feast-dev · ntkathole · Feb 27, 2026 · Feb 21, 2026 · Feb 23, 2026 · Feb 26, 2026
diff --git a/.secrets.baseline b/.secrets.baseline
@@ -90,6 +90,10 @@
     {
       "path": "detect_secrets.filters.allowlist.is_line_allowlisted"
     },
+    {
+      "path": "detect_secrets.filters.common.is_baseline_file",
+      "filename": ".secrets.baseline"
+    },
     {
       "path": "detect_secrets.filters.common.is_ignored_due_to_verification_policies",
       "min_level": 2
@@ -930,7 +934,7 @@
         "filename": "infra/feast-operator/api/v1/featurestore_types.go",
         "hashed_secret": "44e17306b837162269a410204daaa5ecee4ec22c",
         "is_verified": false,
-        "line_number": 657
+        "line_number": 696
       }
     ],
     "infra/feast-operator/api/v1/zz_generated.deepcopy.go": [
@@ -939,21 +943,21 @@
         "filename": "infra/feast-operator/api/v1/zz_generated.deepcopy.go",
         "hashed_secret": "f914fc9324de1bec1ad13dec94a8ea2ddb41fc87",
         "is_verified": false,
-        "line_number": 615
+        "line_number": 663
       },
       {
         "type": "Secret Keyword",
         "filename": "infra/feast-operator/api/v1/zz_generated.deepcopy.go",
         "hashed_secret": "44e17306b837162269a410204daaa5ecee4ec22c",
         "is_verified": false,
-        "line_number": 1123
+        "line_number": 1206
       },
       {
         "type": "Secret Keyword",
         "filename": "infra/feast-operator/api/v1/zz_generated.deepcopy.go",
         "hashed_secret": "c2028031c154bbe86fd69bef740855c74b927dcf",
         "is_verified": false,
-        "line_number": 1128
+        "line_number": 1211
       }
     ],
     "infra/feast-operator/api/v1alpha1/featurestore_types.go": [
@@ -1152,7 +1156,7 @@
         "filename": "infra/feast-operator/internal/controller/services/services.go",
         "hashed_secret": "36dc326eb15c7bdd8d91a6b87905bcea20b637d1",
         "is_verified": false,
-        "line_number": 164
+        "line_number": 173
       }
     ],
     "infra/feast-operator/internal/controller/services/tls_test.go": [
@@ -1535,5 +1539,5 @@
       }
     ]
   },
-  "generated_at": "2026-02-19T06:53:49Z"
+  "generated_at": "2026-02-26T14:08:35Z"
 }
@@ -65,7 +65,9 @@ spec:
 > _More advanced FeatureStore CR examples can be found in the feast-operator [samples directory](../../infra/feast-operator/config/samples)._
 
 {% hint style="success" %}
-Important note: Scaling a Feature Store Deployment should only be done if the configured data store(s) will support it.
+**Scaling:** The Feast Operator supports horizontal scaling via static replicas, HPA autoscaling, or external autoscalers like [KEDA](https://keda.sh). Scaling requires DB-backed persistence for all enabled services.
 
-Please check the how-to guide for some specific recommendations on [how to scale Feast](./scaling-feast.md).
+See the [Horizontal Scaling with the Feast Operator](./scaling-feast.md#horizontal-scaling-with-the-feast-operator) guide for configuration details, or check the general recommendations on [how to scale Feast](./scaling-feast.md).
 {% endhint %}
+
+> _Sample scaling CRs are available at [`v1_featurestore_scaling_static.yaml`](../../infra/feast-operator/config/samples/v1_featurestore_scaling_static.yaml) and [`v1_featurestore_scaling_hpa.yaml`](../../infra/feast-operator/config/samples/v1_featurestore_scaling_hpa.yaml)._
@@ -23,4 +23,158 @@ However, this process does not scale for large data sets, since it's executed on
 Feast supports pluggable [Compute Engines](../getting-started/components/compute-engine.md), that allow the materialization process to be scaled up.
 Aside from the local process, Feast supports a [Lambda-based materialization engine](https://rtd.feast.dev/en/master/#alpha-lambda-based-engine), and a [Bytewax-based materialization engine](https://rtd.feast.dev/en/master/#bytewax-engine).
 
