Schedule pods to a VNode - Elastic Container Instance - Alibaba Cloud Documentation Center

If you have self-managed Kubernetes clusters in a data center or on an Alibaba Cloud Elastic Compute Service (ECS) instance, you use both real nodes and virtual nodes (VNodes). In this case, you can configure the nodeSelector and tolerations fields, or specify the nodeName field to schedule pods to VNodes. Then, you can run the pods as elastic container instances. This topic describes how to schedule pods to a VNode.

Overview of scheduling methods

VNodes are equivalent to native Kubernetes nodes. If a Kubernetes cluster uses both real nodes and VNodes, you can use one of the following methods to schedule pods to a VNode:

Note

To use the following methods, you must modify existing resources. These modifications may cause vulnerabilities in your system. We recommend that you deploy the eci-profile component. eci-profile allows you to configure the selector field to have pods that meet the conditions specified by the selector field automatically scheduled to VNodes. For more information, see Use eci-profile to schedule pods to a VNode.

Configure the nodeSelector and tolerations fields
By default, VNodes are configured with labels and taints. Therefore, you can configure nodeSelector and tolerations to schedule pods to VNodes and then run the pods as elastic container instances.
Specify the nodeName field
You can specify the nodeName field to schedule pods to the specified VNode and then run the pods as elastic container instances.

Method 1: Configure the nodeSelector and tolerations fields

By default, VNodes are configured with labels and taints, as shown in the following code.

...
  labels:
    k8s.aliyun.com/vnode: "true"
...
  taints:
  - effect: NoSchedule
    key: k8s.aliyun.com/vnode
    value: "true"

Therefore, you can configure the nodeSelector and tolerations fields to schedule pods to VNodes and then run the pods as elastic container instances. Perform the following operations:

Save the following content as the deploy-vnode-test1.yaml file.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: vnode-nginx-test1
spec:
  replicas: 2
  selector:
    matchLabels:
      app: uid
  template:
    metadata:
      labels:
        app: uid
    spec:
      nodeSelector:     # Configure nodeSelector.
        k8s.aliyun.com/vnode: "true"
      tolerations:      # Configure tolerations.
      - key: k8s.aliyun.com/vnode
        operator: "Equal"
        value: "true"
        effect: "NoSchedule"
      containers:
      - name: nginx
        image: registry-vpc.cn-hangzhou.aliyuncs.com/eci_open/nginx:1.14.2

Create a Deployment.

kubectl apply -f deploy-vnode-test1.yaml

Method 2: Specify the nodeName field

You can specify the nodeName field to schedule pods to VNodes. Perform the following operations:

Run the following command to query VNodes.

kubectl get nodes

Obtain the name of the VNode from the command output. By default, the name format of a VNode is <region>.<VNode ID>. Sample output:

NAME                                    STATUS   ROLES                  AGE    VERSION
cn-hangzhou.vnd-2ze2qhf8lmp5kgsx****    Ready    agent                  132m   v1.20.6
k8s-master                              Ready    control-plane,master   169m   v1.20.6

Save the following content as the deploy-vnode-test2.yaml file.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: vnode-nginx-test2
spec:
  replicas: 2
  selector:
    matchLabels:
      app: uid
  template:
    metadata:
      labels:
        app: uid
    spec:
      containers:
      - name: nginx
        image: registry-vpc.cn-hangzhou.aliyuncs.com/eci_open/nginx:1.14.2
      nodeName: cn-hangzhou.vnd-2ze2qhf8lmp5kgsx****   # Specify the name of the VNode.

Create a Deployment.

kubectl apply -f deploy-vnode-test2.yaml