feat: provide machine configuration for KubeSpan and cluster discovery

Fixes #4131

Signed-off-by: Andrey Smirnov <andrey.smirnov@talos-systems.com>

pkg/machinery/config/provider.go

@@ -101,6 +101,7 @@ type MachineNetwork interface {
 	Resolvers() []string
 	Devices() []Device
 	ExtraHosts() []ExtraHost
+	KubeSpan() KubeSpan
 }
 
 // ExtraHost represents a host entry in /etc/hosts.
@@ -207,6 +208,11 @@ type Route interface {
 	Metric() uint32
 }
 
+// KubeSpan configures KubeSpan feature.
+type KubeSpan interface {
+	Enabled() bool
+}
+
 // Time defines the requirements for a config that pertains to time related
 // options.
 type Time interface {
@@ -288,6 +294,7 @@ type ClusterConfig interface {
 	InlineManifests() []InlineManifest
 	AdminKubeconfig() AdminKubeconfig
 	ScheduleOnMasters() bool
+	Discovery() Discovery
 }
 
 // ClusterNetwork defines the requirements for a config that pertains to cluster
@@ -432,3 +439,26 @@ type InlineManifest interface {
 	Name() string
 	Contents() string
 }
+
+// Discovery describes cluster membership discovery.
+type Discovery interface {
+	Enabled() bool
+	Registries() DiscoveryRegistries
+}
+
+// DiscoveryRegistries describes discovery methods.
+type DiscoveryRegistries interface {
+	Kubernetes() KubernetesRegistry
+	Service() ServiceRegistry
+}
+
+// KubernetesRegistry describes Kubernetes discovery registry.
+type KubernetesRegistry interface {
+	Enabled() bool
+}
+
+// ServiceRegistry describes external service discovery registry.
+type ServiceRegistry interface {
+	Enabled() bool
+	Endpoint() string
+}

pkg/machinery/config/types/v1alpha1/v1alpha1_clusterconfig.go

@@ -255,6 +255,11 @@ func (c *ClusterConfig) DNSServiceIPs() ([]net.IP, error) {
 	return talosnet.NthIPInCIDRSet(serviceCIDRs, 10)
 }
 
+// Discovery implements the config.Cluster interface.
+func (c *ClusterConfig) Discovery() config.Discovery {
+	return c.ClusterDiscoveryConfig
+}
+
 type clusterToken string
 
 // ID implements the config.Token interface.

pkg/machinery/config/types/v1alpha1/v1alpha1_discoveryconfig.go

@@ -0,0 +1,49 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package v1alpha1
+
+import (
+	"github.com/talos-systems/talos/pkg/machinery/config"
+	"github.com/talos-systems/talos/pkg/machinery/constants"
+)
+
+// Enabled implements the config.ClusterDiscovery interface.
+func (c ClusterDiscoveryConfig) Enabled() bool {
+	return c.DiscoveryEnabled
+}
+
+// Registries implements the config.ClusterDiscovery interface.
+func (c ClusterDiscoveryConfig) Registries() config.DiscoveryRegistries {
+	return c.DiscoveryRegistries
+}
+
+// Kubernetes implements the config.DiscoveryRegistries interface.
+func (c DiscoveryRegistriesConfig) Kubernetes() config.KubernetesRegistry {
+	return c.RegistryKubernetes
+}
+
+// Service implements the config.DiscoveryRegistries interface.
+func (c DiscoveryRegistriesConfig) Service() config.ServiceRegistry {
+	return c.RegistryService
+}
+
+// Enabled implements the config.KubernetesRegistry interface.
+func (c RegistryKubernetesConfig) Enabled() bool {
+	return !c.RegistryDisabled
+}
+
+// Enabled implements the config.ServiceRegistry interface.
+func (c RegistryServiceConfig) Enabled() bool {
+	return !c.RegistryDisabled
+}
+
+// Endpoint implements the config.ServiceRegistry interface.
+func (c RegistryServiceConfig) Endpoint() string {
+	if c.RegistryEndpoint == "" {
+		return constants.DefaultDiscoveryServiceEndpoint
+	}
+
+	return c.RegistryEndpoint
+}

pkg/machinery/config/types/v1alpha1/v1alpha1_provider.go

@@ -476,6 +476,11 @@ func (n *NetworkConfig) ExtraHosts() []config.ExtraHost {
 	return hosts
 }
 
+// KubeSpan implements the config.Provider interface.
+func (n *NetworkConfig) KubeSpan() config.KubeSpan {
+	return n.NetworkKubeSpan
+}
+
 // IP implements the MachineNetwork interface.
 func (e *ExtraHost) IP() string {
 	return e.HostIP
@@ -872,6 +877,11 @@ func (v *Vlan) ID() uint16 {
 	return v.VlanID
 }
 
