Hypershift Kubevirt Provider

Network Conflict Prevention (CRITICAL)

The most important aspect of KubeVirt clusters is preventing network conflicts:

• Service/Cluster/Machine CIDRs must not overlap with management cluster
• Default CIDRs are designed to avoid common management cluster ranges
• Always check management cluster CIDRs before setting HostedCluster CIDRs

Common management cluster ranges to avoid:

• 10.128.0.0/14 (common OCP default)
• 10.0.0.0/16 (common private range)
• 192.168.0.0/16 (common private range)

Implementation Steps

Step 1: Analyze Cluster Description

Parse the natural language description for KubeVirt-specific requirements:

Environment Type Detection:

• Development: "dev", "development", "testing", "lab", "demo"
• Production: "prod", "production", "critical", "enterprise"
• Disconnected: "airgapped", "disconnected", "offline", "air-gapped"

Resource Indicators:

• High Performance: "performance", "fast", "high-compute", "intensive"
• Standard: Default moderate configuration
• Minimal: "small", "minimal", "basic", "edge"

Network Requirements:

• IPv6: "ipv6", "dual-stack", "ipv6-only"
• Isolated: "isolated", "private", "secure"

Storage Requirements:

• Local Storage: "local", "local storage", "hostpath"
• Replicated: "replicated", "distributed", "ceph", "longhorn"

Step 2: Management Cluster Network Discovery

CRITICAL FIRST STEP: Always check management cluster networks to prevent conflicts.

Prompt for management cluster information:

🔹 **Management Cluster Networks**: To avoid conflicts, please run this command on your management cluster:

   `oc get network cluster -o yaml`

   From the output, what are the serviceNetwork and clusterNetwork CIDRs?
   - serviceNetwork CIDR: [e.g., 172.30.0.0/16]
   - clusterNetwork CIDR: [e.g., 10.128.0.0/14]
   - [Press Enter if you don't know - I'll use safe defaults]

If user provides management cluster CIDRs:

• Validate they don't overlap with our proposed defaults
• Adjust HostedCluster CIDRs if conflicts detected
• Document the conflict avoidance in the output

Step 3: Apply KubeVirt Provider Defaults

Required Parameters:

• --memory: Memory allocation for VMs (default: 8Gi)
• --cores: CPU cores for VMs (default: 2)
• --pull-secret: Path to pull secret file
• --release-image: OpenShift release image

IPv4 Non-Conflicting Defaults:

• --service-cidr: 172.30.0.0/16 (avoids common 10.x ranges)
• --cluster-cidr: 10.132.0.0/14 (avoids common 10.128.x range)
• --machine-cidr: 192.168.126.0/24 (avoids common 192.168.1.x range)

IPv6 Non-Conflicting Defaults:

• --service-cidr: fd02::/112
• --cluster-cidr: fd01::/48
• --machine-cidr: fd03::/64

Smart Defaults by Environment:

Development Environment:

--memory 8Gi
--cores 2
--control-plane-availability-policy SingleReplica
--node-pool-replicas 2

Production Environment:

--memory 16Gi
--cores 4
--control-plane-availability-policy HighlyAvailable
--node-pool-replicas 3
--auto-repair true

High-Performance Environment:

--memory 32Gi
--cores 8
--control-plane-availability-policy HighlyAvailable
--node-pool-replicas 5

Step 4: Interactive Parameter Collection

Required Information Collection:

1. Cluster Name

   🔹 **Cluster Name**: What would you like to name your cluster?
      - Must be DNS-compatible (lowercase, hyphens allowed)
      - Used for VM and resource naming
      - Example: dev-cluster, prod-app, test-env
   

2. Management Cluster Network Check (see Step 2)

3. VM Resource Configuration

   🔹 **VM Memory**: How much memory should each VM have?
      - Development: 8Gi (minimum recommended)
      - Production: 16Gi+ (better performance)
      - High-performance: 32Gi+ (intensive workloads)
      - [Press Enter for default based on environment]
   

   🔹 **VM CPU Cores**: How many CPU cores should each VM have?
      - Development: 2 cores (minimum recommended)
      - Production: 4+ cores (better performance)
      - High-performance: 8+ cores (intensive workloads)
      - [Press Enter for default based on environment]
   

4. Pull Secret

   🔹 **Pull Secret**: Path to your OpenShift pull secret file?
      - Required for accessing OpenShift container images
      - Download from: https://console.redhat.com/openshift/install/pull-secret
      - Example: /home/user/pull-secret.json
   

5. OpenShift Version

   🔹 **OpenShift Version**: Which OpenShift version do you want to use?
   
