Merge pull request #2173 from aojea/dual_followup

Dual stack follow-ups
kubernetes-sigs · Apr 1, 2021 · bbede40 · bbede40
2 parents 8fe8b96 + 31e5956
commit bbede40
Show file tree

Hide file tree

Showing 4 changed files with 62 additions and 61 deletions.
diff --git a/pkg/cluster/internal/create/actions/config/config.go b/pkg/cluster/internal/create/actions/config/config.go
@@ -78,7 +78,7 @@ func (a *Action) Execute(ctx *actions.ActionContext) error {
 		KubeProxyMode:        string(ctx.Config.Networking.KubeProxyMode),
 		ServiceSubnet:        ctx.Config.Networking.ServiceSubnet,
 		ControlPlane:         true,
-		IPv6:                 ctx.Config.Networking.IPFamily == config.IPv6Family,
+		IPFamily:             ctx.Config.Networking.IPFamily,
 		FeatureGates:         ctx.Config.FeatureGates,
 		RuntimeConfig:        ctx.Config.RuntimeConfig,
 		RootlessProvider:     providerInfo.Rootless,

diff --git a/pkg/cluster/internal/kubeadm/config.go b/pkg/cluster/internal/kubeadm/config.go
@@ -25,6 +25,7 @@ import (
 
 	"k8s.io/apimachinery/pkg/util/version"
 	"sigs.k8s.io/kind/pkg/errors"
+	"sigs.k8s.io/kind/pkg/internal/apis/config"
 )
 
 // ConfigData is supplied to the kubeadm config template, with values populated
@@ -67,8 +68,8 @@ type ConfigData struct {
 	// Kubernetes API Server RuntimeConfig
 	RuntimeConfig map[string]string
 
-	// IPv4 values take precedence over IPv6 by default, if true set IPv6 default values
-	IPv6 bool
+	// IPFamily of the cluster, it can be IPv4, IPv6 or DualStack
+	IPFamily config.ClusterIPFamily
 
 	// Labels are the labels, in the format "key1=val1,key2=val2", with which the respective node will be labeled
 	NodeLabels string
@@ -96,6 +97,10 @@ type DerivedConfigData struct {
 	FeatureGatesString string
 	// RuntimeConfigString is of the form `Foo=true,Baz=false`
 	RuntimeConfigString string
+	// KubeadmFeatureGates contains Kubeadm only feature gates
+	KubeadmFeatureGates map[string]bool
+	// IPv4 values take precedence over IPv6 by default, if true set IPv6 default values
+	IPv6 bool
 }
 
 // Derive automatically derives DockerStableTag if not specified
@@ -107,6 +112,9 @@ func (c *ConfigData) Derive() {
 		c.DockerStableTag = strings.Replace(c.KubernetesVersion, "+", "_", -1)
 	}
 
+	// get the IP addresses family for defaulting components
+	c.IPv6 = c.IPFamily == config.IPv6Family
+
 	// get sorted list of FeatureGate keys
 	featureGateKeys := make([]string, 0, len(c.FeatureGates))
 	for k := range c.FeatureGates {
@@ -281,6 +289,10 @@ metadata:
   name: config
 kubernetesVersion: {{.KubernetesVersion}}
 clusterName: "{{.ClusterName}}"
+{{ if .KubeadmFeatureGates}}featureGates:
+{{ range $key, $value := .KubeadmFeatureGates }}
+  "{{ $key }}": {{ $value }}
+{{end}}{{end}}
 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
@@ -439,6 +451,17 @@ func Config(data ConfigData) (config string, err error) {
 	// derive any automatic fields if not supplied
 	data.Derive()
 
+	// Kubeadm has its own feature-gate for dual stack
+	// we need to enable it for Kubernetes version 1.20 only
+	// dual-stack is only supported in 1.20+
+	// TODO: remove this when 1.20 is EOL or we no longer support
+	// dual-stack for 1.20 in KIND
+	if ver.LessThan(version.MustParseSemantic("v1.21.0")) &&
+		ver.AtLeast(version.MustParseSemantic("v1.20.0")) {
+		data.KubeadmFeatureGates = make(map[string]bool)
+		data.KubeadmFeatureGates["IPv6DualStack"] = true
+	}
+
 	// execute the template
 	var buff bytes.Buffer
 	err = t.Execute(&buff, data)

diff --git a/site/content/docs/user/configuration.md b/site/content/docs/user/configuration.md
@@ -102,22 +102,52 @@ Multiple details of the cluster's networking can be customized under the
 
