Schedule pods to ECI with Elastic Workload (Deprecated)

Limitations

Elastic Workload does not support OpenKruise workloads. We recommend that you use UnitedDeployment.

Deploy ack-kubernetes-elastic-workload

1. Log on to the Container Service Management Console.

2. In the left navigation pane, choose Marketplace > Marketplace.

3. On the Marketplace page, click the App Catalog tab, and then select the ack-kubernetes-elastic-workload application.

4. On the ack-kubernetes-elastic-workload page, click Deploy.

5. In the Deploy panel, select a cluster and namespace, and then click Next.

6. On the Parameters page, configure the parameters, and then click OK.

   After the deployment is complete, the ack-kubernetes-elastic-workload application appears under Applications > Helm in the left-side navigation pane of the cluster management page.

Use Elastic Workload

This example demonstrates an application with the following capacity planning requirements: a maximum of four replicas run on ECS instances, with two replicas maintained during off-peak hours. When the replica count exceeds four, the workload scales out to virtual nodes to avoid interfering with other applications that have fixed capacity plans.

In Kubernetes, workload management involves two main aspects: scheduling and lifecycle management. Implementing this scenario requires addressing the following questions:

• How to change the scheduling policy when the number of replicas reaches a certain threshold.

• How to prioritize certain pods during lifecycle management.

The following procedure shows how to use Elastic Workload to address this scenario.

1. Create a simple Deployment.

   apiVersion: apps/v1 # for versions before 1.8.0 use apps/v1beta1
   kind: Deployment
   metadata:
     name: nginx-deployment-basic
     labels:
       app: nginx
   spec:
     replicas: 2
     selector:
       matchLabels:
         app: nginx
     template:
       metadata:
         labels:
           app: nginx
       spec:
       #  nodeSelector:
       #    env: test-team
         containers:
         - name: nginx
           image: anolis-registry.cn-zhangjiakou.cr.aliyuncs.com/openanolis/nginx:1.14.1-8.6
           ports:
           - containerPort: 80
           resources:
             limits:
               cpu: "500m"

2. Define an ElasticWorkload resource.

   apiVersion: autoscaling.alibabacloud.com/v1beta1
   kind: ElasticWorkload
   metadata:
     name: elasticworkload-sample
   spec:
     sourceTarget:
       name: nginx-deployment-basic
       kind: Deployment
       apiVersion: apps/v1
       min: 2        # The minimum number of replicas.
       max: 4        # The maximum number of replicas.
     replicas: 6
     elasticUnit:
     - name: virtual-kubelet
       labels:
         alibabacloud.com/eci: "true"

   An ElasticWorkload resource is similar to a Horizontal Pod Autoscaler (HPA). It is applied externally and does not affect your original application.

   

   A typical ElasticWorkload resource consists of two main parts:

   • The sourceTarget section defines the type of the source workload and its scalable replica range.

   • The elasticUnit section is an array that defines the scheduling policy for the elastic units. If you have multiple elastic units, Elastic Workload processes them in their defined order.

   In this example:

   • The sourceTarget section defines a replica range of 2 to 4. When the replicas count in the ElasticWorkload is between 2 and 4, pods are scheduled to the sourceTarget. When the count exceeds 4, the extra pods are scheduled to the elastic unit, which is the virtual-kubelet virtual node.

   • The elasticUnit section defines the elastic unit as the virtual-kubelet virtual node. The scheduling policy is specified by the label alibabacloud.com/eci: "true".

3. Verify the deployment.

   • Check the current status.

     kubectl describe ew elasticworkload-sample   # same as kubectl get elasticworkload

     The command returns the following output. In the Status section, Desired Replicas for each unit indicates the number of replicas allocated by the ElasticWorkload.

