Deploy in High Availability

By default, vCluster runs one instance of each of its components. This deployment method is recommended for any uses cases that are very ephemeral (e.g. dev environments, CI/CD, etc.), but for most production use cases, you will want to run vCluster with more redundancy. We recommend deploying vCluster in High Availability (HA) mode to run multiple copies of the vCluster components so that the virtual cluster is more resistant to partial failures.

Create the HA virtual cluster

To create a vCluster using the vCluster CLI, we run the vcluster create command. To enable HA, we’ll need to specify the distro and the vcluster.yaml file to use:

controlPlane:
  # Use an external etcd for vCluster
  backingStore:
    etcd:
      deploy:
        enabled: true
        statefulSet:
          highAvailability:
            replicas: 3
  # Deploy vCluster with 3 replicas
  statefulSet:
    highAvailability:
      replicas: 3

vcluster create ha-tutorial --connect=false -f vcluster.yaml

We’ve named the vCluster ha-tutorial. By default, the vcluster create command connects to the vCluster after creation, but for the purposes of this tutorial, we’ve disabled this automatic connection by adding in the --connect=false flag.

You should see output like this:

info   Creating namespace vcluster-ha-tutorial
...
- Use 'vcluster connect ha-tutorial --namespace vcluster-ha-tutorial' to access the vCluster 

note

Some of your output may differ depending on whether you use a local or remote cluster.

As you can see, the creation of a vCluster has created a namespace called vcluster-ha-tutorial in the host cluster, and the components of the vCluster lives inside this namespace. Next, let’s see what pods are running in that namespace.

kubectl get pods -n vcluster-ha-tutorial

NAME                                      READY   STATUS    RESTARTS   AGE
ha-tutorial-7c5c5844c5-27j2v              0/1     Running   0          20s
ha-tutorial-7c5c5844c5-gb2sm              0/1     Running   0          20s
ha-tutorial-7c5c5844c5-pwn7k              0/1     Running   0          20s
ha-tutorial-etcd-0                        0/1     Running   0          20s
ha-tutorial-etcd-1                        0/1     Running   0          20s
ha-tutorial-etcd-2                        0/1     Running   0          20s

There are now three replicas of each component of the vCluster running. If one API server pod went down, the vCluster would continue functioning.

If you’d like more information about how the pods were scheduled in the vCluster, add the -o wide flag to the kubectl get pods command:

kubectl get pods -n vcluster-ha-tutorial -o wide

The hostnames of the nodes will be listed in the NODES column.

Connect to vCluster

We can connect to the vCluster using the vcluster connect command.

vcluster connect ha-tutorial

info   Starting proxy container...
done √ Switched active kube context to vcluster_ha-tutorial_vcluster-ha-tutorial_minikube
- Use `vcluster disconnect` to return to your previous kube context
- Use `kubectl get namespaces` to access the vcluster

vcluster connect automatically switches our kube context for kubectl to the vCluster. Now, we can list the namespaces inside of the vCluster by running this command:

kubectl get namespaces
Copy
NAME              STATUS   AGE
default           Active   31s
kube-node-lease   Active   33s
kube-public       Active   33s
kube-system       Active   33s

Our vCluster only contains the default namespaces that were created by Kubernetes.

Now let’s disconnect from the vCluster.

vcluster disconnect

This will switch your kube context back to the host cluster.

Cleanup

One of the great things about running vCluster is that it’s very fast and easy to clean up all the components of the vCluster when you’re done using them.

vcluster delete ha-tutorial

That will delete all components of the vCluster and the namespace it was in.

Create the HA virtual cluster​

Connect to vCluster

Cleanup

Create the HA virtual cluster