 #### IP Family
 
-KIND has limited support for IPv6 (and soon dual-stack!) clusters, you can switch
-from the default of IPv4 by setting:
+KIND has support for IPv4, IPv6 and dual-stack clusters, you can switch from the default of IPv4 by setting:
 
+##### IPv6 clusters
+You can run IPv6 single-stack clusters using `kind`, if the host that runs the docker containers support IPv6.
+Most operating systems / distros have IPv6 enabled by default, but you can check on Linux with the following command:
+
+```sh
+sudo sysctl net.ipv6.conf.all.disable_ipv6
+```
+
+You should see:
+
+```sh
+net.ipv6.conf.all.disable_ipv6 = 0
+```
+
+If you are using Docker on Windows or Mac, you will need to use an IPv4 port
+forward for the API Server from the host because IPv6 port forwards don't work
+on these platforms, you can do this with the following config:
 
 {{< codeFromInline lang="yaml" >}}
 kind: Cluster
 apiVersion: kind.x-k8s.io/v1alpha4
 networking:
   ipFamily: ipv6
+  apiServerAddress: 127.0.0.1
 {{< /codeFromInline >}}
 
-NOTE: you may need to [reconfigure your docker daemon](https://docs.docker.com/config/daemon/ipv6/) 
-to enable ipv6 in order to use this. 
+On Linux all you need is:
 
-IPv6 does not work on docker for mac because port forwarding ipv6
-is not yet supported in docker for mac.
+{{< codeFromInline lang="yaml" >}}
+kind: Cluster
+apiVersion: kind.x-k8s.io/v1alpha4
+networking:
+  ipFamily: ipv6
+{{< /codeFromInline >}}
+
+##### Dual Stack clusters
+You can run dual stack clusters using `kind` 0.11+, on kubernetes versions 1.20+.
+
+{{< codeFromInline lang="yaml" >}}
+kind: Cluster
+apiVersion: kind.x-k8s.io/v1alpha4
+networking:
+  ipFamily: dual
+{{< /codeFromInline >}}
 
 #### API Server
 

diff --git a/site/content/docs/user/quick-start.md b/site/content/docs/user/quick-start.md
@@ -334,58 +334,6 @@ featureGates:
   FeatureGateName: true
 {{< /codeFromInline >}}
 
-#### IPv6 clusters
-You can run IPv6 single-stack clusters using `kind`, if the host that runs the docker containers support IPv6.
-Most operating systems / distros have IPv6 enabled by default, but you can check on Linux with the following command:
-
-```sh
-sudo sysctl net.ipv6.conf.all.disable_ipv6
-```
-
-You should see:
-
-```sh
-net.ipv6.conf.all.disable_ipv6 = 0
-```
-
-If you are using Docker on Windows or Mac, you will need to use an IPv4 port
-forward for the API Server from the host because IPv6 port forwards don't work
-on these platforms, you can do this with the following config:
-
-```yaml
-# an ipv6 cluster
-kind: Cluster
-apiVersion: kind.x-k8s.io/v1alpha4
-networking:
-  ipFamily: ipv6
-  apiServerAddress: 127.0.0.1
-```
-
-On Linux all you need is:
-```yaml
-# an ipv6 cluster
-kind: Cluster
-apiVersion: kind.x-k8s.io/v1alpha4
-networking:
-  ipFamily: ipv6
-```
-
-#### Dual Stack clusters
-You can run dual stack clusters using `kind`, on kubernetes versions +1.21
-but first you need to [enable ipv6 in your docker daemon][docker enable ipv6].
-
-```yaml
-# a dual-stack cluster
-kind: Cluster
-apiVersion: kind.x-k8s.io/v1alpha4
-networking:
-  ipFamily: dual
-nodes:
-- role: control-plane
-- role: worker
-- role: worker
-```
-
 ### Configure kind to use a proxy
 If you are running kind in an environment that requires a proxy, you may need to configure kind to use it.