-Users may also be able to build an engine to scale up materialization using existing infrastructure in their organizations.
+Users may also be able to build an engine to scale up materialization using existing infrastructure in their organizations.
+
+### Horizontal Scaling with the Feast Operator
+
+When running Feast on Kubernetes with the [Feast Operator](./feast-on-kubernetes.md), you can horizontally scale the FeatureStore deployment using `spec.replicas` or HPA autoscaling. The FeatureStore CRD implements the Kubernetes [scale sub-resource](https://kubernetes.io/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definitions/#scale-subresource), so you can also use `kubectl scale`:
+
+```bash
+kubectl scale featurestore/my-feast --replicas=3
+```
+
+**Prerequisites:** Horizontal scaling requires **DB-backed persistence** for all enabled services (online store, offline store, and registry). File-based persistence (SQLite, DuckDB, `registry.db`) is incompatible with multiple replicas because these backends do not support concurrent access from multiple pods.
+
+#### Static Replicas
+
+Set a fixed number of replicas via `spec.replicas`:
+
+```yaml
+apiVersion: feast.dev/v1
+kind: FeatureStore
+metadata:
+  name: sample-scaling
+spec:
+  feastProject: my_project
+  replicas: 3
+  services:
+    onlineStore:
+      persistence:
+        store:
+          type: postgres
+          secretRef:
+            name: feast-data-stores
+    registry:
+      local:
+        persistence:
+          store:
+            type: sql
+            secretRef:
+              name: feast-data-stores
+```
+
+#### Autoscaling with HPA
+
+Configure a HorizontalPodAutoscaler to dynamically scale based on metrics. HPA autoscaling is configured under `services.scaling.autoscaling` and is mutually exclusive with `spec.replicas > 1`:
+
+```yaml
+apiVersion: feast.dev/v1
+kind: FeatureStore
+metadata:
+  name: sample-autoscaling
+spec:
+  feastProject: my_project
+  services:
+    scaling:
+      autoscaling:
+        minReplicas: 2
+        maxReplicas: 10
+        metrics:
+        - type: Resource
+          resource:
+            name: cpu
+            target:
+              type: Utilization
+              averageUtilization: 70
+    onlineStore:
+      persistence:
+        store:
+          type: postgres
+          secretRef:
+            name: feast-data-stores
+      server:
+        resources:
+          requests:
+            cpu: 200m
+            memory: 256Mi
+    registry:
+      local:
+        persistence:
+          store:
+            type: sql
+            secretRef:
+              name: feast-data-stores
+```
+
+{% hint style="info" %}
+When autoscaling is configured, the operator automatically sets the deployment strategy to `RollingUpdate` (instead of the default `Recreate`) to ensure zero-downtime scaling. You can override this by explicitly setting `deploymentStrategy` in the CR.
+{% endhint %}
+
+#### Validation Rules
+
+The operator enforces the following rules:
+- `spec.replicas > 1` and `services.scaling.autoscaling` are **mutually exclusive** -- you cannot set both.
+- Scaling with `replicas > 1` or any `autoscaling` config is **rejected** if any enabled service uses file-based persistence.
+- S3 (`s3://`) and GCS (`gs://`) backed registry file persistence is allowed with scaling, since these object stores support concurrent readers.
+
+#### Using KEDA (Kubernetes Event-Driven Autoscaling)
+
+[KEDA](https://keda.sh) is also supported as an external autoscaler. KEDA should target the FeatureStore's scale sub-resource directly (since it implements the Kubernetes scale API). This is the recommended approach because the operator manages the Deployment's replica count from `spec.replicas` — targeting the Deployment directly would conflict with the operator's reconciliation.
+
+When using KEDA, do **not** set `scaling.autoscaling` or `spec.replicas > 1` -- KEDA manages the replica count through the scale sub-resource.
+
+1. **Ensure DB-backed persistence** -- The CRD's CEL validation rules automatically enforce DB-backed persistence when KEDA scales `spec.replicas` above 1 via the scale sub-resource. The operator also automatically switches the deployment strategy to `RollingUpdate` when `replicas > 1`.
+
+2. **Configure the FeatureStore** with DB-backed persistence:
+
+```yaml
+apiVersion: feast.dev/v1
+kind: FeatureStore
+metadata:
+  name: sample-keda
+spec:
+  feastProject: my_project
+  services:
+    onlineStore:
+      persistence:
+        store:
+          type: postgres
+          secretRef:
+            name: feast-data-stores
+    registry:
+      local:
+        persistence:
+          store:
+            type: sql
+            secretRef:
+              name: feast-data-stores
+```
+
+3. **Create a KEDA `ScaledObject`** targeting the FeatureStore resource:
+
+```yaml
+apiVersion: keda.sh/v1alpha1
+kind: ScaledObject
+metadata:
+  name: feast-scaledobject
+spec:
+  scaleTargetRef:
+    apiVersion: feast.dev/v1
+    kind: FeatureStore
+    name: sample-keda
+  minReplicaCount: 1
+  maxReplicaCount: 10
+  triggers:
+  - type: prometheus
+    metadata:
+      serverAddress: http://prometheus.monitoring.svc:9090
+      metricName: http_requests_total
+      query: sum(rate(http_requests_total{service="feast"}[2m]))
+      threshold: "100"
+```
+
+{% hint style="warning" %}
+KEDA-created HPAs are not owned by the Feast operator. The operator will not interfere with them, but it also will not clean them up if the FeatureStore CR is deleted. You must manage the KEDA `ScaledObject` lifecycle independently.
+{% endhint %}
+
+For the full API reference, see the [FeatureStore CRD reference](../../infra/feast-operator/docs/api/markdown/ref.md).
@@ -18,6 +18,7 @@ package v1
 
