Container Service for Kubernetes:ECS-based elastic inference

Procedure

1. Create an elastic node pool.

   1. Log on to the ACK console.

   2. In the left-side navigation pane of the ACK console, click Clusters.

   3. On the Clusters page, find the cluster that you want to manage and click the name of the cluster or click Details in the Actions column. The details page of the cluster appears.

   4. In the left-side navigation pane of the details page, choose Nodes > Node Pools.

   5. In the upper-right corner of the Node Pools page, click Create Node Pool.

   6. In the Create Node Pool dialog box, set the parameters and click Confirm Order. The following table describes the key parameters. For more information about other parameters, see Create an ACK Pro cluster.

      Parameter	Description
      Auto Scaling	Select Enable Auto Scaling.
      Billing Method	Select Preemptible Instance.
      Node Label	Click Show Advanced Options. In the Node Label section, set Key to inference and Value to tensorflow.
      Scaling Policy	Click Show Advanced Options. In the Scaling Policy section, select Cost Optimization, set Percentage of Pay-as-you-go Instances to 30%, and turn on Enable Supplemental Pay-as-you-go Instances.

2. Upload the trained model to an Object Storage Service (OSS) bucket. For more information, see Upload objects.

3. Create a persistent volume (PV) and a persistent volume claim (PVC).

   1. Create a file named pvc.yaml and copy the following content into the file:

      apiVersion: v1
      kind: PersistentVolume
      metadata:
        name: model-csi-pv
      spec:
        capacity:
          storage: 5Gi
        accessModes:
          - ReadWriteMany
        persistentVolumeReclaimPolicy: Retain
        csi:
          driver: ossplugin.csi.alibabacloud.com
          volumeHandle: model-csi-pv // The value must be the same as the name of the PV. 
          volumeAttributes:
            bucket: "<Your Bucket>"
            url: "<Your oss url>"
            akId: "<Your Access Key Id>"
            akSecret: "<Your Access Key Secret>"
            otherOpts: "-o max_stat_cache_size=0 -o allow_other"
      ---
      apiVersion: v1
      kind: PersistentVolumeClaim
      metadata:
        name: model-pvc
      spec:
        accessModes:
        - ReadWriteMany
        resources:
          requests:
            storage: 5Gi

      Parameter	Description
      bucket	The name of the OSS bucket, which is globally unique in OSS. For more information, see Bucket naming conventions.
      url	The URL that is used to access an object in the bucket. For more information, see Obtain the URL of a single object or the URLs of multiple objects.
      akId	The AccessKey ID and AccessKey secret that are used to access the OSS bucket. We recommend that you access the OSS bucket as a Resource Access Management (RAM) user. For more information, see Create an AccessKey pair.
      akSecret
      otherOpts	Custom parameters for mounting the OSS bucket. Set -o max_stat_cache_size=0 to disable metadata caching. If this feature is disabled, the system retrieves the latest metadata from OSS each time it attempts to access objects in OSS. Set -o allow_other to allow other users to access the OSS bucket that you mounted. For more information about other parameters, see Custom parameters supported by ossfs.

   2. Run the following command to create the PV and PVC:

      kubectl apply -f pvc.yaml

4. Run the following command to deploy the inference service:

   arena serve tensorflow \
     --name=bert-tfserving \
     --model-name=chnsenticorp  \
     --selector=inference:tensorflow \
     --gpus=1  \
     --image=tensorflow/serving:1.15.0-gpu \
     --data=model-pvc:/models \
     --model-path=/models/tensorflow \
     --version-policy=specific:1623831335 \
     --limits=nvidia.com/gpu=1 \
     --requests=nvidia.com/gpu=1 

   Parameter	Description
   selector	The selector parameter is used to select the pods for the TensorFlow training job based on labels. In this example, the value is set to inference: tensorflow.
   limits: nvidia.com/gpu	The maximum number of GPUs that can be used by the service.
   requests: nvidia.com/gpu	The minimum number of GPUs that are required by the service.
   model-name	The name of the model.
   model-path	The path of the model.

