Scaling Controller Nodes in a Worker Cluster¶

This article provides a step-by-step guide on how to manually scale the control nodes in a worker cluster to achieve high availability for self-built clusters.

Prerequisites¶

• A worker cluster has been created using the DCE 5.0 platform. You can refer to the documentation on Creating a Worker Cluster.
• The managed cluster associated with the worker cluster exists in the current platform and is running normally.

Modify the Host manifest¶

1. Log in to the container management platform and go to the overview page of the cluster where you want to scale the control nodes. In the Basic Information section, locate the Managed Cluster of the current cluster and click its name to enter the overview page.

2. In the overview page of the managed cluster, click Console to open the cloud terminal console. Run the following command to find the host manifest of the worker cluster that needs to be scaled.

   kubectl get cm -n kubean-system ${ClusterName}-hosts-conf -oyaml
   

   ${ClusterName} is the name of the worker cluster to be scaled.

3. Modify the host manifest file based on the example below and add information for the controller nodes.

   Before ModificationAfter Modification

   apiVersion: v1
   kind: ConfigMap
   metadata:
     name: tanghai-dev-hosts-conf
     namespace: kubean-system
   data:
     hosts.yml: |
       all:
         hosts:
           node1:
             ip: 10.6.175.10 
             access_ip: 10.6.175.10
             ansible_host: 10.6.175.10 
             ansible_connection: ssh
             ansible_user: root
             ansible_password: password01
         children:
           kube_control_plane:
             hosts:
               node1:
           kube_node:
             hosts:
               node1:
           etcd:
             hosts:
               node1:
           k8s_cluster:
             children:
               kube_control_plane:
               kube_node:
           calico_rr:
             hosts: {}
   ......
   

   apiVersion: v1
   kind: ConfigMap
   metadata:
     name: tanghai-dev-hosts-conf
     namespace: kubean-system
   data:
     hosts.yml: |
       all:
         hosts:
           node1:
             ip: 10.6.175.10
             access_ip: 10.6.175.10 
             ansible_host: 10.6.175.10
             ansible_connection: ssh
             ansible_user: root
             ansible_password: password01
           node2: # Add controller node2
             ip: 10.6.175.20
             access_ip: 10.6.175.20
             ansible_host: 10.6.175.20
             ansible_connection: ssh
             ansible_user: root
             ansible_password: password01
           node3:
             ip: 10.6.175.30 
             access_ip: 10.6.175.30
             ansible_host: 10.6.175.30 
             ansible_connection: ssh
             ansible_user: root
             ansible_password: password01
         children:
           kube_control_plane:
             hosts:
               node1:
               node2: # Add controller node2
               node3: # Add controller node3
           kube_node:
             hosts:
               node1:
               node2: # Add controller node2
               node3: # Add controller node3
           etcd:
             hosts:
               node1:
               node2: # Add controller node2
               node3: # Add controller node3
           k8s_cluster:
             children:
               kube_control_plane:
               kube_node:
           calico_rr:
             hosts: {}
   

Important Parameters:

• all.hosts.node1: Existing master node in the original cluster
• all.hosts.node2, all.hosts.node3: Control nodes to be added during cluster scaling
• all.children.kube_control_plane.hosts: Control plane group in the cluster
• all.children.kube_node.hosts: Worker node group in the cluster
• all.children.etcd.hosts: ETCD node group in the cluster

Add Expansion Task "scale-master-node-ops.yaml" using the ClusterOperation.yml Template¶

Use the following ClusterOperation.yml template to add a cluster control node expansion task called "scale-master-node-ops.yaml".

apiVersion: kubean.io/v1alpha1
kind: ClusterOperation
metadata:
  name: cluster1-online-install-ops
spec:
  cluster: ${cluster-name} # Specify cluster name
  image: ghcr.m.daocloud.io/kubean-io/spray-job:v0.18.0 # Specify the image for the kubean job
  actionType: playbook
  action: cluster.yml
  extraArgs: --limit=etcd,kube_control_plane -e ignore_assert_errors=yes
  preHook:
    - actionType: playbook
      action: ping.yml
    - actionType: playbook
      action: disable-firewalld.yml
    - actionType: playbook
      action: enable-repo.yml  # In an offline environment, you need to add this yaml and
      # set the correct repo-list (for installing operating system packages).
      # The following parameter values are for reference only.
      extraArgs: |
        -e "{repo_list: ['http://172.30.41.0:9000/kubean/centos/\$releasever/os/\$basearch','http://172.30.41.0:9000/kubean/centos-iso/\$releasever/os/\$basearch']}"
  postHook:
    - actionType: playbook
      action: upgrade-cluster.yml
      extraArgs: --limit=etcd,kube_control_plane -e ignore_assert_errors=yes
    - actionType: playbook
      action: kubeconfig.yml
    - actionType: playbook
      action: cluster-info.yml

Create and deploy scale-master-node-ops.yaml based on the above configuration.

# Copy the above manifest
vi scale-master-node-ops.yaml
kubectl apply -f scale-master-node-ops.yaml -n kubean-system

Perform the following command to verify it.

kubectl get node

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