From b0aa2c718ccad1b03a16c8b86de8cb9ae4ae0603 Mon Sep 17 00:00:00 2001
From: Roberto Bonafiglia <roberto.bonafiglia@suse.com>
Date: Tue, 10 Oct 2023 12:34:54 +0200
Subject: [PATCH] Use IPv6 in case is the first configured IP with dualstack

Signed-off-by: Roberto Bonafiglia <roberto.bonafiglia@suse.com>
---
 pkg/agent/config/config.go       |  2 +-
 pkg/agent/run.go                 |  2 +-
 pkg/daemons/agent/agent_linux.go | 19 +++++++++++--------
 3 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/pkg/agent/config/config.go b/pkg/agent/config/config.go
index b3f107324d24..62eb616d4857 100644
--- a/pkg/agent/config/config.go
+++ b/pkg/agent/config/config.go
@@ -353,7 +353,7 @@ func get(ctx context.Context, envInfo *cmds.Agent, proxy proxy.Proxy) (*config.N
 
 	// If the supervisor and externally-facing apiserver are not on the same port, tell the proxy where to find the apiserver.
 	if controlConfig.SupervisorPort != controlConfig.HTTPSPort {
-		_, isIPv6, _ := util.GetFirstString([]string{envInfo.NodeIP.String()})
+		isIPv6 := utilsnet.IsIPv6(net.ParseIP([]string{envInfo.NodeIP.String()}[0]))
 		if err := proxy.SetAPIServerPort(ctx, controlConfig.HTTPSPort, isIPv6); err != nil {
 			return nil, errors.Wrapf(err, "failed to setup access to API Server port %d on at %s", controlConfig.HTTPSPort, proxy.SupervisorURL())
 		}
diff --git a/pkg/agent/run.go b/pkg/agent/run.go
index 58fd2ed52e3a..7b8a9c6ade6e 100644
--- a/pkg/agent/run.go
+++ b/pkg/agent/run.go
@@ -277,7 +277,7 @@ func createProxyAndValidateToken(ctx context.Context, cfg *cmds.Agent) (proxy.Pr
 	if err := os.MkdirAll(agentDir, 0700); err != nil {
 		return nil, err
 	}
-	_, isIPv6, _ := util.GetFirstString([]string{cfg.NodeIP.String()})
+	isIPv6 := utilsnet.IsIPv6(net.ParseIP([]string{cfg.NodeIP.String()}[0]))
 
 	proxy, err := proxy.NewSupervisorProxy(ctx, !cfg.DisableLoadBalancer, agentDir, cfg.ServerURL, cfg.LBServerPort, isIPv6)
 	if err != nil {
diff --git a/pkg/daemons/agent/agent_linux.go b/pkg/daemons/agent/agent_linux.go
index ead7507aee73..06df2106449d 100644
--- a/pkg/daemons/agent/agent_linux.go
+++ b/pkg/daemons/agent/agent_linux.go
@@ -4,6 +4,7 @@
 package agent
 
 import (
+	"net"
 	"os"
 	"path/filepath"
 	"strings"
@@ -13,8 +14,8 @@ import (
 	"github.com/k3s-io/k3s/pkg/util"
 	"github.com/sirupsen/logrus"
 	"golang.org/x/sys/unix"
-	"k8s.io/apimachinery/pkg/util/net"
 	"k8s.io/kubernetes/pkg/kubeapiserver/authorizer/modes"
+	utilsnet "k8s.io/utils/net"
 )
 
 const socketPrefix = "unix://"
@@ -32,8 +33,8 @@ func createRootlessConfig(argsMap map[string]string, controllers map[string]bool
 
 func kubeProxyArgs(cfg *config.Agent) map[string]string {
 	bindAddress := "127.0.0.1"
-	_, IPv6only, _ := util.GetFirstString([]string{cfg.NodeIP})
-	if IPv6only {
+	isIPv6 := utilsnet.IsIPv6(net.ParseIP([]string{cfg.NodeIP}[0]))
+	if isIPv6 {
 		bindAddress = "::1"
 	}
 	argsMap := map[string]string{
@@ -53,8 +54,8 @@ func kubeProxyArgs(cfg *config.Agent) map[string]string {
 
 func kubeletArgs(cfg *config.Agent) map[string]string {
 	bindAddress := "127.0.0.1"
-	_, IPv6only, _ := util.GetFirstString([]string{cfg.NodeIP})
-	if IPv6only {
+	isIPv6 := utilsnet.IsIPv6(net.ParseIP([]string{cfg.NodeIP}[0]))
+	if isIPv6 {
 		bindAddress = "::1"
 	}
 	argsMap := map[string]string{
@@ -122,9 +123,11 @@ func kubeletArgs(cfg *config.Agent) map[string]string {
 	if cfg.NodeName != "" {
 		argsMap["hostname-override"] = cfg.NodeName
 	}
-	defaultIP, err := net.ChooseHostInterface()
-	if err != nil || defaultIP.String() != cfg.NodeIP {
-		argsMap["node-ip"] = cfg.NodeIP
+	if nodeIPs := util.JoinIPs(cfg.NodeIPs); nodeIPs != "" {
+		dualStack, err := utilsnet.IsDualStackIPs(cfg.NodeIPs)
+		if err == nil && !dualStack {
+			argsMap["node-ip"] = cfg.NodeIP
+		}
 	}
 	kubeletRoot, runtimeRoot, controllers := cgroups.CheckCgroups()
 	if !controllers["cpu"] {