feat(slimfaas): scale down statefulset (#28)

README.md

@@ -3,7 +3,7 @@
 ![SlimFaas.png](https://github.com/AxaFrance/SlimFaas/blob/main/documentation/SlimFaas.png)
 
 Why use SlimFaas ?
-- Scale to 0 after a period of inactivity
+- Scale to 0 after a period of inactivity (work with deployment and statefulset)
 - Synchronous HTTP calls
 - Asynchronous HTTP calls
   - Allows you to limit the number of parallel HTTP requests for each underlying function
@@ -33,6 +33,8 @@ kubectl apply -f deployment-slimfaas.yml
 # Install three instances of fibonacci functions
 # fibonacci1, fibonacci2 and fibonacci3
 kubectl apply -f deployment-functions.yml
+# Install MySql
+kubectl apply -f deployment-mysql.yml
 # to run Single Page webapp demo (optional)
 docker run -p 8000:8000 --rm axaguildev/fibonacci-webapp:latest
 ```
@@ -132,6 +134,7 @@ spec:
         SlimFaas/ReplicasStartAsSoonAsOneFunctionRetrieveARequest: "false"
         SlimFaas/TimeoutSecondBeforeSetReplicasMin: "300"
         SlimFaas/NumberParallelRequest : "10"
+        SlimFaas/DependsOn : "mysql,fibonacci2" # comma separated list of deployment of statefulset names
     spec:
       serviceAccountName: default
       containers:
@@ -271,6 +274,10 @@ spec:
   - Scale down to SlimFaas/ReplicasMin after this period of inactivity in seconds
 - SlimFaas/NumberParallelRequest : "10"
   - Limit the number of parallel HTTP requests for each underlying function
+- SlimFaas/DependsOn : ""
+  - Comma separated list of deployment names or statefulset names
+  - Pods will be scaled up only if all pods in this list are in ready state with the minimum number of replicas superior or equal to ReplicasAtStart
+  - This property is useful if you want to scale up your pods only if your database is ready for example
 
 ## Why SlimFaas ?
 
@@ -319,11 +326,10 @@ Why .NET ?
 
 ## Videos
 
-- French : https://www.youtube.com/watch?v=Lvd6FCuCZPI 
+- French : https://www.youtube.com/watch?v=Lvd6FCuCZPI
 - English: https://www.youtube.com/watch?hxRfvJhWW1w
 
 ## What Next ?
 
 1. Different scale down mode depending from configuration and current hour
-2. Allow to scale down also statefulset pods
-3. Scale up dynamically from SlimFaas
+2. Scale up dynamically from SlimFaas

demo/deployment-functions.yml

@@ -18,6 +18,7 @@ spec:
         SlimFaas/ReplicasStartAsSoonAsOneFunctionRetrieveARequest: "false"
         SlimFaas/TimeoutSecondBeforeSetReplicasMin: "10"
         SlimFaas/NumberParallelRequest : "10"
+        SlimFaas/DependsOn: "fibonacci2"
     spec:
       serviceAccountName: default
       containers:
@@ -59,7 +60,6 @@ spec:
         SlimFaas/Function: "true"
         SlimFaas/ReplicasMin: "0"
         SlimFaas/ReplicasAtStart: "1"
-        SlimFaas/ReplicasStartAsSoonAsOneFunctionRetrieveARequest: "true"
         SlimFaas/TimeoutSecondBeforeSetReplicasMin: "10"
         SlimFaas/NumberParallelRequest : "10"
     spec:
@@ -106,6 +106,7 @@ spec:
         SlimFaas/ReplicasStartAsSoonAsOneFunctionRetrieveARequest: "false"
         SlimFaas/TimeoutSecondBeforeSetReplicasMin: "10"
         SlimFaas/NumberParallelRequest : "10"
+        SlimFaas/DependsOn: "mysql"
     spec:
       serviceAccountName: default
       containers:

demo/deployment-mysql.yml

@@ -0,0 +1,75 @@
+apiVersion: v1
+kind: Secret
+metadata:
+  name: mysql-secret
+type: kubernetes.io/basic-auth
+stringData:
+  password: "test1234"
+---
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: mysql-pv-claim
+spec:
+  accessModes:
+    - ReadWriteOnce
+  resources:
+    requests:
+      storage: 1Gi
+---
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: mysql
+spec:
+  serviceName: mysql
+  selector:
+    matchLabels:
+      app: mysql
+  template:
+    metadata:
+      labels:
+        app: mysql
+      annotations:
+        SlimFaas/Function: "true"
+        SlimFaas/ReplicasMin: "0"
