Feature: Support Scaling for Redis Cluster

.azure-pipelines/pipeline.yaml

@@ -25,4 +25,4 @@ extends:
     GithubImageName: ot-container-kit/redis-operator/redis-operator
     BuildDocs: false
     AppVersion: "v0.15.0"
-    GolangVersion: "1.17"
+    GolangVersion: "1.17"

controllers/rediscluster_controller.go

@@ -70,6 +70,33 @@ func (r *RedisClusterReconciler) Reconcile(ctx context.Context, req ctrl.Request
 		return ctrl.Result{RequeueAfter: time.Second * 60}, err
 	}
 
+	// last Leader in redis cluster
+	lastLeaderPod := instance.Name + "-leader-" + strconv.Itoa(int(k8sutils.CheckRedisNodeCount(instance, "leader"))-1)
+	// Check if the cluster is downscaled
+	if leaderReplicas < k8sutils.CheckRedisNodeCount(instance, "leader") {
+
+		//  Imp if the last index of leader sts is not leader make it then
+		// check whether the redis is leader or not ?
+		// if not true then make it leader pod
+
+		if !(k8sutils.VerifyLeaderPod(instance, lastLeaderPod)) {
+			// lastLeaderPod is slaving right now Make it the master Pod
+			// We have to bring a manual failover here to make it a leaderPod
+			// clusterFailover should also include the clusterReplicate since we have to map the followers to new leader
+			k8sutils.ClusterFailover(instance, lastLeaderPod)
+		}
+
+		// Step 1 Rehard the Cluster
+		k8sutils.ReshardRedisCluster(instance)
+		// Step 2 Remove the Follower Node
+		k8sutils.RemoveRedisFollowerNodesFromCluster(instance)
+		// Step 3 Remove the Leader Node
+		k8sutils.RemoveRedisNodeFromCluster(instance)
+		// Step 4 Rebalance the cluster
+		k8sutils.RebalanceRedisCluster(instance)
+		return ctrl.Result{RequeueAfter: time.Second * 100}, nil
+	}
+
 	err = k8sutils.CreateRedisLeader(instance)
 	if err != nil {
 		return ctrl.Result{RequeueAfter: time.Second * 60}, err
@@ -127,7 +154,17 @@ func (r *RedisClusterReconciler) Reconcile(ctx context.Context, req ctrl.Request
 		leaderCount := k8sutils.CheckRedisNodeCount(instance, "leader")
 		if leaderCount != leaderReplicas {
 			reqLogger.Info("Not all leader are part of the cluster...", "Leaders.Count", leaderCount, "Instance.Size", leaderReplicas)
-			k8sutils.ExecuteRedisClusterCommand(instance)
+			if leaderCount <= 2 {
+				k8sutils.ExecuteRedisClusterCommand(instance)
+			} else {
+				if leaderCount < leaderReplicas {
+					// Scale up the cluster
+					// Step 2 : Add Redis Node
+					k8sutils.AddRedisNodeToCluster(instance)
+					// Step 3 Rebalance the cluster using the empty masters
+					k8sutils.RebalanceRedisClusterEmptyMasters(instance)
+				}
+			}
 		} else {
 			if followerReplicas > 0 {
 				reqLogger.Info("All leader are part of the cluster, adding follower/replicas", "Leaders.Count", leaderCount, "Instance.Size", leaderReplicas, "Follower.Replicas", followerReplicas)
@@ -147,6 +184,11 @@ func (r *RedisClusterReconciler) Reconcile(ctx context.Context, req ctrl.Request
 		}
 		return ctrl.Result{RequeueAfter: time.Second * 120}, nil
 	}
+
+	// Check If there is No Empty Master Node
+	if k8sutils.CheckRedisNodeCount(instance, "") == totalReplicas {
+		k8sutils.CheckIfEmptyMasters(instance)
+	}
 	reqLogger.Info("Will reconcile redis cluster operator in again 10 seconds")
 	return ctrl.Result{RequeueAfter: time.Second * 10}, nil
 }