事件中心触发 AKS 上的 Azure Function 运行 with KEDA 不横向扩展

Question

我已经在 AKS 上部署了用 Java 编写的事件中心触发的 Azure 函数。该功能应使用 KEDA 进行横向扩展。该功能已正确触发并正常工作，但当负载增加时它不会扩展。我已经向函数实现添加了睡眠调用，以确保它不会过快地消耗事件并且应该强制扩展，但这也没有显示任何变化。

kubectl get hpa 显示以下输出

NAME                   REFERENCE                TARGETS       MINPODS   MAXPODS   REPLICAS   AGE
keda-hpa-eventlogger   Deployment/eventlogger   64/64 (avg)   1         20        1          3m41s

这似乎是第一个指示某些地方不正确的指标，因为我假设目标列中的第一个数字是事件中心中未处理事件的数量。无论我向集线器注入多少事件，这都保持不变。

函数是使用以下 Kubernetes 部署清单部署的

data:
  AzureWebJobsStorage: <removed>
  FUNCTIONS_WORKER_RUNTIME: amF2YQ==
  EventHubConnectionString: <removed>
apiVersion: v1
kind: Secret
metadata:
  name: eventlogger
---

apiVersion: apps/v1
kind: Deployment
metadata:
  name: eventlogger
  labels:
    app: eventlogger
spec:
  selector:
    matchLabels:
      app: eventlogger
  template:
    metadata:
      labels:
        app: eventlogger
    spec:
      containers:
      - name: eventlogger
        image: <removed>
        env:
        - name: AzureFunctionsJobHost__functions__0
          value: eventloggerHandler
        envFrom:
        - secretRef:
            name: eventlogger
        readinessProbe:
          failureThreshold: 3
          periodSeconds: 10
          successThreshold: 1
          timeoutSeconds: 240
          httpGet:
            path: /
            port: 80
            scheme: HTTP
        startupProbe:
          failureThreshold: 3
          periodSeconds: 10
          successThreshold: 1
          timeoutSeconds: 240
          httpGet:
            path: /
            port: 80
            scheme: HTTP
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: eventlogger
  labels:
    app: eventlogger
spec:
  scaleTargetRef:
    name: eventlogger
  pollingInterval: 5
  cooldownPeriod: 5
  minReplicaCount: 0
  maxReplicaCount: 20
  triggers:
  - type: azure-eventhub
    metadata:
      storageConnectionFromEnv: AzureWebJobsStorage
      connectionFromEnv: EventHubConnectionString
---

事件中心的连接字符串包含 KEDA Event Hub Scaler Documentation 中所述的“EntityPath=”部分，并且对事件中心命名空间具有管理权限。

kubectl describe ScaledObject的输出是

Name:         eventlogger
Namespace:    default
Labels:       app=eventlogger
              scaledobject.keda.sh/name=eventlogger
Annotations:  <none>
API Version:  keda.sh/v1alpha1
Kind:         ScaledObject
Metadata:
  Creation Timestamp:  2022-04-17T10:30:36Z
  Finalizers:
    finalizer.keda.sh
  Generation:  1
  Managed Fields:
    API Version:  keda.sh/v1alpha1
    Fields Type:  FieldsV1
    fieldsV1:
      f:metadata:
        f:annotations:
          .:
          f:kubectl.kubernetes.io/last-applied-configuration:
        f:labels:
          .:
          f:app:
      f:spec:
        .:
        f:cooldownPeriod:
        f:maxReplicaCount:
        f:minReplicaCount:
        f:pollingInterval:
        f:scaleTargetRef:
          .:
          f:name:
        f:triggers:
    Manager:      kubectl-client-side-apply
    Operation:    Update
    Time:         2022-04-17T10:30:36Z
    API Version:  keda.sh/v1alpha1
    Fields Type:  FieldsV1
    fieldsV1:
      f:metadata:
        f:finalizers:
          .:
          v:"finalizer.keda.sh":
        f:labels:
          f:scaledobject.keda.sh/name:
      f:status:
        .:
        f:conditions:
        f:externalMetricNames:
        f:lastActiveTime:
        f:originalReplicaCount:
        f:scaleTargetGVKR:
          .:
          f:group:
          f:kind:
          f:resource:
          f:version:
        f:scaleTargetKind:
    Manager:         keda
    Operation:       Update
    Time:            2022-04-17T10:30:37Z
  Resource Version:  1775052
  UID:               3b6a68c1-c3b9-4cdf-b5d5-41a9721ac661
Spec:
  Cooldown Period:    5
  Max Replica Count:  20
  Min Replica Count:  0
  Polling Interval:   5
  Scale Target Ref:
    Name:  eventlogger
  Triggers:
    Metadata:
      Connection From Env:          EventHubConnectionString
      Storage Connection From Env:  AzureWebJobsStorage
    Type:                           azure-eventhub
Status:
  Conditions:
    Message:  ScaledObject is defined correctly and is ready for scaling
    Reason:   ScaledObjectReady
    Status:   False
    Type:     Ready
    Message:  Scaling is performed because triggers are active
    Reason:   ScalerActive
    Status:   True
    Type:     Active
    Status:   Unknown
    Type:     Fallback
  External Metric Names:
    s0-azure-eventhub-$Default
  Last Active Time:        2022-04-17T10:30:47Z
  Original Replica Count:  1
  Scale Target GVKR:
    Group:            apps
    Kind:             Deployment
    Resource:         deployments
    Version:          v1
  Scale Target Kind:  apps/v1.Deployment
Events:
  Type    Reason              Age   From           Message
  ----    ------              ----  ----           -------
  Normal  KEDAScalersStarted  10s   keda-operator  Started scalers watch
  Normal  ScaledObjectReady   10s   keda-operator  ScaledObject is ready for scaling

所以我有点卡住了，因为我没有看到任何错误，但它仍然没有按预期运行。

版本：

Kubernetes 版本：1.21.9
KEDA 版本：2.6.1 安装使用 kubectl apply -f https://github.com/kedacore/keda/releases/download/v2.6.1/keda-2.6.1.yaml
使用 Java 11 和 host.json 中的 extensionBundle 的 Azure Functions 使用版本 [2.8.4, 3.0.0)

Answer 1

能够找到问题的解决方案。

事件中心触发部署在 AKS 上的 Azure Functions 显示与应用服务上的 Azure Functions 显示相同的扩展特征：

每个分区只能有一个消费者，以允许对每个分区进行排序。此特征否决了 Kubernetes 部署清单中的 maxReplicaCount。

因此，为了解决我自己的问题：通过增加 Event Hub 的分区，我得到每个分区一个 pod，并且 KEDA 按预期扩展工作负载。

事件中心触发 AKS 上的 Azure Function 运行 with KEDA 不横向扩展

Event Hub triggered Azure Function running on AKS with KEDA does not scale out

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