+        SlimFaas/ReplicasAtStart: "1"
+        SlimFaas/ReplicasStartAsSoonAsOneFunctionRetrieveARequest: "true"
+        SlimFaas/TimeoutSecondBeforeSetReplicasMin: "60"
+    spec:
+      containers:
+        - image: mysql:5.6
+          name: mysql
+          env:
+            - name: MYSQL_ROOT_PASSWORD
+              valueFrom:
+                secretKeyRef:
+                  name: mysql-secret
+                  key: password
+          ports:
+            - containerPort: 3306
+              name: mysql
+          volumeMounts:
+            - name: mysql-persistent-storage
+              mountPath: /var/lib/mysql
+          resources:
+            limits:
+              cpu: 600m
+              memory: 1024Mi
+            requests:
+              cpu: 300m
+              memory: 512Mi
+      volumes:
+        - name: mysql-persistent-storage
+          persistentVolumeClaim:
+            claimName: mysql-pv-claim
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: mysql
+spec:
+  ports:
+    - port: 3306
+  selector:
+    app: mysql

src/SlimFaas/EnvironmentVariables.cs

@@ -2,6 +2,7 @@ namespace SlimFaas;
 
 public static class EnvironmentVariables
 {
+
     public const string SlimFaasCorsAllowOrigin = "SLIMFAAS_CORS_ALLOW_ORIGIN";
     public const string SlimFaasCorsAllowOriginDefault = "*";
 

src/SlimFaas/Kubernetes/KubernetesService.cs

@@ -1,21 +1,32 @@
 using System.Diagnostics.CodeAnalysis;
 using System.Text;
+using DotNext.Collections.Generic;
 using k8s;
 using k8s.Autorest;
 using k8s.Models;
 
 namespace SlimFaas.Kubernetes;
 
-public record ReplicaRequest(string Deployment, string Namespace, int Replicas);
+public enum PodType
+{
+    Deployment,
+    StatefulSet
+}
+
+public record ReplicaRequest(string Deployment, string Namespace, int Replicas, PodType PodType);
 
 public record SlimFaasDeploymentInformation(int Replicas, IList<PodInformation> Pods);
 
 public record DeploymentsInformations(IList<DeploymentInformation> Functions, SlimFaasDeploymentInformation SlimFaas);
 
 public record DeploymentInformation(string Deployment, string Namespace, IList<PodInformation> Pods, int Replicas,
-    int ReplicasAtStart = 1, int ReplicasMin = 0, int TimeoutSecondBeforeSetReplicasMin = 300,
+    int ReplicasAtStart = 1,
+    int ReplicasMin = 0,
+    int TimeoutSecondBeforeSetReplicasMin = 300,
     int NumberParallelRequest = 10,
-    bool ReplicasStartAsSoonAsOneFunctionRetrieveARequest = false);
+    bool ReplicasStartAsSoonAsOneFunctionRetrieveARequest = false,
+    PodType PodType = PodType.Deployment,
+    IList<string>? DependsOn = null);
 
 public record PodInformation(string Name, bool? Started, bool? Ready, string Ip, string DeploymentName);
 
@@ -25,6 +36,7 @@ public class KubernetesService : IKubernetesService
     private const string ReplicasMin = "SlimFaas/ReplicasMin";
     private const string Function = "SlimFaas/Function";
     private const string ReplicasAtStart = "SlimFaas/ReplicasAtStart";
+    private const string DependsOn = "SlimFaas/DependsOn";
 
     private const string ReplicasStartAsSoonAsOneFunctionRetrieveARequest =
         "SlimFaas/ReplicasStartAsSoonAsOneFunctionRetrieveARequest";
@@ -48,10 +60,20 @@ public KubernetesService(ILogger<KubernetesService> logger, bool useKubeConfig)
     {
         try
         {
-            using k8s.Kubernetes client = new k8s.Kubernetes(_k8SConfig);
+            using k8s.Kubernetes client = new(_k8SConfig);
             string patchString = $"{{\"spec\": {{\"replicas\": {request.Replicas}}}}}";
-            V1Patch patch = new V1Patch(patchString, V1Patch.PatchType.MergePatch);
-            await client.PatchNamespacedDeploymentScaleAsync(patch, request.Deployment, request.Namespace);
+            V1Patch patch = new(patchString, V1Patch.PatchType.MergePatch);
+            switch (request.PodType)
