diff --git a/api/v1alpha1/condition.go b/api/v1alpha1/condition.go
index a2ea5b028..557855db4 100644
--- a/api/v1alpha1/condition.go
+++ b/api/v1alpha1/condition.go
@@ -32,6 +32,8 @@ const (
 	TypeReady ConditionType = "Ready"
 	// TypeUnknown resources are unknown to the system
 	TypeUnknown ConditionType = "Unknown"
+	// TypeUnavailable resources are unavailable
+	TypeUnavailable ConditionType = "Unavailable"
 )
 
 // A ConditionReason represents the reason a resource is in a condition.
diff --git a/controllers/llm_controller.go b/controllers/llm_controller.go
index 0df542135..491e61f3f 100644
--- a/controllers/llm_controller.go
+++ b/controllers/llm_controller.go
@@ -18,11 +18,18 @@ package controllers
 
 import (
 	"context"
+	"fmt"
+	"net/http"
 
+	"github.com/go-logr/logr"
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/log"
+	"sigs.k8s.io/controller-runtime/pkg/reconcile"
 
 	arcadiav1alpha1 "github.com/kubeagi/arcadia/api/v1alpha1"
 )
@@ -47,10 +54,26 @@ type LLMReconciler struct {
 // For more details, check Reconcile and its Result here:
 // - https://pkg.go.dev/sigs.k8s.io/controller-runtime@v0.12.2/pkg/reconcile
 func (r *LLMReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
-	_ = log.FromContext(ctx)
+	logger := log.FromContext(ctx)
+	logger.Info("Reconciling LLM resource")
 
-	// TODO(user): your logic here
+	// Fetch the LLM instance
+	instance := &arcadiav1alpha1.LLM{}
+	err := r.Get(ctx, req.NamespacedName, instance)
+	if err != nil {
+		if errors.IsNotFound(err) {
+			// LLM instance has been deleted.
+			return reconcile.Result{}, nil
+		}
+		return ctrl.Result{}, client.IgnoreNotFound(err)
+	}
 
+	err = r.CheckLLM(ctx, logger, instance)
+	if err != nil {
+		return ctrl.Result{}, err
+	}
+
+	logger.Info("Instance is updated and synchronized")
 	return ctrl.Result{}, nil
 }
 
@@ -60,3 +83,80 @@ func (r *LLMReconciler) SetupWithManager(mgr ctrl.Manager) error {
 		For(&arcadiav1alpha1.LLM{}).
 		Complete(r)
 }
+
+// CheckLLM updates new LLM instance.
+func (r *LLMReconciler) CheckLLM(ctx context.Context, logger logr.Logger, instance *arcadiav1alpha1.LLM) error {
+	logger.Info("Checking LLM instance")
+	// Check new URL/Auth availability
+	err := r.TestLLMAvailability(instance, logger)
+	if err != nil {
+		// Set status to unavailable
+		instance.Status.SetConditions(arcadiav1alpha1.Condition{
+			Type:               arcadiav1alpha1.TypeUnavailable,
+			Status:             corev1.ConditionFalse,
+			Reason:             arcadiav1alpha1.ReasonUnavailable,
+			Message:            err.Error(),
+			LastTransitionTime: metav1.Now(),
+		})
+	} else {
+		// Set status to available
+		instance.Status.SetConditions(arcadiav1alpha1.Condition{
+			Type:               arcadiav1alpha1.TypeReady,
+			Status:             corev1.ConditionTrue,
+			Reason:             arcadiav1alpha1.ReasonAvailable,
+			Message:            "Available",
+			LastTransitionTime: metav1.Now(),
+			LastSuccessfulTime: metav1.Now(),
+		})
+	}
+	return r.Client.Status().Update(ctx, instance)
+}
+
+// TestLLMAvailability tests LLM availability.
+func (r *LLMReconciler) TestLLMAvailability(instance *arcadiav1alpha1.LLM, logger logr.Logger) error {
+	logger.Info("Testing LLM availability")
+	testURL := instance.Spec.URL + "/v1/models"
+
+	if instance.Spec.Auth == "" {
+		return fmt.Errorf("auth is empty")
+	}
+
+	// get auth by secret name
+	secret := &corev1.Secret{}
+	err := r.Get(context.TODO(), client.ObjectKey{Name: instance.Spec.Auth, Namespace: instance.Namespace}, secret)
+	if err != nil {
+		return err
+	}
+
+	auth := "Bearer " + string(secret.Data["apiKey"])
+
+	err = SendTestRequest("GET", testURL, auth)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func SendTestRequest(method string, url string, auth string) error {
+	req, err := http.NewRequest(method, url, nil)
+	if err != nil {
+		return err
+	}
+
+	req.Header.Set("Authorization", auth)
+	req.Header.Set("Content-Type", "application/json")
+
+	cli := &http.Client{}
+	resp, err := cli.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("returns unexpected status code: %d", resp.StatusCode)
+	}
+
+	return nil
+}