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.
To use the multi-cluster feature using an agent, you must have at least two clusters serving as the host cluster and the member cluster respectively. A cluster can be defined as the host cluster or the member cluster either before or after you install KubeSphere. For more information about installing KubeSphere, refer to Installing on Linux and Installing on Kubernetes.
Video Demonstration
Prepare a Host Cluster
A host cluster provides you with the central control plane and you can only define one host cluster.
If you already have a standalone KubeSphere cluster installed, you can set the value of clusterRole
to host
by editing the cluster configuration.
Option A - Use the web console:
Use the
admin
account to log in to the console and go to CRDs on the Cluster Management page. Enter the keywordClusterConfiguration
and go to its detail page. Edit the YAML ofks-installer
, which is similar to Enable Pluggable Components.Option B - Use Kubectl:
kubectl edit cc ks-installer -n kubesphere-system
In the YAML file of ks-installer
, navigate to multicluster
, set the value of clusterRole
to host
, then click OK (if you use the web console) to make it effective:
multicluster:
clusterRole: host
To set the host cluster name, add a field hostClusterName
under multicluster.clusterRole
in the YAML file of ks-installer
:
multicluster:
clusterRole: host
hostClusterName: <Host cluster name>
Note
- It is recommended that you set the host cluster name while you are preparing your host cluster. When your host cluster is set up and running with resources deployed, it is not recommended that you set the host cluster name.
- The host cluster name can contain only lowercase letters, numbers, hyphens (-), or periods (.), and must start and end with a lowercase letter or number.
You need to wait for a while so that the change can take effect.
You can define a host cluster before you install KubeSphere either on Linux or on an existing Kubernetes cluster. If you want to install KubeSphere on Linux, you use a config-sample.yaml
file. If you want to install KubeSphere on an existing Kubernetes cluster, you use two YAML files, one of which is cluster-configuration.yaml
.
To set a host cluster, change the value of clusterRole
to host
in config-sample.yaml
or cluster-configuration.yaml
accordingly before you install KubeSphere.
multicluster:
clusterRole: host
To set the host cluster name, add a field hostClusterName
under multicluster.clusterRole
in config-sample.yaml
or cluster-configuration.yaml
:
multicluster:
clusterRole: host
hostClusterName: <Host cluster name>
Note
- The host cluster name can contain only lowercase letters, numbers, hyphens (-), or periods (.), and must start and end with a lowercase letter or number.
Info
config-sample.yaml
file. In this case, you can set a host cluster after KubeSphere is installed.You can use kubectl to retrieve the installation logs to verify the status by running the following command. Wait for a while, and you will be able to see the successful log return if the host cluster is ready.
kubectl logs -n kubesphere-system $(kubectl get pod -n kubesphere-system -l 'app in (ks-install, ks-installer)' -o jsonpath='{.items[0].metadata.name}') -f
Set the Proxy Service Address
After the installation of the host cluster, a proxy service called tower
will be created in kubesphere-system
, whose type is LoadBalancer
.
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
Note
Run the following command to check the service:
kubectl -n kubesphere-system get svc
In this sample,
NodePort
is30721
.NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE tower LoadBalancer 10.233.63.191 <pending> 8080:30721/TCP 16h
If
EXTERNAL-IP
ispending
, you need to manually set the proxy address. For example, if your public IP address is139.198.120.120
, you need to expose port (for example,30721
) of this public IP address toNodeIP
:NodePort
.Add the value of
proxyPublishAddress
to the configuration file ofks-installer
and provide the public IP address (139.198.120.120
in this tutorial) and port number as follows.Option A - Use the web console:
Use the
admin
account to log in to the console and go to CRDs on the Cluster Management page. Enter the keywordClusterConfiguration
and go to its detail page. Edit the YAML ofks-installer
, which is similar to Enable Pluggable Components.Option B - Use Kubectl:
kubectl -n kubesphere-system edit clusterconfiguration ks-installer
Navigate to
multicluster
and add a new line forproxyPublishAddress
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.Save the configuration and wait for a while, or you can manually restart
ks-apiserver
to make the change effective immediately using the following command.kubectl -n kubesphere-system rollout restart deployment ks-apiserver
Prepare a Member Cluster
In order to manage the member cluster from the host cluster, you need to make jwtSecret
the same between them. Therefore, get it first by excuting the following command on the host cluster.
kubectl -n kubesphere-system get cm kubesphere-config -o yaml | grep -v "apiVersion" | grep jwtSecret
The output may look like this:
jwtSecret: "gfIwilcc0WjNGKJ5DLeksf2JKfcLgTZU"
If you already have a standalone KubeSphere cluster installed, you can set the value of clusterRole
to member
by editing the cluster configuration.
Option A - Use the web console:
Use the
admin
account to log in to the console and go to CRDs on the Cluster Management page. Enter the keywordClusterConfiguration
and go to its detail page. Edit the YAML ofks-installer
, which is similar to Enable Pluggable Components.Option B - Use Kubectl:
kubectl edit cc ks-installer -n kubesphere-system
In the YAML file of ks-installer
, enter the corresponding jwtSecret
shown above:
authentication:
jwtSecret: gfIwilcc0WjNGKJ5DLeksf2JKfcLgTZU
Scroll down and set the value of clusterRole
to member
, then click OK (if you use the web console) to make it effective:
multicluster:
clusterRole: member
You need to wait for a while so that the change can take effect.
You can define a member cluster before you install KubeSphere either on Linux or on an existing Kubernetes cluster. If you want to install KubeSphere on Linux, you use a config-sample.yaml
file. If you want to install KubeSphere on an existing Kubernetes cluster, you use two YAML files, one of which is cluster-configuration.yaml
. To set a member cluster, enter the value of jwtSecret
shown above and change the value of clusterRole
to member
in config-sample.yaml
or cluster-configuration.yaml
accordingly before you install KubeSphere.
authentication:
jwtSecret: gfIwilcc0WjNGKJ5DLeksf2JKfcLgTZU
multicluster:
clusterRole: member
Note
config-sample.yaml
file. In this case, you can set a member cluster after KubeSphere is installed.You can use kubectl to retrieve the installation logs to verify the status by running the following command. Wait for a while, and you will be able to see the successful log return if the member cluster is ready.
kubectl logs -n kubesphere-system $(kubectl get pod -n kubesphere-system -l 'app in (ks-install, ks-installer)' -o jsonpath='{.items[0].metadata.name}') -f
Import a Member Cluster
Log in to the KubeSphere console as
admin
and click Add Cluster on the Cluster Management page.Enter the basic information of the cluster to be imported on the Import Cluster page. You can also click Edit Mode in the upper-right corner to view and edit the basic information in YAML format. After you finish editing, click Next.
In Connection Method, select Agent connection and click Create. It will show the YAML configuration file for the agent Deployment generated by the host cluster on the console.
Create an
agent.yaml
file on the member cluster based on the instruction, then copy and paste the agent deployment to the file. Executekubectl create -f agent.yaml
on the node and wait for the agent to be up and running. Please make sure the proxy address is accessible to the member cluster.You can see the cluster you have imported in the host cluster when the cluster agent is up and running.
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