+            {
+                case PodType.Deployment:
+                    await client.PatchNamespacedDeploymentScaleAsync(patch, request.Deployment, request.Namespace);
+                    break;
+                case PodType.StatefulSet:
+                    await client.PatchNamespacedStatefulSetScaleAsync(patch, request.Deployment, request.Namespace);
+                    break;
+                default:
+                    throw new ArgumentOutOfRangeException();
+            }
         }
         catch (HttpOperationException e)
         {
@@ -68,7 +90,7 @@ public async Task<DeploymentsInformations> ListFunctionsAsync(string kubeNamespa
         try
         {
             IList<DeploymentInformation>? deploymentInformationList = new List<DeploymentInformation>();
-            using k8s.Kubernetes client = new k8s.Kubernetes(_k8SConfig);
+            using k8s.Kubernetes client = new(_k8SConfig);
             Task<V1DeploymentList>? deploymentListTask = client.ListNamespacedDeploymentAsync(kubeNamespace);
             Task<V1PodList>? podListTask = client.ListNamespacedPodAsync(kubeNamespace);
             Task<V1StatefulSetList>? statefulSetListTask = client.ListNamespacedStatefulSetAsync(kubeNamespace);
@@ -85,33 +107,8 @@ public async Task<DeploymentsInformations> ListFunctionsAsync(string kubeNamespa
                             podList.Where(p => p.Name.StartsWith(deploymentListItem.Metadata.Name)).ToList()))
                 .FirstOrDefault();
 
-            foreach (V1Deployment? deploymentListItem in deploymentList.Items)
-            {
-                IDictionary<string, string>? annotations = deploymentListItem.Spec.Template.Metadata.Annotations;
-                if (annotations == null || !annotations.ContainsKey(Function) ||
-                    annotations[Function].ToLower() != "true")
-                {
-                    continue;
-                }
-
-                DeploymentInformation deploymentInformation = new DeploymentInformation(
-                    deploymentListItem.Metadata.Name,
-                    kubeNamespace,
-                    podList.Where(p => p.DeploymentName == deploymentListItem.Metadata.Name).ToList(),
-                    deploymentListItem.Spec.Replicas ?? 0,
-                    annotations.ContainsKey(ReplicasAtStart)
-                        ? int.Parse(annotations[ReplicasAtStart])
-                        : 1, annotations.ContainsKey(ReplicasMin)
-                        ? int.Parse(annotations[ReplicasMin])
-                        : 1, annotations.ContainsKey(TimeoutSecondBeforeSetReplicasMin)
-                        ? int.Parse(annotations[TimeoutSecondBeforeSetReplicasMin])
-                        : 300, annotations.ContainsKey(NumberParallelRequest)
-                        ? int.Parse(annotations[NumberParallelRequest])
-                        : 10, annotations.ContainsKey(
-                                  ReplicasStartAsSoonAsOneFunctionRetrieveARequest) &&
-                              annotations[ReplicasStartAsSoonAsOneFunctionRetrieveARequest].ToLower() == "true");
-                deploymentInformationList.Add(deploymentInformation);
-            }
+            AddDeployments(kubeNamespace, deploymentList, podList, deploymentInformationList);
+            AddStatefulSets(kubeNamespace, statefulSetList, podList, deploymentInformationList);
 
             return new DeploymentsInformations(deploymentInformationList,
                 slimFaasDeploymentInformation ?? new SlimFaasDeploymentInformation(1, new List<PodInformation>()));
@@ -124,6 +121,72 @@ public async Task<DeploymentsInformations> ListFunctionsAsync(string kubeNamespa
         }
     }
 
+    private static void AddDeployments(string kubeNamespace, V1DeploymentList deploymentList, IEnumerable<PodInformation> podList,
