Merge pull request kubernetes#86173 from soltysh/cli_defaults

stop defaulting kubeconfig to http://localhost:8080

Author: k8s-ci-robot

staging/src/k8s.io/cli-runtime/pkg/genericclioptions/config_flags.go

@@ -17,6 +17,7 @@ limitations under the License.
 package genericclioptions
 
 import (
+	"errors"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -55,7 +56,17 @@ const (
 	flagHTTPCacheDir     = "cache-dir"
 )
 
-var defaultCacheDir = filepath.Join(homedir.HomeDir(), ".kube", "http-cache")
+var (
+	defaultCacheDir = filepath.Join(homedir.HomeDir(), ".kube", "http-cache")
+
+	ErrEmptyConfig = errors.New(`Missing or incomplete configuration info.  Please point to an existing, complete config file:
+
+  1. Via the command-line flag --kubeconfig
+  2. Via the KUBECONFIG environment variable
+  3. In your home directory as ~/.kube/config
+
+To view or setup config directly use the 'config' command.`)
+)
 
 // RESTClientGetter is an interface that the ConfigFlags describe to provide an easier way to mock for commands
 // and eliminate the direct coupling to a struct type.  Users may wish to duplicate this type in their own packages
@@ -110,7 +121,12 @@ type ConfigFlags struct {
 // to a .kubeconfig file, loading rules, and config flag overrides.
 // Expects the AddFlags method to have been called.
 func (f *ConfigFlags) ToRESTConfig() (*rest.Config, error) {
-	return f.ToRawKubeConfigLoader().ClientConfig()
+	config, err := f.ToRawKubeConfigLoader().ClientConfig()
+	// replace client-go's ErrEmptyConfig error with our custom, more verbose version
+	if clientcmd.IsEmptyConfig(err) {
+		return nil, ErrEmptyConfig
+	}
+	return config, err
 }
 
 // ToRawKubeConfigLoader binds config flag values to config overrides

staging/src/k8s.io/client-go/tools/clientcmd/client_config.go

@@ -35,23 +35,14 @@ import (
 var (
 	// ClusterDefaults has the same behavior as the old EnvVar and DefaultCluster fields
 	// DEPRECATED will be replaced
-	ClusterDefaults = clientcmdapi.Cluster{Server: getDefaultServer()}
+	ClusterDefaults = clientcmdapi.Cluster{Server: os.Getenv("KUBERNETES_MASTER")}
 	// DefaultClientConfig represents the legacy behavior of this package for defaulting
 	// DEPRECATED will be replace
 	DefaultClientConfig = DirectClientConfig{*clientcmdapi.NewConfig(), "", &ConfigOverrides{
 		ClusterDefaults: ClusterDefaults,
 	}, nil, NewDefaultClientConfigLoadingRules(), promptedCredentials{}}
 )
 
-// getDefaultServer returns a default setting for DefaultClientConfig
-// DEPRECATED
-func getDefaultServer() string {
-	if server := os.Getenv("KUBERNETES_MASTER"); len(server) > 0 {
-		return server
-	}
-	return "http://localhost:8080"
-}
-
 // ClientConfig is used to make it easy to get an api server client
 type ClientConfig interface {
 	// RawConfig returns the merged result of all overrides

staging/src/k8s.io/client-go/tools/clientcmd/validation.go

@@ -30,7 +30,7 @@ import (
 
 var (
 	ErrNoContext   = errors.New("no context chosen")
-	ErrEmptyConfig = errors.New("no configuration has been provided")
+	ErrEmptyConfig = errors.New("no configuration has been provided, try setting KUBERNETES_MASTER environment variable")
 	// message is for consistency with old behavior
 	ErrEmptyCluster = errors.New("cluster has no server defined")
 )

test/cmd/legacy-script.sh

@@ -325,6 +325,7 @@ runTests() {
     exit 1
   fi
   kube::log::status "Checking kubectl version"
+  export KUBERNETES_MASTER=http://127.0.0.1:${API_PORT}
   kubectl version
 
   # Generate a random namespace name, based on the current time (to make