 import (
 	appsv1 "k8s.io/api/apps/v1"
+	autoscalingv2 "k8s.io/api/autoscaling/v2"
 	batchv1 "k8s.io/api/batch/v1"
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -67,6 +68,10 @@ const (
 )
 
 // FeatureStoreSpec defines the desired state of FeatureStore
+// +kubebuilder:validation:XValidation:rule="self.replicas <= 1 || !has(self.services) || !has(self.services.scaling) || !has(self.services.scaling.autoscaling)",message="replicas > 1 and services.scaling.autoscaling are mutually exclusive."
+// +kubebuilder:validation:XValidation:rule="self.replicas <= 1 && (!has(self.services) || !has(self.services.scaling) || !has(self.services.scaling.autoscaling)) || (has(self.services) && has(self.services.onlineStore) && has(self.services.onlineStore.persistence) && has(self.services.onlineStore.persistence.store))",message="Scaling requires DB-backed persistence for the online store. Configure services.onlineStore.persistence.store when using replicas > 1 or autoscaling."
+// +kubebuilder:validation:XValidation:rule="self.replicas <= 1 && (!has(self.services) || !has(self.services.scaling) || !has(self.services.scaling.autoscaling)) || (!has(self.services) || !has(self.services.offlineStore) || (has(self.services.offlineStore.persistence) && has(self.services.offlineStore.persistence.store)))",message="Scaling requires DB-backed persistence for the offline store. Configure services.offlineStore.persistence.store when using replicas > 1 or autoscaling."
+// +kubebuilder:validation:XValidation:rule="self.replicas <= 1 && (!has(self.services) || !has(self.services.scaling) || !has(self.services.scaling.autoscaling)) || (has(self.services) && has(self.services.registry) && (has(self.services.registry.remote) || (has(self.services.registry.local) && has(self.services.registry.local.persistence) && (has(self.services.registry.local.persistence.store) || (has(self.services.registry.local.persistence.file) && has(self.services.registry.local.persistence.file.path) && (self.services.registry.local.persistence.file.path.startsWith('s3://') || self.services.registry.local.persistence.file.path.startsWith('gs://')))))))",message="Scaling requires DB-backed or remote registry. Configure registry.local.persistence.store or use a remote registry when using replicas > 1 or autoscaling. S3/GCS-backed registry is also allowed."
 type FeatureStoreSpec struct {
 	// +kubebuilder:validation:Pattern="^[A-Za-z0-9][A-Za-z0-9_-]*$"
 	// FeastProject is the Feast project id. This can be any alphanumeric string with underscores and hyphens, but it cannot start with an underscore or hyphen. Required.
@@ -76,6 +81,11 @@ type FeatureStoreSpec struct {
 	AuthzConfig     *AuthzConfig          `json:"authz,omitempty"`
 	CronJob         *FeastCronJob         `json:"cronJob,omitempty"`
 	BatchEngine     *BatchEngineConfig    `json:"batchEngine,omitempty"`
+	// Replicas is the desired number of pod replicas. Used by the scale sub-resource.
+	// Mutually exclusive with services.scaling.autoscaling.
+	// +kubebuilder:default=1
+	// +kubebuilder:validation:Minimum=1
+	Replicas *int32 `json:"replicas"`
 }
 