      📋 **Check supported versions**: https://amd64.ocp.releases.ci.openshift.org/
   
      - Enter release image URL: quay.io/openshift-release-dev/ocp-release:X.Y.Z-multi
      - [Press Enter for default: quay.io/openshift-release-dev/ocp-release:4.18.0-multi]
   

Optional Configuration:

6. IPv6 Support (if detected)

   🔹 **IPv6 Configuration**: Detected IPv6 requirement. Configure network stack:
      - ipv4: IPv4 only (default)
      - ipv6: IPv6 only
      - dual: Dual-stack (IPv4 + IPv6)
      - [Press Enter for default: ipv4]
   

7. Storage Class

   🔹 **Storage Class**: Which storage class should be used for VM disks?
      - List available storage classes on your cluster:
        kubectl get storageclass
      - [Press Enter to use cluster default]
   

8. Node Count

   🔹 **Node Pool Replicas**: How many worker nodes do you need?
      - Minimum: 2 (for basic redundancy)
      - Production recommended: 3+
      - [Press Enter for default based on environment type]
   

Step 5: Network CIDR Validation

If management cluster CIDRs provided, validate conflicts:

## Network Conflict Check

Management cluster networks:
- Service Network: 172.30.0.0/16
- Cluster Network: 10.128.0.0/14

HostedCluster networks (checking for conflicts):
✅ Service CIDR: 172.30.0.0/16 (safe - different range)
❌ Cluster CIDR: 10.132.0.0/14 (CONFLICT with 10.128.0.0/14)
✅ Machine CIDR: 192.168.126.0/24 (safe)

Adjusting Cluster CIDR to avoid conflict:
New Cluster CIDR: 10.140.0.0/14

If no management cluster info provided, use safe defaults:

## Network Configuration (Safe Defaults)

Using safe default CIDRs that avoid common management cluster ranges:
- Service CIDR: 172.30.0.0/16 (avoids 10.x ranges)
- Cluster CIDR: 10.132.0.0/14 (avoids common 10.128.x)
- Machine CIDR: 192.168.126.0/24 (avoids common 192.168.1.x)

Step 6: Generate Command

Basic KubeVirt Cluster Command:

hypershift create cluster kubevirt \
  --name <cluster-name> \
  --namespace <cluster-name>-ns \
  --memory <memory> \
  --cores <cores> \
  --pull-secret <pull-secret-path> \
  --release-image <release-image> \
  --service-cidr <service-cidr> \
  --cluster-cidr <cluster-cidr> \
  --machine-cidr <machine-cidr>

Development Configuration Example:

hypershift create cluster kubevirt \
  --name dev-cluster \
  --namespace dev-cluster-ns \
  --memory 8Gi \
  --cores 2 \
  --pull-secret /path/to/pull-secret.json \
  --release-image quay.io/openshift-release-dev/ocp-release:4.18.0-multi \
  --service-cidr 172.30.0.0/16 \
  --cluster-cidr 10.132.0.0/14 \
  --machine-cidr 192.168.126.0/24 \
  --control-plane-availability-policy SingleReplica \
  --node-pool-replicas 2

Production Configuration Example:

hypershift create cluster kubevirt \
  --name production-cluster \
  --namespace production-cluster-ns \
  --memory 16Gi \
  --cores 4 \
  --pull-secret /path/to/pull-secret.json \
  --release-image quay.io/openshift-release-dev/ocp-release:4.18.0-multi \
  --service-cidr 172.30.0.0/16 \
  --cluster-cidr 10.132.0.0/14 \
  --machine-cidr 192.168.126.0/24 \
  --control-plane-availability-policy HighlyAvailable \
  --node-pool-replicas 3 \
  --auto-repair

IPv6 Configuration Example:

hypershift create cluster kubevirt \
  --name ipv6-cluster \
  --namespace ipv6-cluster-ns \
  --memory 16Gi \
  --cores 4 \
  --pull-secret /path/to/pull-secret.json \
  --release-image quay.io/openshift-release-dev/ocp-release:4.18.0-multi \
  --service-cidr fd02::/112 \
  --cluster-cidr fd01::/48 \
  --machine-cidr fd03::/64

Disconnected Configuration Example:

hypershift create cluster kubevirt \
  --name airgapped-cluster \
  --namespace airgapped-cluster-ns \
  --memory 16Gi \
  --cores 4 \
  --pull-secret /path/to/pull-secret.json \
  --release-image quay.io/openshift-release-dev/ocp-release:4.18.0-multi \
  --service-cidr 172.30.0.0/16 \
  --cluster-cidr 10.132.0.0/14 \
  --machine-cidr 192.168.126.0/24 \
  --image-content-sources /path/to/image-content-sources.yaml \
  --additional-trust-bundle /path/to/ca-bundle.pem \
  --render

Step 7: Pre-Flight Validation

Provide validation commands:

## Pre-Flight Checks

Before creating the cluster, verify your KubeVirt setup:

1. **KubeVirt Status:**
   kubectl get kubevirt -A

2. **Available Storage Classes:**
   kubectl get storageclass

3. **Node Resources:**
   kubectl top nodes

4. **Available Memory/CPU:**
   kubectl describe nodes | grep -E "(Allocatable|Allocated)"

5. **Network Configuration:**
   oc get network cluster -o yaml

6. **Required Compute Resources:**
   - Control Plane VMs: 3 x (<cores> cores, <memory> RAM)
   - Worker VMs: <replica-count> x (<cores> cores, <memory> RAM)
   - Total Required: <total-cores> cores, <total-memory> RAM

Step 8: Post-Generation Instructions

For Disconnected Environments:

## Post-Creation Configuration (Disconnected)

After running the command above (with --render), you'll need to modify the generated manifests:

1. **Add ImageContentSources to HostedCluster:**
```yaml