[Feature] Support adding an observer role in FE to improve query load balancing and scale read workloads

config/crd/bases/starrocks.com_starrocksclusters.yaml

@@ -13601,6 +13601,9 @@ spec:
                     description: (Optional) If specified, the pod's nodeSelector，displayName="Map
                       of nodeSelectors to match when scheduling pods on nodes"
                     type: object
+                  observerNumber:
+                    format: int32
+                    type: integer
                   persistentVolumeClaimRetentionPolicy:
                     description: |-
                       PersistentVolumeClaimRetentionPolicy specifies the retention policy for PersistentVolumeClaims associated with the component.

deploy/starrocks.com_starrocksclusters.yaml

@@ -6413,6 +6413,9 @@ spec:
                     additionalProperties:
                       type: string
                     type: object
+                  observerNumber:
+                    format: int32
+                    type: integer
                   persistentVolumeClaimRetentionPolicy:
                     properties:
                       whenDeleted:

helm-charts/charts/kube-starrocks/charts/starrocks/values.yaml

@@ -195,6 +195,8 @@ starrocksCluster:
 starrocksFESpec:
   # number of replicas to deploy for a FE statefulset.
   replicas: 1
+  # the number of observer for FE.
+  # observerNumber: 0
   image:
     # image sliced by "repository:tag"
     repository: starrocks/fe-ubuntu

helm-charts/charts/kube-starrocks/values.yaml

@@ -311,6 +311,8 @@ starrocks:
   starrocksFESpec:
     # number of replicas to deploy for a FE statefulset.
     replicas: 1
+    # the number of observer for FE.
+    # observerNumber: 0
     image:
       # image sliced by "repository:tag"
       repository: starrocks/fe-ubuntu

pkg/apis/starrocks/v1/labels.go

@@ -40,4 +40,5 @@ const (
 const (
 	COMPONENT_NAME  = "COMPONENT_NAME"
 	FE_SERVICE_NAME = "FE_SERVICE_NAME"
+	OBSERVER_NUMBER = "OBSERVER_NUMBER"
 )

pkg/apis/starrocks/v1/load_type.go

@@ -85,7 +85,6 @@ type StarRocksLoadSpec struct {
 	// +kubebuilder:default=1
 	// +optional
 	Replicas *int32 `json:"replicas,omitempty"`
-
 	// Image for a starrocks deployment.
 	// +optional
 	Image string `json:"image"`
@@ -304,7 +303,6 @@ type StarRocksProbe struct {
 func (spec *StarRocksLoadSpec) GetReplicas() *int32 {
 	return spec.Replicas
 }
-
 func (spec *StarRocksLoadSpec) GetStorageVolumes() []StorageVolume {
 	return spec.StorageVolumes
 }

pkg/apis/starrocks/v1/starrockscluster_types.go

@@ -149,6 +149,8 @@ type StarRocksClusterStatus struct {
 type StarRocksFeSpec struct {
 	StarRocksComponentSpec `json:",inline"`
 
+	ObserverNumber *int32 `json:"observerNumber,omitempty"`
+
 	// +optional
 	// feEnvVars is a slice of environment variables that are added to the pods, the default is empty.
 	FeEnvVars []corev1.EnvVar `json:"feEnvVars,omitempty"`
@@ -243,6 +245,14 @@ func (spec *StarRocksFeProxySpec) GetReplicas() *int32 {
 	return spec.StarRocksLoadSpec.GetReplicas()
 }
 
+func (spec *StarRocksFeSpec) GetObserverNumber() *int32 {
+	var DefaultObserverNumber int32 = 0
+	if spec.ObserverNumber != nil {
+		return spec.ObserverNumber
+	}
+	return &DefaultObserverNumber
+}
+
 // GetHostAliases
 // fe proxy does not have field HostAliases, the reason why implementing this method is
 // that StarRocksFeProxySpec needs to implement SpecInterface interface

pkg/k8sutils/templates/pod/spec.go

@@ -89,7 +89,6 @@ func Envs(spec v1.SpecInterface, config map[string]interface{},
 	feExternalServiceName string, namespace string, envs []corev1.EnvVar) []corev1.EnvVar {
 	// copy envs
 	envs = append([]corev1.EnvVar(nil), envs...)
-
 	keys := make(map[string]bool)
 	for _, env := range envs {
 		keys[env.Name] = true
@@ -142,8 +141,9 @@ func Envs(spec v1.SpecInterface, config map[string]interface{},
 		addEnv(envVar)
 	}
 
-	switch spec.(type) {
+	switch s := spec.(type) {
 	case *v1.StarRocksFeSpec:
+		observerNumber := s.GetObserverNumber()
 		for _, envVar := range []corev1.EnvVar{
 			{
 				Name:  v1.COMPONENT_NAME,
@@ -153,6 +153,10 @@ func Envs(spec v1.SpecInterface, config map[string]interface{},
 				Name:  v1.FE_SERVICE_NAME,
 				Value: feExternalServiceName + "." + namespace,
 			},
+			{
+				Name:  v1.OBSERVER_NUMBER,
+				Value: strconv.FormatInt(int64(*observerNumber), 10),
+			},
 		} {
 			addEnv(envVar)
 		}

pkg/k8sutils/templates/pod/spec_test.go

@@ -18,6 +18,7 @@ import (
 	"fmt"
 	"os"
 	"reflect"
+	"strconv"
 	"testing"
 
 	corev1 "k8s.io/api/core/v1"
@@ -237,6 +238,10 @@ func TestEnvs(t *testing.T) {
 					Name:  v1.FE_SERVICE_NAME,
 					Value: service.ExternalServiceName("test", &v1.StarRocksFeSpec{}) + "." + "ns",
 				},
+				{
+					Name:  v1.OBSERVER_NUMBER,
+					Value: strconv.FormatInt(int64(0), 10),
+				},
 			}...),
 			unsupportedEnvs: "",
 		},