openshift-metal3 · MahnoorAsghar · Nov 7, 2025
diff --git a/.add_worker_implementation_summary.md b/.add_worker_implementation_summary.md
@@ -0,0 +1,234 @@
+# Implementation Summary: Post-Installation Worker Node Addition
+
+## What Was Created
+
+### Core Scripts
+
+1. **`add_worker_node.sh`** - Main script to add worker nodes
+   - Creates libvirt VM with customizable resources
+   - Configures virtual BMC (vbmc or sushy-tools)
+   - Generates BareMetalHost and Secret manifests
+   - Provides step-by-step instructions for completion
+   - Automatically finds available BMC ports and generates unique MAC addresses
+
+2. **`remove_worker_node.sh`** - Cleanup script to remove worker nodes
+   - Drains and deletes node from cluster
+   - Removes BareMetalHost and Machine resources
+   - Destroys VM and cleans up disk/NVRAM
+   - Removes BMC configuration
+
+3. **`auto_approve_csrs.sh`** - Helper script for CSR approval
+   - Auto-approves pending CSRs for specified duration
+   - Useful for development/testing scenarios
+   - Default 30-minute duration
+
+### Documentation
+
+1. **`docs/add-worker-post-install.md`** - Complete documentation
+   - Detailed usage instructions
+   - Configuration options
+   - Complete workflow examples
+   - Troubleshooting guide
+   - Architecture notes
+
+2. **`WORKER_QUICK_START.md`** - Quick reference guide
+   - TL;DR commands
+   - Common use cases
+   - Quick examples
+
+3. **`README.md`** - Updated main README
+   - Added new "Option 1: Add Workers Post-Installation"
+   - Kept existing pre-configuration method as "Option 2"
+   - Links to new documentation
+
+### Makefile Integration
+
+Added two new targets to `Makefile`:
+- `make add_worker WORKER_NAME=<name>` - Add a worker
+- `make remove_worker WORKER_NAME=<name>` - Remove a worker
+
+## Key Features
+
+### 1. No Pre-Planning Required
+Unlike the existing methods, this solution allows adding workers **after** deployment without requiring `NUM_EXTRA_WORKERS` to be set beforehand.
+
+### 2. Flexible Configuration
+Users can customize worker resources via environment variables:
+```bash
+export EXTRA_WORKER_MEMORY=32768  # 32GB
+export EXTRA_WORKER_DISK=100      # 100GB
+export EXTRA_WORKER_VCPU=16       # 16 cores
+```
+
+### 3. Smart Automation
+- Automatically finds available BMC ports
+- Generates unique MAC addresses
+- Detects and starts BMC containers if needed
+- Supports both IPMI and Redfish BMC protocols
+- Handles UEFI/BIOS firmware automatically
+
+### 4. Complete Lifecycle Management
+- Add workers: `add_worker_node.sh`
+- Remove workers: `remove_worker_node.sh`
+- Auto-approve CSRs: `auto_approve_csrs.sh`
+
+### 5. Safety Checks
+- Validates cluster connectivity
+- Checks for VM name conflicts
+- Checks for BareMetalHost conflicts
+- Validates worker name format
+
+## Usage Comparison
+
+### Old Method (Pre-Configuration Required)
+```bash
+# BEFORE initial deployment
+export NUM_EXTRA_WORKERS=2
+export EXTRA_WORKERS_ONLINE_STATUS=false
+make
+
+# AFTER deployment
+oc apply -f ocp/ostest/extra_host_manifests.yaml
+oc scale machineset ostest-worker-0 --replicas=3 -n openshift-machine-api
+```
+
+### New Method (Post-Installation)
+```bash
+# Deploy cluster normally
+make
+
+# LATER: Add worker on demand
+./add_worker_node.sh my-worker-1
+oc apply -f ocp/ostest/my-worker-1_bmh.yaml
+./auto_approve_csrs.sh 30 &
+oc scale machineset ostest-worker-0 --replicas=3 -n openshift-machine-api
+```
+
+## Architecture
+
+### VM Creation
+- Uses libvirt XML to define VM
+- Supports x86_64 and aarch64 architectures
+- Configures UEFI or BIOS boot
+- Connects to baremetal network
+- Allocates disk storage in `/var/lib/libvirt/images/`
