OpenStack Hosted Control Plane Deployment#

Follow these steps to set up a k0smotron-hosted control plane on OpenStack:

Prerequisites

Before proceeding, make sure you have the following:
- A management Kubernetes cluster (Kubernetes v1.28 or later) deployed on OpenStack with k0rdent installed.
- An OpenStack Cloud Controller Manager installed to manage Services with the Load Balancer type.
- A default storage class configured on the management cluster to support Persistent Volumes.
- An OpenStack Credential object and resource-template ConfigMap must exist in the namespace where the cluster will be deployed. Refer to steps 4–6 in the OpenStack management cluster preparation guide.
- The name of the existing network and subnet where the worker nodes will be deployed.
- The name of the existing router that will be used to deploy the worker nodes.
- (Optional) The name of the existing security group to attach to the worker nodes.
Important

All control plane components for your hosted cluster will reside in the management cluster, and the management cluster must have sufficient resources to handle these additional workloads.
Networking

To deploy a hosted control plane, the necessary OpenStack networking resources must already exist or be created. If you're using the same network, subnet and router as your management cluster, you can reuse these resources.

If your management cluster was deployed using the Cluster API Provider OpenStack (CAPO), you can gather the required networking details using the following commands:

Retrieve the network name:
```
kubectl -n <cluster-namespace> get openstackcluster <cluster-name> -o go-template='{{.status.network.name}}'
```
Retrieve the subnet name:
```
kubectl -n <cluster-namespace> get openstackcluster <cluster-name> -o go-template='{{(index .status.network.subnets 0).name}}'
```
Retrieve the router name:
```
kubectl -n <cluster-namespace> get openstackcluster <cluster-name> -o go-template='{{.status.router.name}}'
```

Create the ClusterDeployment manifest

Once you've collected all the necessary data, you can create the ClusterDeployment manifest. This file tells k0rdent how to deploy and manage the hosted control plane. For example:

apiVersion: k0rdent.mirantis.com/v1beta1
kind: ClusterDeployment
metadata:
  name: openstack-hosted-cp
spec:
  template: openstack-hosted-cp-1-0-0
  credential: openstack-credential
config:
  workersNumber: 2
  flavor: m1.medium
  image:
    filter:
      name: ubuntu-20.04
  externalNetwork:
    filter:
      name: "public"
  identityRef:
    name: "openstack-cloud-config"
    cloudName: "openstack"
    region: ${OS_REGION_NAME}

  network:
    filter:
      name: ${NETWORK_NAME}
  router:
    filter:
      name: ${ROUTER_NAME}
  subnets:
  - filter:
      name: ${SUBNET_NAME}
  ports:
  - network:
      filter:
        name: ${NETWORK_NAME}

Note

When deploying clusters with openstack-hosted-cp template version 1-0-2 or newer, the identityRef.name parameter is ignored and can be omitted. For older template versions, this parameter is required and must match the name of the Secret containing the clouds.yaml configuration.

You can adjust flavor, image name, region name, network, subnet and router configuration to match your OpenStack environment. For more information about the configuration options, see the Template reference for openstack

Alternatively, you can generate the ClusterDeployment manifest.

To simplify the creation of a ClusterDeployment manifest, you can use the following template, which dynamically inserts the appropriate values:

apiVersion: k0rdent.mirantis.com/v1beta1
kind: ClusterDeployment
metadata:
  name: openstack-hosted
spec:
  template: openstack-hosted-cp-1-0-0
  credential: openstack-credential
  config:
    workersNumber: 2
    flavor: m1.medium
    image:
      filter:
        name: ubuntu-20.04
    externalNetwork:
      filter:
        name: "public"
    identityRef:
      name: "openstack-cloud-config"
      cloudName: "openstack"
      region: "{{.spec.identityRef.region}}"

    network:
      filter:
        name: "{{.status.network.name}}"
    router:
      filter:
        name: "{{.status.router.name}}"
    subnets:
    - filter:
        name: "{{(index .status.network.subnets 0).name}}"
    ports:
    - network:
        filter:
          name: "{{.status.network.name}}"

For more information on these and other available parameters, see the Template reference for openstack.

Save this template as clusterdeployment.yaml.tpl, then generate your manifest using the following command:

kubectl -n <cluster-namespace> get openstackcluster <cluster-name> -o go-template="$(cat clusterdeployment.yaml.tpl)" > clusterdeployment.yaml

Apply the template

Nothing actually happens until you apply the ClusterDeployment manifest to create a new cluster deployment:
```
kubectl apply -f clusterdeployment.yaml -n kcm-system
```