From 4452848ffa0bda0c697d1063c1f649addf593f57 Mon Sep 17 00:00:00 2001
From: Antonio Ojea <antonio.ojea.garcia@gmail.com>
Date: Fri, 20 Dec 2019 15:43:05 +0100
Subject: [PATCH] kubelet and apiserver autodetect ipv6 address

use `::` as argument to autodetect the IPv6 adderss
bind apiserver to ipv6 address
kubelet autodetect node ip
---
 .../internal/create/actions/config/config.go  |   1 +
 pkg/cluster/internal/kubeadm/config.go        | 111 +++++++++++++++++-
 2 files changed, 111 insertions(+), 1 deletion(-)

diff --git a/pkg/cluster/internal/create/actions/config/config.go b/pkg/cluster/internal/create/actions/config/config.go
index d92f0c4dc4..d1ebda9d84 100644
--- a/pkg/cluster/internal/create/actions/config/config.go
+++ b/pkg/cluster/internal/create/actions/config/config.go
@@ -200,6 +200,7 @@ func getKubeadmConfig(cfg *config.Cluster, data kubeadm.ConfigData, node nodes.N
 		return "", errors.Wrap(err, "failed to get IP for node")
 	}
 
+	// TODO: this is no longer needed since v1.18
 	data.NodeAddress = nodeAddress
 	// configure the right protocol addresses
 	if cfg.Networking.IPFamily == "ipv6" {
diff --git a/pkg/cluster/internal/kubeadm/config.go b/pkg/cluster/internal/kubeadm/config.go
index eaa9a128ab..4b4c4eb25e 100644
--- a/pkg/cluster/internal/kubeadm/config.go
+++ b/pkg/cluster/internal/kubeadm/config.go
@@ -509,6 +509,113 @@ metadata:
 {{end}}{{end}}
 `
 
+// ConfigTemplateV118BetaV2 is the kubadm config template for API version v1beta2 and k8s > v1.18
+const ConfigTemplateV118BetaV2 = `# config generated by kind
+apiVersion: kubeadm.k8s.io/v1beta2
+kind: ClusterConfiguration
+metadata:
+  name: config
+kubernetesVersion: {{.KubernetesVersion}}
+clusterName: "{{.ClusterName}}"
+controlPlaneEndpoint: "{{ .ControlPlaneEndpoint }}"
+# on docker for mac we have to expose the api server via port forward,
+# so we need to ensure the cert is valid for localhost so we can talk
+# to the cluster after rewriting the kubeconfig to point to localhost
+apiServer:
+  certSANs: [localhost, "{{.APIServerAddress}}"]
+  extraArgs:
+    {{ if .IPv6 -}}
+    bind-address: "::"
+    {{- end }}
+controllerManager:
+  extraArgs:
+    enable-hostpath-provisioner: "true"
+    # configure ipv6 default addresses for IPv6 clusters
+    {{ if .IPv6 -}}
+    bind-address: "::1"
+    {{- end }}
+scheduler:
+  extraArgs:
+    # configure ipv6 default addresses for IPv6 clusters
+    {{ if .IPv6 -}}
+    bind-address: "::1"
+    {{- end }}
+networking:
+  podSubnet: "{{ .PodSubnet }}"
+  serviceSubnet: "{{ .ServiceSubnet }}"
+---
+apiVersion: kubeadm.k8s.io/v1beta2
+kind: InitConfiguration
+metadata:
+  name: config
+# we use a well know token for TLS bootstrap
+bootstrapTokens:
+- token: "{{ .Token }}"
+# we use a well know port for making the API server discoverable inside docker network.
+# from the host machine such port will be accessible via a random local port instead.
+localAPIEndpoint:
+  {{ if .IPv6 -}}
+  advertiseAddress: "::"
+  {{- end }}
+  bindPort: {{.APIBindPort}}
+nodeRegistration:
+  criSocket: "/run/containerd/containerd.sock"
+  kubeletExtraArgs:
+    fail-swap-on: "false"
+    {{ if .IPv6 -}}
+    node-ip: "::"
+    {{- end }}
+---
+apiVersion: kubeadm.k8s.io/v1beta2
+kind: JoinConfiguration
+metadata:
+  name: config
+{{ if .ControlPlane -}}
+controlPlane:
+  localAPIEndpoint:
+    {{ if .IPv6 -}}
+    advertiseAddress: "::"
+    {{- end }}
+    bindPort: {{.APIBindPort}}
+{{- end }}
+nodeRegistration:
+  criSocket: "/run/containerd/containerd.sock"
+  kubeletExtraArgs:
+    fail-swap-on: "false"
+    {{ if .IPv6 -}}
+    node-ip: "::"
+    {{- end }}
+discovery:
+  bootstrapToken:
+    apiServerEndpoint: "{{ .ControlPlaneEndpoint }}"
+    token: "{{ .Token }}"
+    unsafeSkipCAVerification: true
+---
+apiVersion: kubelet.config.k8s.io/v1beta1
+kind: KubeletConfiguration
+metadata:
+  name: config
+# configure ipv6 addresses in IPv6 mode
+{{ if .IPv6 -}}
+address: "::"
+healthzBindAddress: "::"
+{{- end }}
+# disable disk resource management by default
+# kubelet will see the host disk that the inner container runtime
+# is ultimately backed by and attempt to recover disk space. we don't want that.
+imageGCHighThresholdPercent: 100
+evictionHard:
+  nodefs.available: "0%"
+  nodefs.inodesFree: "0%"
+  imagefs.available: "0%"
+---
+# no-op entry that exists solely so it can be patched
+apiVersion: kubeproxy.config.k8s.io/v1alpha1
+kind: KubeProxyConfiguration
+metadata:
+  name: config
+`
+
 // Config returns a kubeadm config generated from config data, in particular
 // the kubernetes version
 func Config(data ConfigData) (config string, err error) {
@@ -518,7 +625,7 @@ func Config(data ConfigData) (config string, err error) {
 	}
 
 	// assume the latest API version, then fallback if the k8s version is too low
-	templateSource := ConfigTemplateBetaV2
+	templateSource := ConfigTemplateV118BetaV2
 	if ver.LessThan(version.MustParseSemantic("v1.12.0")) {
 		// in Kubernetes 1.11 we need to enable this feature, unless the user
 		// explicitly disabled it. this is considered part of our "base config"
@@ -532,6 +639,8 @@ func Config(data ConfigData) (config string, err error) {
 		templateSource = ConfigTemplateAlphaV3
 	} else if ver.LessThan(version.MustParseSemantic("v1.15.0")) {
 		templateSource = ConfigTemplateBetaV1
+	} else if ver.LessThan(version.MustParseSemantic("v1.18.0")) {
+		templateSource = ConfigTemplateBetaV2
 	}
 
 	t, err := template.New("kubeadm-config").Parse(templateSource)