Minimal Environment

This guide walks you through deploying the smallest viable CobaltCore environment: one control plane node running the Kubernetes control plane and OpenStack services, and one hypervisor node running KVM virtual machines.

This is not a production configuration - it has no high availability and no redundant storage. It is suitable for exploration, development, and learning how the components fit together.

What you will deploy

┌─────────────────────────────────┐
│  Control Plane Node             │
│  Kubernetes · OpenStack (Helm)  │
│  Ceph (single node)             │
└──────────────┬──────────────────┘
               │
┌──────────────▼──────────────────┐
│  Hypervisor Node                │
│  GardenLinux · KVM · libvirt    │
│  Hypervisor Operator agents     │
└─────────────────────────────────┘

Prerequisites

• Two machines (physical or virtual), each with:
  • 8+ CPUs, 32 GB RAM, 200 GB disk
  • Linux OS (Ubuntu 22.04 or equivalent)
  • Network connectivity between them
• kubectl installed on your workstation
• helm v3 installed
• Basic familiarity with Kubernetes

Step 1: Bootstrap the Kubernetes cluster

CobaltCore uses Gardener for cluster lifecycle management in production, but for a minimal setup you can use any conformant Kubernetes distribution (k3s, kubeadm, kind with enough resources).

The control plane must be reachable from the hypervisor node.

Step 2: Install the Hypervisor Operator

The Hypervisor Operator manages hypervisor node lifecycle. Install it into your cluster:

helm repo add cobaltcore https://cobaltcore-dev.github.io/charts
helm repo update
helm install hypervisor-operator cobaltcore/hypervisor-operator \
  --namespace cobaltcore-system \
  --create-namespace

See Compute - Hypervisor for configuration options.

Step 3: Register the hypervisor node

Create a Hypervisor resource to register your compute node:

apiVersion: kvm.cloud.sap/v1
kind: Hypervisor
metadata:
  name: hypervisor-01
spec:
  lifecycleEnabled: true
  highAvailability: false
  version: latest

Apply it and verify the node is discovered:

kubectl apply -f hypervisor.yaml
kubectl get hypervisors

Step 4: Deploy storage (single-node Ceph)

For a minimal setup, deploy Ceph in single-replica mode via Rook:

helm repo add rook-release https://charts.rook.io/release
helm repo update

helm install rook-ceph rook-release/rook-ceph \
  --namespace rook-ceph \
  --create-namespace \
  --version v1.20.7 \
  --wait

helm repo add ceph-csi-operator https://ceph.github.io/ceph-csi-operator
helm repo update
helm install ceph-csi-drivers ceph-csi-operator/ceph-csi-drivers \
  --namespace rook-ceph \
  --version 1.0.4 \
  --wait \
  -f https://raw.githubusercontent.com/rook/rook/v1.20.7/deploy/charts/ceph-csi-drivers/values.yaml

Create minimal-ceph-cluster.yaml, replacing k3s-node and sdb with the Kubernetes node name and the dedicated raw device in your lab:

apiVersion: ceph.rook.io/v1
kind: CephCluster
metadata:
  name: rook-ceph
  namespace: rook-ceph
spec:
  dataDirHostPath: /var/lib/rook
  cephVersion:
    image: quay.io/ceph/ceph:v20.2.4
  mon:
    count: 1
    allowMultiplePerNode: true
  mgr:
    count: 1
    allowMultiplePerNode: true
  storage:
    useAllNodes: false
    useAllDevices: false
    nodes:
    - name: k3s-node
      devices:
      - name: sdb
  cephConfig:
    global:
      osd_pool_default_size: "1"
      mon_warn_on_pool_no_redundancy: "false"
---
apiVersion: ceph.rook.io/v1
kind: CephBlockPool
metadata:
  name: replicapool
  namespace: rook-ceph
spec:
  replicated:
    size: 1
    requireSafeReplicaSize: false
---
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: rook-ceph-block
provisioner: rook-ceph.rbd.csi.ceph.com
parameters:
  clusterID: rook-ceph
  pool: replicapool
  imageFormat: "2"
  imageFeatures: layering
  csi.storage.k8s.io/provisioner-secret-name: rook-csi-rbd-provisioner
  csi.storage.k8s.io/provisioner-secret-namespace: rook-ceph
  csi.storage.k8s.io/controller-expand-secret-name: rook-csi-rbd-provisioner
  csi.storage.k8s.io/controller-expand-secret-namespace: rook-ceph
  csi.storage.k8s.io/controller-publish-secret-name: rook-csi-rbd-provisioner
  csi.storage.k8s.io/controller-publish-secret-namespace: rook-ceph
  csi.storage.k8s.io/node-stage-secret-name: rook-csi-rbd-node
  csi.storage.k8s.io/node-stage-secret-namespace: rook-ceph
  csi.storage.k8s.io/fstype: ext4
allowVolumeExpansion: true
reclaimPolicy: Delete

The device must be unformatted, unmounted, and dedicated to this disposable test cluster. Apply the manifest and wait for Ceph to become ready:

kubectl apply -f minimal-ceph-cluster.yaml
kubectl -n rook-ceph wait --for=condition=Ready cephcluster/rook-ceph --timeout=15m

This single-node configuration is for testing only. See Storage - Rook for the production three-node cluster configuration.

Step 5: Deploy OpenStack

OpenStack services are deployed via Helm. A minimal configuration enables Nova, Neutron, Cinder, Keystone, and Glance:

helm install openstack cobaltcore/openstack \
  --namespace openstack \
  --create-namespace \
  --values minimal-values.yaml

See OpenStack for service-level configuration.

Step 6: Verify

Check that all components are running:

kubectl get pods -n cobaltcore-system
kubectl get pods -n rook-ceph
kubectl get pods -n openstack
kubectl get hypervisors

Access the OpenStack API endpoint and create a test VM to confirm end-to-end functionality.

Next steps

• Full production deployment - add HA, stretched storage, and the management frontend
• Compute - Hypervisor - configure hypervisor agents and HA
• Storage - Ceph - tune storage pools and replication
• OpenStack - configure individual services