External Infrastructure

By default, the HyperShift operator hosts both the HostedCluster's control plane pods and KubeVirt worker VMs within the same cluster.

With the external infrastructure feature, it possible to place the worker node VMs on a separate cluster from the control plane pods.

Understanding Hosting Cluster Types

Management Cluster: This is the OpenShift cluster that runs the HyperShift operator and hosts the control plane pods for a HostedCluster.

Infrastructure Cluster: This is the OpenShift cluster that runs the KubeVirt worker VMs for a HostedCluster.

By default, the management cluster also acts as the infrastructure cluster that hosts VMs. However, for the external infrastructure use case, the management and infrastructure clusters are distinctly different.

Create a HostedCluster using External Infrastructure

Prerequisites * Creation of a namespace on the external infrastructure cluster for the KubeVirt worker nodes to be hosted in. * A kubeconfig for the external infrastructure cluster

Once the prerequisites are met, the hcp cli tool can be used to create the guest cluster. In order to place the KubeVirt worker VMs on the infrastructure cluster, use the --infra-kubeconfig-file and --infra-namespace arguments.

Below is an example of creating a guest cluster using external infrastructure.

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export CLUSTER_NAME=example
export PULL_SECRET="$HOME/pull-secret"
export MEM="6Gi"
export CPU="2"
export WORKER_COUNT="2"

hcp create cluster kubevirt \
--name $CLUSTER_NAME \
--node-pool-replicas $WORKER_COUNT \
--pull-secret $PULL_SECRET \
--memory $MEM \
--cores $CPU \
--infra-namespace=clusters-example \
--infra-kubeconfig-file=$HOME/external-infra-kubeconfig

This command will result in the control plane pods being hosted on the management cluster that the HyperShift Operator runs on, while the KubeVirt VMs will be hosted on a separate infrastructure cluster.