Merge pull request #527 from jnummelin/external-api-address

Config option for external api address

cmd/server.go

@@ -27,6 +27,7 @@ import (
 	"github.com/spf13/cobra"
 
 	"github.com/k0sproject/k0s/pkg/build"
+	"github.com/k0sproject/k0s/pkg/kubernetes"
 	"github.com/k0sproject/k0s/pkg/telemetry"
 
 	"github.com/avast/retry-go"
@@ -200,6 +201,23 @@ func startServer(token string) error {
 		})
 	}
 
+	// common factory to get the admin kube client that's needed in many components
+	// TODO: Refactor all needed components to use this factory
+	adminClientFactory := kubernetes.NewAdminClientFactory(k0sVars)
+
+	// One leader elector per controller
+	// TODO: Make all other needed components use this "global" leader elector
+	leaderElector := server.NewLeaderElector(clusterConfig, adminClientFactory)
+	componentManager.Add(leaderElector)
+
+	if clusterConfig.Spec.API.ExternalAddress != "" {
+		componentManager.Add(server.NewEndpointReconciler(
+			clusterConfig,
+			leaderElector,
+			adminClientFactory,
+		))
+	}
+
 	perfTimer.Checkpoint("starting-component-init")
 	// init components
 	if err := componentManager.Init(); err != nil {

docs/configuration.md

@@ -66,10 +66,10 @@ metadata:
   name: k0s
 spec:
   api:
+    externalAddress: my-lb-address.example.com
     address: 192.168.68.106
     sans:
     - 192.168.68.106
-    - 192.168.68.106
     extraArgs: {}
   controllerManager:
     extraArgs: {}
@@ -143,6 +143,7 @@ extensions:
 
 ### `spec.api`
 
+- `externalAddress`: If k0s controllers are running behind a loadbalancer provide the loadbalancer address here. This will configure all cluster components to connect to this address and also configures this address to be used when joining new nodes into the cluster.
 - `address`: The local address to bind API on. Also used as one of the addresses pushed on the k0s create service certificate on the API. Defaults to first non-local address found on the node.
 - `sans`: List of additional addresses to push to API servers serving certificate
 - `extraArgs`: Map of key-values (strings) for any extra arguments you wish to pass down to Kubernetes api-server process

internal/util/slice.go

@@ -40,3 +40,16 @@ func IsStringArrayEqual(a1 []string, a2 []string) bool {
 	}
 	return false
 }
+
+// Unique returns only the unique items from given input slice
+func Unique(input []string) []string {
+	m := make(map[string]bool)
+	result := make([]string, 0, len(input))
+	for _, s := range input {
+		if _, ok := m[s]; !ok {
+			m[s] = true
+			result = append(result, s)
+		}
+	}
+	return result
+}

internal/util/slice_test.go

@@ -15,7 +15,11 @@ limitations under the License.
 */
 package util
 
-import "testing"
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
 
 func TestStringSliceContains(t *testing.T) {
 	type args struct {
@@ -88,3 +92,31 @@ func TestArrayIsEqual(t *testing.T) {
 		})
 	}
 }
+
+func TestUnique(t *testing.T) {
+	tests := []struct {
+		name  string
+		input []string
+		want  []string
+	}{
+		{
+			"all unique",
+			[]string{"a", "b", "c"},
+			[]string{"a", "b", "c"},
+		},
+		{
+			"some non unique",
+			[]string{"c", "a", "b", "b", "c"},
+			[]string{"c", "a", "b"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := Unique(tt.input)
+			assert.Equal(t, tt.want, got)
+
+		})
+	}
+
+}

pkg/apis/v1beta1/cluster.go

@@ -55,9 +55,10 @@ type ClusterSpec struct {
 
 // APISpec ...
 type APISpec struct {
-	Address   string            `yaml:"address"`
-	SANs      []string          `yaml:"sans"`
-	ExtraArgs map[string]string `yaml:"extraArgs"`
+	Address         string            `yaml:"address"`
+	ExternalAddress string            `yaml:"externalAddress"`
+	SANs            []string          `yaml:"sans"`
+	ExtraArgs       map[string]string `yaml:"extraArgs"`
 }
 
 // ControllerManagerSpec ...
@@ -88,14 +89,32 @@ func (c *ClusterConfig) Validate() []error {
 
 // APIAddress ...
 func (a *APISpec) APIAddress() string {
+	if a.ExternalAddress != "" {
+		return fmt.Sprintf("https://%s:6443", a.ExternalAddress)
+	}
 	return fmt.Sprintf("https://%s:6443", a.Address)
 }
 
 // K0sControlPlaneAPIAddress returns the controller join APIs address
 func (a *APISpec) K0sControlPlaneAPIAddress() string {
+	if a.ExternalAddress != "" {
+		return fmt.Sprintf("https://%s:9443", a.ExternalAddress)
+	}
 	return fmt.Sprintf("https://%s:9443", a.Address)
 }
 
+// Sans return the given SANS plus all local adresses and externalAddress if given
+func (a *APISpec) Sans() []string {
+	sans, _ := util.AllAddresses()
+	sans = append(sans, a.Address)
+	sans = append(sans, a.SANs...)
+	if a.ExternalAddress != "" {
+		sans = append(sans, a.ExternalAddress)
+	}
+
+	return util.Unique(sans)
+}
+
 // FromYaml ...
 func FromYaml(filename string) (*ClusterConfig, error) {
 	buf, err := ioutil.ReadFile(filename)

pkg/apis/v1beta1/cluster_test.go

@@ -134,3 +134,38 @@ spec:
 	assert.Equal(t, 1, len(errors))
 	assert.Equal(t, "unsupported network provider: invalidProvider", errors[0].Error())
 }
+
+func TestApiExternalAddress(t *testing.T) {
+	yamlData := `
+apiVersion: k0s.k0sproject.io/v1beta1
+kind: Cluster
+metadata:
+  name: foobar
+spec:
+  api:
+    externalAddress: foo.bar.com
+    address: 1.2.3.4
+`
+
+	c, err := fromYaml(t, yamlData)
+	assert.NoError(t, err)
+	assert.Equal(t, "https://foo.bar.com:6443", c.Spec.API.APIAddress())
+	assert.Equal(t, "https://foo.bar.com:9443", c.Spec.API.K0sControlPlaneAPIAddress())
+}
+
+func TestApiNoExternalAddress(t *testing.T) {
+	yamlData := `
+apiVersion: k0s.k0sproject.io/v1beta1
+kind: Cluster
+metadata:
+  name: foobar
+spec:
+  api:
+    address: 1.2.3.4
+`
+
+	c, err := fromYaml(t, yamlData)
+	assert.NoError(t, err)
+	assert.Equal(t, "https://1.2.3.4:6443", c.Spec.API.APIAddress())
+	assert.Equal(t, "https://1.2.3.4:9443", c.Spec.API.K0sControlPlaneAPIAddress())
+}