Bug 1980866: [4.7] Prefer IPv6 hostIP on bootstrap IPv6 deployments

data/data/bootstrap/systemd/units/kubelet.service.template

@@ -18,6 +18,9 @@ ExecStart=/usr/bin/hyperkube \
     --container-runtime=remote \
     --container-runtime-endpoint=/var/run/crio/crio.sock \
     --runtime-request-timeout=${KUBELET_RUNTIME_REQUEST_TIMEOUT} \
+{{- if .UseIPv6ForNodeIP }}
+    --node-ip=:: \
+{{- end}}
     --pod-manifest-path=/etc/kubernetes/manifests \
     --minimum-container-ttl-duration=6m0s \
     --cluster-domain=cluster.local \

pkg/asset/ignition/bootstrap/bootstrap.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
+	"net"
 	"os"
 	"path"
 	"path/filepath"
@@ -59,6 +60,7 @@ type bootstrapTemplateData struct {
 	Registries            []sysregistriesv2.Registry
 	BootImage             string
 	PlatformData          platformTemplateData
+	UseIPv6ForNodeIP      bool
 }
 
 // platformTemplateData is the data to use to replace values in bootstrap
@@ -260,6 +262,14 @@ func (a *Bootstrap) getTemplateData(installConfig *types.InstallConfig, releaseI
 		platformData.VSphere = vsphere.GetTemplateData(installConfig.Platform.VSphere)
 	}
 
+	var APIIntVIPonIPv6 bool
+	platformAPIVIP := apiVIP(&installConfig.Platform)
+	if platformAPIVIP == "" {
+		APIIntVIPonIPv6 = false
+	} else {
+		APIIntVIPonIPv6 = net.ParseIP(platformAPIVIP).To4() == nil
+	}
+
 	// Set cluster profile
 	clusterProfile := ""
 	if cp := os.Getenv("OPENSHIFT_INSTALL_EXPERIMENTAL_CLUSTER_PROFILE"); cp != "" {
@@ -278,6 +288,7 @@ func (a *Bootstrap) getTemplateData(installConfig *types.InstallConfig, releaseI
 		BootImage:             string(*rhcosImage),
 		PlatformData:          platformData,
 		ClusterProfile:        clusterProfile,
+		UseIPv6ForNodeIP:      APIIntVIPonIPv6,
 	}, nil
 }
 
@@ -621,3 +632,24 @@ func warnIfCertificatesExpired(config *igntypes.Config) {
 		logrus.Warnf("Bootstrap Ignition-Config: %d certificates expired. Installation attempts with the created Ignition-Configs will possibly fail.", expiredCerts)
 	}
 }
+
+// APIVIP returns a string representation of the platform's API VIP
+// It returns an empty string if the platform does not configure a VIP
+func apiVIP(p *types.Platform) string {
+	switch {
+	case p == nil:
+		return ""
+	case p.BareMetal != nil:
+		return p.BareMetal.APIVIP
+	case p.OpenStack != nil:
+		return p.OpenStack.APIVIP
+	case p.VSphere != nil:
+		return p.VSphere.APIVIP
+	case p.Ovirt != nil:
+		return p.Ovirt.APIVIP
+	case p.Kubevirt != nil:
+		return p.Kubevirt.APIVIP
+	default:
+		return ""
+	}
+}