+// Enabled implements KubeSpan interface.
+func (k NetworkKubeSpan) Enabled() bool {
+	return k.KubeSpanEnabled
+}
+
 // Disabled implements the config.Provider interface.
 func (t *TimeConfig) Disabled() bool {
 	return t.TimeDisabled

pkg/machinery/config/types/v1alpha1/v1alpha1_types.go

@@ -443,6 +443,19 @@ metadata:
 `),
 		},
 	}
+
+	networkKubeSpanExample = NetworkKubeSpan{
+		KubeSpanEnabled: true,
+	}
+
+	clusterDiscoveryExample = ClusterDiscoveryConfig{
+		DiscoveryEnabled: true,
+		DiscoveryRegistries: DiscoveryRegistriesConfig{
+			RegistryService: RegistryServiceConfig{
+				RegistryEndpoint: constants.DefaultDiscoveryServiceEndpoint,
+			},
+		},
+	}
 )
 
 // Config defines the v1alpha1 configuration file.
@@ -707,6 +720,11 @@ type ClusterConfig struct {
 	//     - value: clusterSchedulerExample
 	SchedulerConfig *SchedulerConfig `yaml:"scheduler,omitempty"`
 	//   description: |
+	//     Configures cluster member discovery.
+	//   examples:
+	//     - value: clusterDiscoveryExample
+	ClusterDiscoveryConfig ClusterDiscoveryConfig `yaml:"discovery,omitempty"`
+	//   description: |
 	//     Etcd specific configuration options.
 	//   examples:
 	//     - value: clusterEtcdExample
@@ -843,6 +861,11 @@ type NetworkConfig struct {
 	//   examples:
 	//     - value: networkConfigExtraHostsExample
 	ExtraHostEntries []*ExtraHost `yaml:"extraHostEntries,omitempty"`
+	//   description: |
+	//     Configures KubeSpan feature.
+	//   examples:
+	//     - value: networkKubeSpanExample
+	NetworkKubeSpan NetworkKubeSpan `yaml:"kubespan,omitempty"`
 }
 
 // InstallConfig represents the installation options for preparing a node.
@@ -1877,3 +1900,52 @@ type ClusterInlineManifest struct {
 	//     - value: '"/etc/kubernetes/auth"'
 	InlineManifestContents string `yaml:"contents"`
 }
+
+// NetworkKubeSpan struct describes KubeSpan configuration.
+type NetworkKubeSpan struct {
+	// description: |
+	//   Enable the KubeSpan feature.
+	//   Cluster discovery should be enabled with .cluster.discovery.enabled for KubeSpan to be enabled.
+	KubeSpanEnabled bool `yaml:"enabled"`
+}
+
+// ClusterDiscoveryConfig struct configures cluster membership discovery.
+type ClusterDiscoveryConfig struct {
+	// description: |
+	//   Enable the cluster membership discovery feature.
+	//   Cluster discovery is based on individual registries which are configured under the registries field.
+	DiscoveryEnabled bool `yaml:"enabled"`
+	// description: |
+	//   Configure registries used for cluster member discovery.
+	DiscoveryRegistries DiscoveryRegistriesConfig `yaml:"registries"`
+}
+
+// DiscoveryRegistriesConfig struct configures cluster membership discovery.
+type DiscoveryRegistriesConfig struct {
+	// description: |
+	//   Kubernetes registry uses Kubernetes API server to discover cluster members and stores additional information
+	//   as annotations on the Node resources.
+	RegistryKubernetes RegistryKubernetesConfig `yaml:"kubernetes"`
+	// description: |
+	//   Service registry is using an external service to push and pull information about cluster members.
+	RegistryService RegistryServiceConfig `yaml:"service"`
+}
+
+// RegistryKubernetesConfig struct configures Kubernetes discovery registry.
+type RegistryKubernetesConfig struct {
+	// description: |
+	//   Disable Kubernetes discovery registry.
+	RegistryDisabled bool `yaml:"disabled,omitempty"`
+}
+
+// RegistryServiceConfig struct configures Kubernetes discovery registry.
+type RegistryServiceConfig struct {
+	// description: |
+	//   Disable external service discovery registry.
+	RegistryDisabled bool `yaml:"disabled,omitempty"`
+	// description: |
+	//   External service endpoint.
+	//   examples:
+	//     - value: 'constants.DefaultDiscoveryServiceEndpoint'
+	RegistryEndpoint string `yaml:"endpoint,omitempty"`
+}