6 = `--//
+	managedNodeConfigIPv6 = `--//
 Content-Type: application/node.eks.aws
 
 apiVersion: node.eks.aws/v1alpha1
@@ -411,17 +416,18 @@ spec:
   cluster:
     apiServerEndpoint: https://test.xxx.us-west-2.eks.amazonaws.com
     certificateAuthority: dGVzdCBDQQ==
-    cidr: fd00:facc:76a1::/108
+    cidr: fd40:6404:f93b::/108
     name: al2023-test
   containerd: {}
   instance:
     localStorage: {}
   kubelet:
     config:
       clusterDNS:
-      - 10.100.0.10
+      - fd40:6404:f93b::a
     flags:
     - --node-labels=alpha.eksctl.io/nodegroup-name=al2023-mng-test
+    - --register-with-taints=special=true:NoSchedule
 
 `
 	managedNodeConfig = `--//

pkg/nodebootstrap/userdata.go

@@ -89,17 +89,37 @@ func NewManagedBootstrapper(clusterConfig *api.ClusterConfig, ng *api.ManagedNod
 // GetClusterDNS returns the DNS address to use
 func GetClusterDNS(clusterConfig *api.ClusterConfig) (string, error) {
 	networkConfig := clusterConfig.Status.KubernetesNetworkConfig
-	if networkConfig == nil || networkConfig.ServiceIPv4CIDR == "" {
+	if networkConfig == nil {
 		return "", nil
 	}
 
-	ip, _, err := net.ParseCIDR(networkConfig.ServiceIPv4CIDR)
+	var (
+		serviceCIDR  string
+		toClusterDNS func(net.IP) string
+	)
+
+	if networkConfig.ServiceIPv4CIDR != "" {
+		serviceCIDR = networkConfig.ServiceIPv4CIDR
+		toClusterDNS = func(parsedIP net.IP) string {
+			ip := parsedIP.To4()
+			ip[net.IPv4len-1] = 10
+			return ip.String()
+		}
+	}
+	if networkConfig.ServiceIPv6CIDR != "" {
+		serviceCIDR = networkConfig.ServiceIPv6CIDR
+		toClusterDNS = func(parsedIP net.IP) string {
+			ip := parsedIP.To16()
+			ip[net.IPv6len-1] = 10
+			return ip.String()
+		}
+	}
+
+	parsedIP, _, err := net.ParseCIDR(serviceCIDR)
 	if err != nil {
-		return "", errors.Wrapf(err, "unexpected error parsing kubernetesNetworkConfig.serviceIPv4CIDR: %q", networkConfig.ServiceIPv4CIDR)
+		return "", errors.Wrapf(err, "unexpected error parsing KubernetesNetworkConfig service CIDR: %q", serviceCIDR)
 	}
-	ip = ip.To4()
-	ip[net.IPv4len-1] = 10
-	return ip.String(), nil
+	return toClusterDNS(parsedIP), nil
 }
 
 func linuxConfig(clusterConfig *api.ClusterConfig, bootScriptName, bootScriptContent, clusterDNS string, np api.NodePool, scripts ...script) (string, error) {