+
+### BMC Configuration
+Two protocols supported:
+
+1. **IPMI** (via vbmc)
+   - Port range: 6230-6250
+   - Protocol: `ipmi://<host>:<port>`
+   - Container: vbmc
+
+2. **Redfish** (via sushy-tools)
+   - Port: 8000 (HTTP)
+   - Protocol: `redfish-virtualmedia+http://<host>:8000/<vm-name>`
+   - Container: sushy-tools
+   - Default choice
+
+### BareMetalHost Integration
+Generated manifest includes:
+- Secret with BMC credentials (admin/password)
+- BareMetalHost spec with:
+  - BMC address and credentials
+  - Boot MAC address
+  - Online status (true)
+  - Automated cleaning mode (disabled)
+
+## Testing
+
+All scripts pass bash syntax validation:
+```bash
+bash -n add_worker_node.sh       # ✓ PASS
+bash -n remove_worker_node.sh    # ✓ PASS
+bash -n auto_approve_csrs.sh     # ✓ PASS
+```
+
+## Files Modified/Created
+
+### New Files
+- `add_worker_node.sh` (executable)
+- `remove_worker_node.sh` (executable)
+- `auto_approve_csrs.sh` (executable)
+- `docs/add-worker-post-install.md`
+- `WORKER_QUICK_START.md`
+- `.add_worker_implementation_summary.md` (this file)
+
+### Modified Files
+- `Makefile` - Added `add_worker` and `remove_worker` targets
+- `README.md` - Updated "Testing with extra workers" section
+
+## Dependencies
+
+The scripts leverage existing dev-scripts infrastructure:
+- `common.sh` - Environment variables and common functions
+- `network.sh` - Network configuration
+- `utils.sh` - Utility functions
+- `ocp_install_env.sh` - OCP environment setup
+- `logging.sh` - Logging functions
+
+## Compatibility
+
+- Works with standard installer flow (`make` or `make all`)
+- Compatible with existing `NUM_EXTRA_WORKERS` workflow
+- Supports both IPMI and Redfish BMC protocols
+- Works with UEFI and BIOS boot modes
+- Supports x86_64 and aarch64 architectures
+
+## Next Steps for Users
+
+1. **Basic Usage**
+   ```bash
+   ./add_worker_node.sh worker-1
+   oc apply -f ocp/ostest/worker-1_bmh.yaml
+   oc scale machineset <name> --replicas=<N+1> -n openshift-machine-api
+   ```
+
+2. **With Custom Resources**
+   ```bash
+   export EXTRA_WORKER_MEMORY=32768 EXTRA_WORKER_DISK=100 EXTRA_WORKER_VCPU=16
+   ./add_worker_node.sh large-worker
+   ```
+
+3. **Quick Start with Make**
+   ```bash
+   make add_worker WORKER_NAME=worker-1
+   ```
+
+4. **Auto-approve CSRs**
+   ```bash
+   ./auto_approve_csrs.sh 30 &
+   ```
+
+## Limitations
+
+1. Only works with libvirt-based deployments
+2. Requires BMC containers (vbmc/sushy-tools) to be available
+3. BMC port range limited to available ports in 6230-6250
+4. Worker must be on same network as other cluster nodes
+5. Resources (memory, disk, CPU) are set at VM creation time
+
+## Future Enhancements
+
+Possible improvements for future versions:
+- Support for multiple workers in one command
+- Interactive mode with prompts
+- Integration with Ansible playbooks
+- Support for additional disk attachment
+- Network configuration customization
+- BMC port range expansion
+- Support for non-libvirt platforms
+
+## Support
+
+For issues or questions:
+1. Check the documentation: `docs/add-worker-post-install.md`
+2. Review quick start: `WORKER_QUICK_START.md`
+3. Check script output for detailed instructions
+4. Verify cluster connectivity and resources
+
+## Conclusion
+
+This implementation provides a complete, flexible solution for adding worker nodes to dev-scripts clusters post-installation, eliminating the need for pre-planning and making it easier to scale clusters on demand for testing and development purposes.
+
diff --git a/Makefile b/Makefile
@@ -66,6 +66,12 @@ install_config:
 ocp_run:
 	./06_create_cluster.sh
 