5. Configure a Horizontal Pod Autoscaler (HPA). The HPA can automatically adjust the number of replicated pods in a Kubernetes cluster based on workloads.

   1. Create a file named hpa.yaml and copy the following content into the file:

      apiVersion: autoscaling/v2beta1
      kind: HorizontalPodAutoscaler
      metadata:
        name: bert-tfserving-hpa
      spec:
        scaleTargetRef:
          apiVersion: apps/v1
          kind: Deployment
          name: bert-tfserving-202107141745-tensorflow-serving
        minReplicas: 1
        maxReplicas: 10
        metrics:
        - type: External
          external:
            metricName: sls_ingress_qps
            metricSelector:
              matchLabels:
                sls.project: "k8s-log-c210fbedb96674b9eaf15f2dc47d169a8"
                sls.logstore: "nginx-ingress"
                sls.ingress.route: "default-bert-tfserving-202107141745-tensorflow-serving-8501"
            targetAverageValue: 10

      Parameter	Description
      scaleTargetRef	The object to which the HPA is bound. In this example, the value is set to the name of the Deployment of the inference service.
      minReplicas	The minimum number of replicated pods.
      maxReplicas	The maximum number of replicated pods.
      sls.project	The name of the Simple Log Service project that is used by the cluster. The value of the parameter must be in the format of k8s-log-{cluster id}.
      sls.logstore	The name of the Simple Log Service Logstore. The default value is nginx-ingress.
      sls.ingress.route	The Ingress that is used to expose the service. In this example, the value is set to {namespace}-{service name}-{service port}.
      metricname	The metric name. In this example, the value is set to sls_ingress_qps.
      targetaverageValue	The queries per second (QPS) value that triggers scale-out activities. In this example, the value of this parameter is set to 10. A scale-out activity is triggered when the QPS value is greater than 10.

   2. Run the following command to deploy the HPA:

      kubectl apply -f hpa.yaml

6. Configure an Internet-facing Ingress.

   By default, the inference service that is deployed by running the arena serve tensorflow command is assigned only a cluster IP address. The service cannot be accessed over the Internet. Therefore, you must create an Internet-facing Ingress for the inference service.

   1. Log on to the ACK console. In the left-side navigation pane, click Clusters.

   2. On the Clusters page, click the name of the cluster that you want to manage and choose Network > Ingresses in the left-side navigation pane.

   3. In the upper part of the Ingresses page, select the namespace where the inference service resides from the Namespace drop-down list, and click Create Ingress. Set the parameters that are described in the following table. For more information about the parameters, see Create an NGINX Ingress.

      • Name: In this example, the value is set to bert-tfserving.

      • Rule:

        • Domain Name: Enter a custom domain name, such as test.example.com.

        • Mappings

          • Path: The root path / is used in this example.

          • Rule: The default rule (ImplementationSpecific) is used in this example.

          • Service Name: Enter the service name that is returned by the kubectl get service command.

          • Port: In this example, set this parameter to 8501.

7. After you create the Ingress, go to the Ingresses page and find the Ingress. The value in the Rules column contains the endpoint of the Ingress.

8. Use the obtained Ingress address to perform stress tests on the inference service.

9. Log on to AI Dashboard. For more information, see Access AI Dashboard.

   Important

   Before you log on to AI Dashboard, you must install the cloud-native AI suite and specify the access method. For more information, see Deploy the cloud-native AI suite.

10. In the left-side navigation pane of AI Dashboard, choose Elastic Job > Job List. Click the Inference Job tab to view the details about the inference service.

    The following figure shows that all pods created in a scale-out activity run on ECS instances. Both pay-as-you-go and preemptible ECS instances are provisioned. The ratio of pay-as-you-go ECS instances equals the percentage value that you specified when you created the node pool.