fix: Kubernetes autodiscover & register cluster

Author: zeroc0d3

internal/agent/agent.go

@@ -4,6 +4,7 @@ package agent
 import (
 	"context"
 	"fmt"
+	"os"
 	"sync"
 	"time"
 
@@ -123,6 +124,16 @@ func New(cfg *config.Config, logger *zap.Logger) (*Agent, error) {
 		}
 	}
 
+	// Auto-detect Kubernetes: enable collector + sync when running inside a K8s cluster.
+	// KUBERNETES_SERVICE_HOST is injected by the kubelet into every pod.
+	if !cfg.Collector.Kubernetes.Enabled && os.Getenv("KUBERNETES_SERVICE_HOST") != "" {
+		cfg.Collector.Kubernetes.Enabled = true
+		if !cfg.Collector.Kubernetes.SyncToBackend {
+			cfg.Collector.Kubernetes.SyncToBackend = true
+		}
+		logger.Info("Kubernetes environment auto-detected, enabling K8s collector")
+	}
+
 	// Add Kubernetes collector if enabled
 	var k8sSync *exporter.KubernetesSync
 	if cfg.Collector.Kubernetes.Enabled {
@@ -134,11 +145,35 @@ func New(cfg *config.Config, logger *zap.Logger) (*Agent, error) {
 		} else {
 			collectors = append(collectors, k8sCollector)
 			logger.Info("Kubernetes collector enabled",
-				zap.String("cluster", cfg.Collector.Kubernetes.ClusterName),
+				zap.String("cluster", k8sCollector.ClusterName()),
+				zap.String("provider", k8sCollector.ClusterProvider()),
 			)
 
+			// Auto-register cluster with backend if ClusterID is not pre-configured.
+			if cfg.Collector.Kubernetes.SyncToBackend && cfg.Collector.Kubernetes.ClusterID == "" {
+				regCtx, regCancel := context.WithTimeout(context.Background(), 30*time.Second)
+				regResp, regErr := client.AgentRegisterCluster(regCtx, &api.AgentRegisterClusterRequest{
+					Name:     k8sCollector.ClusterName(),
+					Provider: k8sCollector.ClusterProvider(),
+				})
+				regCancel()
+				if regErr != nil {
+					logger.Warn("Failed to auto-register Kubernetes cluster, sync disabled",
+						zap.Error(regErr),
+						zap.String("cluster", k8sCollector.ClusterName()),
+					)
+				} else {
+					cfg.Collector.Kubernetes.ClusterID = regResp.ID
+					logger.Info("Kubernetes cluster auto-registered",
+						zap.String("clusterID", regResp.ID),
+						zap.String("name", regResp.Name),
+						zap.Bool("isNew", regResp.IsNew),
+					)
+				}
+			}
+
 			// Create K8s state sync exporter when sync_to_backend is enabled
-			if cfg.Collector.Kubernetes.SyncToBackend {
+			if cfg.Collector.Kubernetes.SyncToBackend && cfg.Collector.Kubernetes.ClusterID != "" {
 				syncInterval := cfg.Collector.Kubernetes.SyncInterval
 				if syncInterval == 0 {
 					syncInterval = 60 * time.Second

internal/collector/kubernetes/kubernetes.go

@@ -306,6 +306,16 @@ func (k *KubernetesCollector) LastClusterState() *ClusterState {
 	return k.lastState
 }
 
+// ClusterName returns the detected or configured cluster name.
+func (k *KubernetesCollector) ClusterName() string {
+	return k.cfg.ClusterName
+}
+
+// ClusterProvider returns the detected or configured cluster provider.
+func (k *KubernetesCollector) ClusterProvider() string {
+	return k.cfg.ClusterProvider
+}
+
 // SetKubeletFetcher replaces the kubelet stats fetcher (used in tests).
 func (k *KubernetesCollector) SetKubeletFetcher(f KubeletStatsFetcher) {
 	k.kubeletFetcher = f

pkg/api/kubernetes.go

@@ -27,6 +27,23 @@ type RegisterClusterResponse struct {
 	ClusterName string `json:"cluster_name"`
 }
 
+// AgentRegisterClusterRequest is the payload for agent-driven cluster registration.
+// Uses API key auth and is safe to call on every restart (find-or-create semantics).
+type AgentRegisterClusterRequest struct {
+	Name     string            `json:"name"`
+	Provider string            `json:"provider,omitempty"`
+	Version  string            `json:"version,omitempty"`
+	Region   string            `json:"region,omitempty"`
+	Labels   map[string]string `json:"labels,omitempty"`
+}
+
+// AgentRegisterClusterResponse is returned by the agent-register endpoint.
+type AgentRegisterClusterResponse struct {
+	ID    string `json:"id"`
+	Name  string `json:"name"`
+	IsNew bool   `json:"isNew"`
+}
+
 // SyncKubernetesState sends the full cluster state snapshot to the TFO backend.
 func (c *Client) SyncKubernetesState(ctx context.Context, clusterID string, payload interface{}) error {
 	path := fmt.Sprintf("/monitoring/kubernetes/clusters/%s/sync", clusterID)
@@ -54,6 +71,23 @@ func (c *Client) RegisterCluster(ctx context.Context, req *RegisterClusterReques
 	return &result, nil
 }
 
+// AgentRegisterCluster auto-registers a Kubernetes cluster using API key auth.
+// Implements find-or-create — safe to call on every agent restart.
+func (c *Client) AgentRegisterCluster(ctx context.Context, req *AgentRegisterClusterRequest) (*AgentRegisterClusterResponse, error) {
+	resp, err := c.Request(ctx, http.MethodPost, "/monitoring/kubernetes/clusters/agent-register", req)
+	if err != nil {
+		return nil, fmt.Errorf("agent register cluster: %w", err)
+	}
+	if !resp.IsSuccess() {
+		return nil, fmt.Errorf("agent register cluster failed with status %d", resp.StatusCode)
+	}
+	var result AgentRegisterClusterResponse
+	if err := resp.JSON(&result); err != nil {
+		return nil, fmt.Errorf("parse agent register cluster response: %w", err)
+	}
+	return &result, nil
+}
+
 // DeregisterCluster removes a Kubernetes cluster from the TFO backend.
 func (c *Client) DeregisterCluster(ctx context.Context, clusterName string) error {
 	path := fmt.Sprintf("/monitoring/kubernetes/clusters/%s", clusterName)