Schedule pods to elastic container instances in an ACK cluster by using virtual nodes - Container Service for Kubernetes

When you need to create many pods quickly within a short time, scaling ECS nodes may be too slow. Reserving extra ECS nodes wastes resources. With ACK virtual nodes, you can schedule pods directly to Elastic Container Instances (ECI) without purchasing or managing ECS nodes. This topic describes how to schedule pods to ECI in an ACK managed cluster.

Scenarios

You can use ECI to handle traffic spikes and reduce computing costs. Typical scenarios include the following:

Online services with clear traffic peaks and troughs
Traffic for online education, e-commerce, and similar services often has clear peaks and troughs. Using ECI-based pods helps you respond faster to traffic spikes and reduces the need to maintain fixed resource pools, which lowers computing costs.
Non-continuous computing tasks
Run computing tasks on ECI-based pods. You do not need to keep fixed nodes. You pay only for the compute resources used during task execution, which lowers computing costs. Examples include Spark and AI tasks.

Prerequisites

Your ACK cluster runs Kubernetes version 1.16 or later. The region where your cluster is located supports ECI.

Note

Check whether your cluster's region is supported. For more information, see Regions and zones supported by ECI. Then log on to the Elastic Container Instance console to activate the ECI service.

Procedure

Step 1: Deploy the ack-virtual-node component

Note

The following steps use an ACK managed cluster as an example. For an ACK dedicated cluster, deploy the ack-virtual-node component from the Marketplace page. For details, see Deploy the ack-virtual-node component.

Log on to the ACK console. In the left navigation pane, click Clusters.
On the Clusters page, find the one you want to manage and click its name. In the left navigation pane, click Add-ons.
On the Component Management page, find ACK Virtual Node in the Core Components section and click Install. Then, complete the operation as prompted.
During the installation, the default virtual switch and security group of the cluster are used as the initial ECI configuration parameters. To modify them, you can update the eci-profile configuration.

Step 2: Schedule pods to elastic container instances

Note

The following steps show how to schedule pods to virtual nodes for running on ECI by adding labels to pods or namespaces. For more scheduling options, see Schedule a pod to a virtual node.

Add a label to a pod

To schedule a specific pod to run on ECI, add the label alibabacloud.com/eci: "true" to the pod. The pod will run on an x86 architecture virtual node as an ECI.

Create a deployment using the following YAML file:

kubectl create -f eci-pod.yaml

The following is an example of eci-pod.yaml:

Note

This YAML uses the k8s.aliyun.com/eci-use-specs annotation to specify the ECI pod specifications. For more information about configuring ECI pod specifications, see Specify the compute specification of an elastic container instance.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: test
  labels:
    app: test
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      name: test
      labels:
        app: nginx
        alibabacloud.com/eci: "true"             # Add this label to schedule the pod to ECI 
      annotations:
        k8s.aliyun.com/eci-use-specs: "2-4Gi"   # Specify 2 vCPUs and 4 GiB of memory for the ECI pod
    spec:
      containers:
      - name: nginx
        image: anolis-registry.cn-zhangjiakou.cr.aliyuncs.com/openanolis/nginx:1.14.1-8.6
        ports:
        - containerPort: 80

Check whether the pod is running on a virtual node.

kubectl get pod -o wide -l app=nginx

The expected output is as follows. In the NODE column, you can see that the pod is scheduled to a virtual node.

NAME                    READY   STATUS    RESTARTS   AGE   IP            NODE                            NOMINATED NODE   READINESS GATES
test-86f7fbc94f-g5m22   1/1     Running   0          38s   10.16.XX.XX   virtual-kubelet-cn-hangzhou-j   <none>           <none>
test-86f7fbc94f-r4wcn   1/1     Running   0          38s   10.16.XX.XX   virtual-kubelet-cn-hangzhou-j   <none>           <none>

View the details of the ECI pod.
```
kubectl get pod <pod-name> -o yaml
```
In the returned YAML, use the k8s.aliyun.com/eci-instance-id field to obtain the ECI instance ID. Use the k8s.aliyun.com/eci-instance-spec field to confirm the actual billing specification of the ECI pod.

Add a label to a namespace

To schedule a group of pods to run on ECI, create a namespace and add the label alibabacloud.com/eci: "true". All pods in this namespace will run on x86 architecture virtual nodes as ECI.

Create a namespace named vk and add the label to it.

kubectl create ns vk
kubectl label namespace vk alibabacloud.com/eci=true

Create a deployment in the vk namespace using the following YAML file:

kubectl create -f eci-namespace.yaml

The following is an example of eci-namespace.yaml:

Note

apiVersion: apps/v1
kind: Deployment
metadata:
  name: test
  namespace: vk       # Specify a namespace with the label to schedule pods to ECI
  labels:
    app: test
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      name: test
      labels:
        app: nginx
      annotations:
        k8s.aliyun.com/eci-use-specs: "2-4Gi"   # Specify 2 vCPUs and 4 GiB of memory for the ECI pod
    spec:
      containers:
      - name: nginx
        image: anolis-registry.cn-zhangjiakou.cr.aliyuncs.com/openanolis/nginx:1.14.1-8.6
        ports:
        - containerPort: 80

Check whether the pod is running on a virtual node.

kubectl get pod -o wide -l app=nginx -n vk

The expected output is as follows. In the NODE column, you can see that the pod is scheduled to a virtual node.

NAME                   READY   STATUS    RESTARTS   AGE   IP            NODE                            NOMINATED NODE   READINESS GATES
test-8f54bcfb5-86pvc   1/1     Running   0          14s   10.16.XX.XX   virtual-kubelet-cn-hangzhou-j   <none>           <none>
test-8f54bcfb5-skvkg   1/1     Running   0          14s   10.16.XX.XX   virtual-kubelet-cn-hangzhou-j   <none>           <none>

View the details of the ECI pod.
```
kubectl get pod <pod-name> -o yaml -n vk
```
In the returned YAML, use the k8s.aliyun.com/eci-instance-id field to obtain the ECI instance ID. Use the k8s.aliyun.com/eci-instance-spec field to confirm the actual billing specification of the ECI pod.