+        IList<DeploymentInformation> deploymentInformationList)
+    {
+        foreach (V1Deployment? deploymentListItem in deploymentList.Items)
+        {
+            IDictionary<string, string>? annotations = deploymentListItem.Spec.Template.Metadata.Annotations;
+            if (annotations == null || !annotations.ContainsKey(Function) ||
+                annotations[Function].ToLower() != "true")
+            {
+                continue;
+            }
+
+            DeploymentInformation deploymentInformation = new(
+                deploymentListItem.Metadata.Name,
+                kubeNamespace,
+                podList.Where(p => p.DeploymentName == deploymentListItem.Metadata.Name).ToList(),
+                deploymentListItem.Spec.Replicas ?? 0,
+                annotations.ContainsKey(ReplicasAtStart)
+                    ? int.Parse(annotations[ReplicasAtStart])
+                    : 1, annotations.ContainsKey(ReplicasMin)
+                    ? int.Parse(annotations[ReplicasMin])
+                    : 1, annotations.ContainsKey(TimeoutSecondBeforeSetReplicasMin)
+                    ? int.Parse(annotations[TimeoutSecondBeforeSetReplicasMin])
+                    : 300, annotations.ContainsKey(NumberParallelRequest)
+                    ? int.Parse(annotations[NumberParallelRequest])
+                    : 10, annotations.ContainsKey(
+                              ReplicasStartAsSoonAsOneFunctionRetrieveARequest) &&
+                          annotations[ReplicasStartAsSoonAsOneFunctionRetrieveARequest].ToLower() == "true", PodType.Deployment,
+                annotations.ContainsKey(DependsOn) ? annotations[DependsOn].Split(',').ToList() : new List<string>());
+            deploymentInformationList.Add(deploymentInformation);
+        }
+    }
+
+    private static void AddStatefulSets(string kubeNamespace, V1StatefulSetList deploymentList, IEnumerable<PodInformation> podList,
+        IList<DeploymentInformation> deploymentInformationList)
+    {
+        foreach (V1StatefulSet? deploymentListItem in deploymentList.Items)
+        {
+            IDictionary<string, string>? annotations = deploymentListItem.Spec.Template.Metadata.Annotations;
+            if (annotations == null || !annotations.ContainsKey(Function) ||
+                annotations[Function].ToLower() != "true")
+            {
+                continue;
+            }
+
+            DeploymentInformation deploymentInformation = new(
+                deploymentListItem.Metadata.Name,
+                kubeNamespace,
+                podList.Where(p => p.DeploymentName == deploymentListItem.Metadata.Name).ToList(),
+                deploymentListItem.Spec.Replicas ?? 0,
+                annotations.ContainsKey(ReplicasAtStart)
+                    ? int.Parse(annotations[ReplicasAtStart])
+                    : 1, annotations.ContainsKey(ReplicasMin)
+                    ? int.Parse(annotations[ReplicasMin])
+                    : 1, annotations.ContainsKey(TimeoutSecondBeforeSetReplicasMin)
+                    ? int.Parse(annotations[TimeoutSecondBeforeSetReplicasMin])
+                    : 300, annotations.ContainsKey(NumberParallelRequest)
+                    ? int.Parse(annotations[NumberParallelRequest])
+                    : 10, annotations.ContainsKey(
+                              ReplicasStartAsSoonAsOneFunctionRetrieveARequest) &&
+                          annotations[ReplicasStartAsSoonAsOneFunctionRetrieveARequest].ToLower() == "true", PodType.StatefulSet,
+                annotations.ContainsKey(DependsOn) ? annotations[DependsOn].Split(',').ToList() : new List<string>());
+            deploymentInformationList.Add(deploymentInformation);
+        }
+    }
+
     private static IEnumerable<PodInformation> MapPodInformations(V1PodList v1PodList)
     {
         foreach (V1Pod? item in v1PodList.Items)