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feat(ipv6): add --disable-ipv6 flag for IPv4-only operation #142

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feat(ipv6): add --disable-ipv6 flag for IPv4-only operation #142

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7 changes: 6 additions & 1 deletion cmd/kubesolo/main.go
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Original file line number Diff line number Diff line change
Expand Up @@ -48,6 +48,7 @@ type kubesolo struct {
loadBalancer bool
localStorage bool
localStorageSharedPath string
disableIPv6 bool
embedded types.Embedded
}

Expand All @@ -74,6 +75,7 @@ func service() (*kubesolo, error) {
loadBalancer: *flags.LoadBalancer,
localStorage: *flags.LocalStorage,
localStorageSharedPath: *flags.LocalStorageSharedPath,
disableIPv6: *flags.DisableIPv6,
}, nil
}

Expand Down Expand Up @@ -207,7 +209,7 @@ func (s *kubesolo) run() {
}

log.Info().Str("component", "kubesolo").Msg("deploying coredns...")
if err := coredns.Deploy(s.embedded.AdminKubeconfigFile); err != nil {
if err := coredns.Deploy(s.embedded.AdminKubeconfigFile, s.embedded.DisableIPv6); err != nil {
log.Fatal().Err(err).Msg("failed to deploy coredns")
}

Expand Down Expand Up @@ -453,5 +455,8 @@ func (s *kubesolo) bootstrap() {

// Portainer Edge
IsPortainerEdge: s.portainerEdgeID != "" && s.portainerEdgeKey != "",

// IPv6
DisableIPv6: s.disableIPv6,
}
}
1 change: 1 addition & 0 deletions internal/config/flags/flags.go
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Expand Up @@ -25,4 +25,5 @@ var (
LocalStorageSharedPath = Application.Flag("local-storage-shared-path", "Path to the shared file system for the local storage. Defaults to empty string.").Envar("KUBESOLO_LOCAL_STORAGE_SHARED_PATH").Default("").String()
Debug = Application.Flag("debug", "Enable debug logging. Defaults to false.").Envar("KUBESOLO_DEBUG").Default("false").Bool()
PprofServer = Application.Flag("pprof-server", "Enable pprof server. Defaults to false.").Envar("KUBESOLO_PPROF_SERVER").Default("false").Bool()
DisableIPv6 = Application.Flag("disable-ipv6", "Disable IPv6 support. When set, CoreDNS will not serve ip6.arpa reverse zones and kubelet will register with an explicit IPv4 node address. Defaults to false.").Envar("KUBESOLO_DISABLE_IPV6").Default("false").Bool()
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Copilot AI Apr 28, 2026

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The flag help text says kubelet will only register with an explicit IPv4 node address when this flag is set, but the current kubelet args unconditionally set --node-ip. Either make kubelet’s --node-ip conditional on DisableIPv6, or adjust this description to match the actual behavior.

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)
32 changes: 28 additions & 4 deletions pkg/components/coredns/configuration.go
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Expand Up @@ -9,8 +9,25 @@ import (
"k8s.io/client-go/kubernetes"
)

// CoreDNSConfig contains minimal CoreDNS Corefile configuration
const CoreDNSConfig = `.:53 {
const coreDNSConfigIPv4Only = `.:53 {
errors
loop
cache 30 {
disable denial cluster.local
}
kubernetes cluster.local in-addr.arpa {
pods insecure
fallthrough in-addr.arpa
ttl 30
}
forward . /etc/resolv.conf
minimal
reload
health :8080
ready :8181
}`

const coreDNSConfigDualStack = `.:53 {
errors
loop
cache 30 {
Expand All @@ -28,18 +45,25 @@ const CoreDNSConfig = `.:53 {
ready :8181
}`

func coreDNSConfig(disableIPv6 bool) string {
if disableIPv6 {
return coreDNSConfigIPv4Only
}
return coreDNSConfigDualStack
}

// createConfigMap creates a configMap with the bare minimum CoreDNS configuration
// it creates a new configmap if it does not exist
// it updates the configmap if it already exists
// it returns an error if it fails
func createConfigMap(ctx context.Context, clientset *kubernetes.Clientset) error {
func createConfigMap(ctx context.Context, clientset *kubernetes.Clientset, disableIPv6 bool) error {
configMap := &corev1.ConfigMap{
ObjectMeta: metav1.ObjectMeta{
Name: coreDNSConfigMapName,
Namespace: coreDNSNamespace,
},
Data: map[string]string{
"Corefile": CoreDNSConfig,
"Corefile": coreDNSConfig(disableIPv6),
},
}

Expand Down
4 changes: 2 additions & 2 deletions pkg/components/coredns/coredns.go
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Expand Up @@ -22,7 +22,7 @@ const (
)

// Deploy deploys all the necessary Kubernetes resources for CoreDNS
func Deploy(adminKubeconfig string) error {
func Deploy(adminKubeconfig string, disableIPv6 bool) error {
time.Sleep(types.DefaultComponentSleep)

ctx, cancel := context.WithTimeout(context.Background(), types.DefaultContextTimeout)
Expand All @@ -33,7 +33,7 @@ func Deploy(adminKubeconfig string) error {
return fmt.Errorf("failed to create kubernetes client: %v", err)
}

if err := createConfigMap(ctx, clientset); err != nil {
if err := createConfigMap(ctx, clientset, disableIPv6); err != nil {
Comment on lines 24 to +36
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Copilot AI Apr 28, 2026

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Changing the exported coredns.Deploy signature to add a positional bool parameter is a breaking API change and the call site doesn’t self-document what true/false means. Consider using an options struct (e.g., Deploy(adminKubeconfig string, opts DeployOptions)) or a separate helper like DeployIPv4Only(...) to keep the API clearer and easier to extend without adding more boolean parameters.

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return fmt.Errorf("failed to create CoreDNS ConfigMap: %v", err)
}

Expand Down
1 change: 1 addition & 0 deletions pkg/kubernetes/kubelet/args.go
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Expand Up @@ -8,6 +8,7 @@ func (s *service) configureKubeletArgs(command *cobra.Command) {
command.SetArgs([]string{
"--config", s.kubeletConfigFile,
"--hostname-override", s.nodeName,
"--node-ip", s.nodeIP,
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Copilot AI Apr 28, 2026

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--node-ip is now always set. This changes kubelet behavior even when --disable-ipv6 is not enabled and will break IPv6-only hosts (it will force 127.0.0.1 from GetNodeIP() when no IPv4 exists). Consider only adding --node-ip when the new disable-IPv6 mode is enabled (e.g., plumb DisableIPv6 into the kubelet service) or otherwise allow kubelet to auto-select the appropriate node IP in dual-stack/IPv6 setups.

Suggested change
"--node-ip", s.nodeIP,

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"--root-dir", s.kubeletDir,
"--kubeconfig", s.kubeletKubeConfigFile,
})
Expand Down
3 changes: 3 additions & 0 deletions types/types.go
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Expand Up @@ -129,6 +129,9 @@ type Embedded struct {

// Portainer Edge
IsPortainerEdge bool

// IPv6
DisableIPv6 bool
}

// EdgeAgentConfig contains configuration for Portainer Edge Agent
Expand Down