     Name:         elasticworkload-sample
     Namespace:    default
     Labels:       <none>
     Annotations:  <none>
     API Version:  autoscaling.alibabacloud.com/v1beta1
     Kind:         ElasticWorkload
     Metadata:
       Creation Timestamp:  2021-05-21T01:53:58Z
       Generation:          4
       Managed Fields:
         API Version:  autoscaling.alibabacloud.com/v1beta1
         Fields Type:  FieldsV1
         fieldsV1:
           f:spec:
             .:
             f:elasticUnit:
             f:replicas:
             f:sourceTarget:
               .:
               f:apiVersion:
               f:kind:
               f:max:
               f:min:
               f:name:
         Manager:      Apache-HttpClient
         Operation:    Update
         Time:         2021-05-21T01:53:58Z
         API Version:  autoscaling.alibabacloud.com/v1beta1
         Fields Type:  FieldsV1
         fieldsV1:
           f:status:
             .:
             f:elasticUnitsStatus:
             f:replicas:
             f:selector:
             f:sourceTarget:
               .:
               f:apiVersion:
               f:desiredReplicas:
               f:kind:
               f:name:
               f:updateTimestamp:
         Manager:         manager
         Operation:       Update
         Time:            2021-05-21T01:56:45Z
       Resource Version:  8727
       Self Link:         /apis/autoscaling.alibabacloud.com/v1beta1/namespaces/default/elasticworkloads/elasticworkload-sample
       UID:               c4a508aa-2702-4d17-ac25-e6a207c0761a
     Spec:
       Elastic Unit:
         Labels:
           alibabacloud.com/eci:  true
         Name:                    virtual-kubelet
       Replicas:                  6
       Source Target:
         API Version:  apps/v1
         Kind:         Deployment
         Max:          4
         Min:          2
         Name:         nginx-deployment-basic
     Status:
       Elastic Units Status:
         Desired Replicas:  2
         Name:              nginx-deployment-basic-unit-virtual-kubelet
         Update Timestamp:  2021-05-21T01:56:45Z
       Replicas:            6
       Selector:            app=nginx
       Source Target:
         API Version:       apps/v1
         Desired Replicas:  4
         Kind:              Deployment
         Name:              nginx-deployment-basic
         Update Timestamp:  2021-05-21T01:56:45Z
     Events:
       Type    Reason                 Age                  From             Message
       ----    ------                 ----                 ----             -------
       Normal  SourceUpdate           12m                  ElasticWorkload  Source Target scale from 2 to 4
       Normal  UnitCreation           12m                  ElasticWorkload  ElasticWorkloadUnit nginx-deployment-basic-unit-virtual-kubelet created
       Normal  ElasticWorkloadUpdate  9m27s (x9 over 12m)  ElasticWorkload  ElasticWorkload update
       Normal  UnitUpdate             9m27s (x8 over 12m)  ElasticWorkload  ElasticWorkloadUnit virtual-kubelet has been updated

   • Check the pod status.

     kubectl get pod -o wide

     The command returns the following output. This output shows that Elastic Workload cloned a new Deployment and its pods, and dynamically allocated the replicas according to the scheduling policy.

     NAME                                                           READY   STATUS    RESTARTS   AGE   IP              NODE                           NOMINATED NODE   READINESS GATES
     nginx-deployment-basic-5bf87f5f59-22jnw                        1/1     Running   0          16m   10.34.0.131     cn-beijing.172.16.0.1          <none>           <none>
     nginx-deployment-basic-5bf87f5f59-gfp24                        1/1     Running   0          13m   10.34.0.133     cn-beijing.172.16.0.1          <none>           <none>
     nginx-deployment-basic-5bf87f5f59-pw2zx                        1/1     Running   0          13m   10.34.0.134     cn-beijing.172.16.0.1          <none>           <none>
     nginx-deployment-basic-5bf87f5f59-qvh7m                        1/1     Running   0          16m   10.34.0.132     cn-beijing.172.16.0.1          <none>           <none>
     nginx-deployment-basic-unit-virtual-kubelet-65fb6f4cd7-48ssb   1/1     Running   0          13m   172.16.22.157   virtual-kubelet-cn-beijing-e   <none>           <none>
     nginx-deployment-basic-unit-virtual-kubelet-65fb6f4cd7-gjqhm   1/1     Running   0          13m   172.16.22.158   virtual-kubelet-cn-beijing-e   <none>           <none>

apiVersion: autoscaling/v2beta2
kind: HorizontalPodAutoscaler
metadata:
  name: elastic-workload-demo
  namespace: default
spec:
  scaleTargetRef:
    apiVersion: autoscaling.alibabacloud.com/v1beta1
    kind: ElasticWorkload
    name: elasticworkload-sample
  minReplicas: 2
  maxReplicas: 10
  metrics:
  - type: Resource
    resource:
      name: cpu
      target:
        type: Utilization
        averageUtilization: 50