A managed edge Kubernetes cluster must contain at least one Elastic Compute Service (ECS) instance. This topic describes how ECS instances work and how to add or remove ECS instances.

Cloud management nodes in edge computing

Cloud management nodes in edge computing
When you create a managed edge cluster, ACK@Edge automatically creates at least one ECS instance as a cloud management node for the cluster. This ECS instance is used to run cloud management applications. You can deploy custom cloud management applications. The taint node-role.alibabacloud.com/addon: Effect: NoSchedule is automatically added to a cloud management node to prevent edge workloads from being scheduled to the node. By default, a management node of version 1.14.8-aliyunedge.1 or earlier has the following management applications:
  • alibaba-log-controller: the Log Service controller.
  • alicloud-monitor-controller: the CloudMonitor controller.
  • metric-server: the server that is used to monitor the cluster.
  • edge-tunnel-server: the server for the reverse O&M tunnel. It allows you to use the native Kubernetes API to access edge nodes, monitor containers, and use SSH to remotely run commands.

Deploy applications to cloud management nodes

If you want to deploy custom management applications on cloud management nodes, for example, to deploy different types of operators, you must specify a toleration that matches the preceding taint and configure node selectors. The following example describes how to set the parameters. 
     ...
      nodeSelector:
        alibabacloud.com/is-edge-worker: 'false'
        beta.kubernetes.io/arch: amd64
        beta.kubernetes.io/os: linux
      tolerations:
        - effect: NoSchedule
          key: node-role.alibabacloud.com/addon
          operator: Exists
      ...

Add a cloud management node

To add a cloud management node, perform the following steps. ACK@Edge will support ECS-based auto scaling in later versions.

  1. Purchase an ECS instance in the virtual private cloud (VPC) where the cluster is deployed.
    For more information about how to purchase an ECS instance, see Create an ECS instance.
    Note Set the operating system to CentOS 7.6.
  2. Call AttachInstances in OpenAPI Explorer to add the ECS instance to the cluster.
    The following example shows a request body:
    {
  "password": "Helloxxxx!",
  "tags":[],
  "instances": [
    "i-uf65mbpn1x8xxxxxx"
  ]
}
    Parameter Description
    password The password that is used to log on to the ECS instance. The password must be 8 to 30 characters in length and must contain at least three of the following character types: uppercase letters, lowercase letters, digits, and special characters.
    tags The tags of the nodes.
    • key: the name of the tag
    • value: the value of the tag.
    instances An array of the existing instances.

    For more information about the API operation, see AttachInstances.