+add_worker:
+	./add_worker_node.sh $(WORKER_NAME)
+
+remove_worker:
+	./remove_worker_node.sh $(WORKER_NAME)
+
 gather:
 	./must_gather.sh
 

diff --git a/README.md b/README.md
@@ -495,7 +495,31 @@ export IGNITION_EXTRA="ignition/file_example.ign"
 
 ### Testing with extra workers
 
-It is possible to specify additional workers, which are not used in the initial
+#### Option 1: Add Workers Post-Installation (No Pre-Planning Required)
+
+You can add worker nodes **after** your cluster is deployed without requiring pre-configuration:
+
+```bash
+# Add a worker node
+./add_worker_node.sh my-worker-1
+
+# Apply the generated manifest
+oc apply -f ocp/ostest/my-worker-1_bmh.yaml
+
+# Scale the machineset to provision it
+oc scale machineset <cluster-name>-worker-0 --replicas=<N+1> -n openshift-machine-api
+```
+
+Or using Make:
+```bash
+make add_worker WORKER_NAME=my-worker-1
+```
+
+See [WORKER_QUICK_START.md](WORKER_QUICK_START.md) for a quick guide or [docs/add-worker-post-install.md](docs/add-worker-post-install.md) for complete documentation.
+
+#### Option 2: Pre-Configure Extra Workers (Traditional Method)
+
+You can specify additional workers during initial deployment, which are not used in the initial
 deployment, and can then later be used e.g to test scale-out. The default online
 status of the extra workers is true, but can be changed to false using
 EXTRA_WORKERS_ONLINE_STATUS.

diff --git a/WORKER_QUICK_START.md b/WORKER_QUICK_START.md
@@ -0,0 +1,66 @@
+# Quick Start: Adding Workers Post-Installation
+
+## TL;DR
+
+Add a worker node after your cluster is already deployed:
+
+```bash
+# Add a worker
+./add_worker_node.sh my-worker-1
+
+# Apply the generated manifest
+oc apply -f ocp/ostest/my-worker-1_bmh.yaml
+
+# Auto-approve CSRs in background
+./auto_approve_csrs.sh 30 &
+
+# Scale up your machineset
+oc get machineset -n openshift-machine-api
+oc scale machineset <your-cluster>-worker-0 --replicas=<N+1> -n openshift-machine-api
+
+# Watch it join
+oc get nodes -w
+```
+
+## Customizing Resources
+
+```bash
+export EXTRA_WORKER_MEMORY=32768  # 32GB RAM
+export EXTRA_WORKER_DISK=100      # 100GB disk
+export EXTRA_WORKER_VCPU=16       # 16 vCPUs
+
+./add_worker_node.sh my-large-worker
+```
+
+## Using Make
+
+```bash
+# Add worker
+make add_worker WORKER_NAME=worker-1
+
+# Remove worker
+make remove_worker WORKER_NAME=worker-1
+```
+
+## What Gets Created
+
+- ✅ Libvirt VM with specified resources
+- ✅ Virtual BMC (IPMI or Redfish)
+- ✅ BareMetalHost manifest
+- ✅ Secret for BMC credentials
+- ✅ Complete setup instructions
+
+## Removing a Worker
+
+```bash
+# Remove from cluster and delete VM
+./remove_worker_node.sh my-worker-1
+
+# Don't forget to scale down the machineset
+oc scale machineset <your-cluster>-worker-0 --replicas=<N-1> -n openshift-machine-api
+```
+
+## Full Documentation
+
+See [docs/add-worker-post-install.md](docs/add-worker-post-install.md) for detailed documentation.
+