Tanzu Mission Control – Attach Clusters

What do you do if you’ve already provisioned some Kubernetes clusters before you got Tanzu Mission Control? Or maybe you’re inheriting some new clusters through an acquisition? Or a new team came on board and were using their own installation? Whatever the case, Tanzu Mission Control will let you manage a conformant Kubernetes cluster but you must first attach it.

Attach An Existing Cluster

For this example, I’ll be attaching a pre-existing Kubernetes cluster on vSphere infrastructure. This cluster was deployed via kubeadm as documented in this previous article about deploying Kubernetes on vSphere.

The first thing we do is find a cluster group where we’ll import the cluster to. On the cluster group screen we’ll click the “ATTACH CLUSTER” button.

After this, the steps are really straightforward and the TMC console will guide you through the process. It should be noted that you’ll need outbound network connectivity to the Internet for the cluster resources to communicate with the Tanzu Mission Control service.

Select the cluster group that this cluster will be added to after the attachment process completes. Then give the cluster a name and description. Lastly, label the cluster according to whatever tagging strategy you’re using within TMC. Then click the “Register” button.

Once this is done, TMC will give you a kubectl command to run which installs the components necessary to mange the cluster. Connect to your existing cluster and run the command to apply the configurations. You can also view the YAML manifests instead if you’d like to see whats being installed before you do it.

I ran the command and several clusterroles, services, secrets, and accounts were created within the VMware-system-tmc namespace.

Once you’ve applied the configuration, click the “VERIFY CONNECTION” button within TMC to complete the process.

After a few minutes of verification, you should see your cluster attached in the TMC console. You can see from my lab that I now have two clusters listed in my cluster group. One of them listed as type “Provisioned” which I deployed from TMC. Another listed as type “Attached” which is the cluster we just attached in this post.