Fix: Change DefaultAPIHost from 0.0.0.0 to 127.0.0.1

pkg/client/cluster.go

@@ -386,7 +386,7 @@ ClusterCreatOpts:
 	/*
 	 * Docker Machine Special Configuration
 	 */
-	if cluster.KubeAPI.Host == k3d.DefaultAPIHost && runtime == k3drt.Docker {
+	if (cluster.KubeAPI.Host == k3d.DefaultAPIHost || cluster.KubeAPI.Host == "0.0.0.0") && runtime == k3drt.Docker {
 		// If the runtime is docker, attempt to use the docker host
 		if runtime == k3drt.Docker {
 			dockerHost := runtime.GetHost()

pkg/client/kubeconfig_test.go

@@ -0,0 +1,38 @@
+/*
+Copyright © 2020-2023 The k3d Author(s)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+
+package client
+
+import (
+	"testing"
+
+	k3d "github.com/k3d-io/k3d/v5/pkg/types"
+)
+
+func TestDefaultAPIHostIsLoopback(t *testing.T) {
+	// Verify that DefaultAPIHost is set to 127.0.0.1 (loopback) instead of 0.0.0.0
+	// This ensures that kubeconfig files use a valid client-connectable address
+	expectedHost := "127.0.0.1"
+	if k3d.DefaultAPIHost != expectedHost {
+		t.Errorf("DefaultAPIHost should be '%s' for client connectivity, but got '%s'", expectedHost, k3d.DefaultAPIHost)
+	}
+}

pkg/client/registry.go

@@ -312,7 +312,7 @@ func RegistryGenerateLocalRegistryHostingConfigMapYAML(ctx context.Context, runt
 	}
 
 	// if the host is now 0.0.0.0, check if we can set it to the IP of the docker-machine, if it's used
-	if host == k3d.DefaultAPIHost && runtime == runtimes.Docker {
+	if (host == k3d.DefaultAPIHost || host == "0.0.0.0") && runtime == runtimes.Docker {
 		if gort.GOOS == "windows" || gort.GOOS == "darwin" {
 			l.Log().Tracef("Running on %s: checking if it's using docker-machine", gort.GOOS)
 			machineIP, err := runtime.(docker.Docker).GetDockerMachineIP()
@@ -328,7 +328,7 @@ func RegistryGenerateLocalRegistryHostingConfigMapYAML(ctx context.Context, runt
 	}
 
 	// if host is still 0.0.0.0, use localhost instead
-	if host == k3d.DefaultAPIHost {
+	if host == k3d.DefaultAPIHost || host == "0.0.0.0" {
 		host = "localhost" // we prefer localhost over 0.0.0.0
 	}
 

pkg/types/defaults.go

@@ -83,7 +83,7 @@ const DefaultKubeconfigPrefix = DefaultObjectNamePrefix + "-kubeconfig"
 const DefaultAPIPort = "6443"
 
 // DefaultAPIHost defines the default host (IP) for the Kubernetes API
-const DefaultAPIHost = "0.0.0.0"
+const DefaultAPIHost = "127.0.0.1"
 
 // GetDefaultObjectName prefixes the passed name with the default prefix
 func GetDefaultObjectName(name string) string {