 // FeastProjectDir defines how to create the feast project directory.
@@ -301,6 +311,35 @@ type FeatureStoreServices struct {
 	DisableInitContainers bool `json:"disableInitContainers,omitempty"`
 	// Volumes specifies the volumes to mount in the FeatureStore deployment. A corresponding `VolumeMount` should be added to whichever feast service(s) require access to said volume(s).
 	Volumes []corev1.Volume `json:"volumes,omitempty"`
+	// Scaling configures horizontal scaling for the FeatureStore deployment (e.g. HPA autoscaling).
+	// For static replicas, use spec.replicas instead.
+	Scaling *ScalingConfig `json:"scaling,omitempty"`
+}
+
+// ScalingConfig configures horizontal scaling for the FeatureStore deployment.
+type ScalingConfig struct {
+	// Autoscaling configures a HorizontalPodAutoscaler for the FeatureStore deployment.
+	// Mutually exclusive with spec.replicas.
+	// +optional
+	Autoscaling *AutoscalingConfig `json:"autoscaling,omitempty"`
+}
+
+// AutoscalingConfig defines HPA settings for the FeatureStore deployment.
+type AutoscalingConfig struct {
+	// MinReplicas is the lower limit for the number of replicas. Defaults to 1.
+	// +kubebuilder:validation:Minimum=1
+	// +optional
+	MinReplicas *int32 `json:"minReplicas,omitempty"`
+	// MaxReplicas is the upper limit for the number of replicas. Required.
+	// +kubebuilder:validation:Minimum=1
+	MaxReplicas int32 `json:"maxReplicas"`
+	// Metrics contains the specifications for which to use to calculate the desired replica count.
+	// If not set, defaults to 80% CPU utilization.
+	// +optional
+	Metrics []autoscalingv2.MetricSpec `json:"metrics,omitempty"`
+	// Behavior configures the scaling behavior of the target.
+	// +optional
+	Behavior *autoscalingv2.HorizontalPodAutoscalerBehavior `json:"behavior,omitempty"`
 }
 
 // OfflineStore configures the offline store service
@@ -690,6 +729,20 @@ type FeatureStoreStatus struct {
 	FeastVersion     string             `json:"feastVersion,omitempty"`
 	Phase            string             `json:"phase,omitempty"`
 	ServiceHostnames ServiceHostnames   `json:"serviceHostnames,omitempty"`
+	// Replicas is the current number of ready pod replicas (used by the scale sub-resource).
+	Replicas int32 `json:"replicas,omitempty"`
+	// Selector is the label selector for pods managed by the FeatureStore deployment (used by the scale sub-resource).
+	Selector string `json:"selector,omitempty"`
+	// ScalingStatus reports the current scaling state of the FeatureStore deployment.
+	ScalingStatus *ScalingStatus `json:"scalingStatus,omitempty"`
+}
+
+// ScalingStatus reports the observed scaling state.
+type ScalingStatus struct {
+	// CurrentReplicas is the current number of pod replicas.
+	CurrentReplicas int32 `json:"currentReplicas,omitempty"`
+	// DesiredReplicas is the desired number of pod replicas.
+	DesiredReplicas int32 `json:"desiredReplicas,omitempty"`
 }
 
 // ServiceHostnames defines the service hostnames in the format of <domain>:<port>, e.g. example.svc.cluster.local:80
@@ -706,6 +759,7 @@ type ServiceHostnames struct {
 // +kubebuilder:resource:shortName=feast
 // +kubebuilder:printcolumn:name="Status",type=string,JSONPath=`.status.phase`
 // +kubebuilder:printcolumn:name="Age",type=date,JSONPath=`.metadata.creationTimestamp`
+// +kubebuilder:subresource:scale:specpath=.spec.replicas,statuspath=.status.replicas,selectorpath=.status.selector
 // +kubebuilder:storageversion
 
 // FeatureStore is the Schema for the featurestores API