tower

README

KubeSphere Multi-Cluster Agent Connection

The component Tower of KubeSphere is used for agent connection. Tower is a tool for network connection between clusters through the agent. If the host cluster cannot access the member cluster directly, you can expose the proxy service address of the host cluster. This enables the member cluster to connect to the host cluster through the agent. This method is applicable when the member cluster is in a private environment (for example, IDC) and the host cluster is able to expose the proxy service. The agent connection is also applicable when your clusters are distributed across different cloud providers.

Set the Proxy Service Address

After the installation of the tower extension, a proxy service called tower will be created in kubesphere-system, whose type is LoadBalancer.

A LoadBalancer available in your cluster

If a LoadBalancer plugin is available for the cluster, you can see a corresponding address for EXTERNAL-IP of tower, which will be acquired by KubeSphere. In this case, the proxy service is set automatically. That means you can skip the step to set the proxy. Execute the following command to verify if you have a LoadBalancer.

kubectl -n kubesphere-system get svc

The output is similar to this:

NAME       TYPE            CLUSTER-IP      EXTERNAL-IP     PORT(S)              AGE
tower      LoadBalancer    10.233.63.191   139.198.110.23  8080:30721/TCP       16h

Generally, there is always a LoadBalancer solution in the public cloud, and the external IP can be allocated by the load balancer automatically. If your clusters are running in an on-premises environment, especially a bare metal environment, you can use OpenELB as the LB solution.

No LoadBalancer available in your cluster

1. Run the following command to check the service:

   kubectl -n kubesphere-system get svc
   

   In this sample, NodePort is 30721.

   NAME       TYPE            CLUSTER-IP      EXTERNAL-IP     PORT(S)              AGE
   tower      LoadBalancer    10.233.63.191   <pending>       8080:30721/TCP       16h
   

2. If EXTERNAL-IP is pending, you need to manually set the proxy address. For example, if your public IP address is 139.198.120.120, you need to expose port (for example, 30721) of this public IP address to NodeIP:NodePort.

3. Add the value of proxyPublishAddress to the kubesphere-config ConfigMap and provide the public IP address (139.198.120.120 in this tutorial) and port number as follows.

   kubectl -n kubesphere-system edit cm kubesphere-config
   

   Navigate to multicluster and add a new line for proxyPublishAddress to define the IP address to access tower.

   multicluster:
     clusterRole: host
     proxyPublishAddress: http://139.198.120.120:{NodePort} # Add this line to set the address to access tower
   

   In the YAML file, you need to replace NodePort with the port ID you specified in Step 2.

Custom agent image

By default, you do not need to set it. If there are some special scenarios where you need to configure the image used by the agent, you can set the agentImage field in the kubesphere-config ConfigMap:

multicluster:
  clusterRole: host
  proxyPublishAddress: ...
  agentImage: kubesphere/tower:v0.2.1