# 🧩 Zerto WSFC VPG Ownership Automation

## Overview
This PowerShell script automates synchronization between **Windows Server Failover Cluster (WSFC)** node ownership and **Zerto Virtual Protection Groups (VPGs)**.

When WSFC ownership changes, the script automatically:
- **Resumes** replication for the active node’s VPG
- **Pauses** replication for the standby node’s VPG
- Ensures only the current WSFC owner continues replication to maintain CBT consistency

It supports two detection modes: **Disk-based** and **Group-based** ownership detection.

---

## 🖼️ Architecture Overview

### Owner: Node 1
![WSFC Node1 Ownership](./Zerto%20Cluster%20Monitor-Node%201%20-%20Owner.drawio.png)

- **WSFC Node1** owns the shared disk or owns the cluster group.
- **VPG Node1** is **Active** (replicating).
- **VPG Node2** is **Paused**.
- ZVM Prod and ZVM DR maintain CBT replication across sites.

### Owner: Node 2
![WSFC Node2 Ownership](./Zerto%20Cluster%20Monitor-Node%202%20-%20Owner.drawio.png)

- Ownership of the **WSFC shared disk** transfers to **Node2**.
- The script detects the ownership change.
- **VPG Node2** is resumed; **VPG Node1** is paused.
- Zerto continues replication with no data collision.

---

## ⚙️ Features
- ✅ Disk-based and Group-based WSFC ownership detection
- ✅ Automatic VPG resume/pause alignment
- ✅ Detailed timestamped logging (`C:\Temp\PwshCompat`)
- ✅ Compatible with PowerShell 5.1+ and PowerShell 7
- ✅ Safe retry and graceful error handling

---

## 🔧 Configuration

All configuration is centralized at the top of the script:

```powershell
# --- HARD-CODED CONFIG ---
$ZvmHost        = '192.168.222.20'
$ZvmUser        = 'admin'
$ZvmPassPlain   = 'password'

$NodeUser       = '.\wsfcadm'
$NodePassPlain  = 'password'

$ClusterFqdn    = 'TOR-HV01.lab.local'
$WSFCGroupName  = 'Cluster Group'
$Node1          = 'TOR-HV01-N1'
$Node2          = 'TOR-HV01-N2'

# OWNERSHIP DETECTION MODE
# 'Disk'  => determine active owner by shared disk ownership (preferred)
# 'Group' => determine active owner by Cluster Group ownership (legacy behavior)
$OwnershipSource = 'Disk'

# DISK MONITORING CONFIGURATION (used when OwnershipSource = 'Disk')
$SharedDiskUniqueId = '6589CFC000000307DC30980C15CE8818'
$SharedDiskLabel    = 'WSFCData1'
$DiskResourceName   = 'Cluster Disk 1'

# Zerto VPG names
$VpgName1 = 'Node1'
$VpgName2 = 'node2'
```

---

## 🧠 Detection Modes

### Disk Mode (Preferred)
In this mode, the script determines the active WSFC node by checking:
1. The **Physical Disk Resource Owner** in the cluster (`Get-CimInstance root\MSCluster`).
2. If unavailable, it checks which node has the disk **Online and Read/Write**.

This is the most reliable method for shared-disk clusters.

### Group Mode (Legacy)
In this mode, the script determines ownership by checking the **Cluster Group owner** instead of a shared disk.  
Useful when the cluster has no shared disks (e.g., cluster-only workloads).

```powershell
$OwnershipSource = 'Group'
```

---

## 🪵 Logging

Logs are created under:
```
C:\Temp\PwshCompat\cluster-monitor-YYYYMMDD-HHMMSS.log
```

Each log line includes timestamp, component, and log level (`DEBUG`, `INFO`, `WARN`, `ERROR`).

---

## 🧠 How It Works
1. Loads **FailoverClusters** and **Zerto.ZvmLinux.Commandlets** modules.
2. Connects to the ZVM using the provided credentials.
3. Retrieves both VPGs and their current states.
4. Determines the active WSFC owner (via disk or group).
5. Resumes or pauses VPGs to match ownership.
6. Logs all actions with timestamps.

---

## 🚀 Execution

Run from a system with network access to both WSFC nodes and ZVM:

```powershell
.\WSFC-Zerto-Monitor.ps1
```

Administrator privileges are recommended.

The script should run on a scheduled basis (i.e. every minute)

---

## 🧾 Legal Disclaimer

This script is provided as an **example only** and is **not supported** under any Zerto support program or service.

> The author and Zerto disclaim all implied warranties, including merchantability and fitness for a particular purpose.  
> In no event shall Zerto or the author be liable for damages arising from the use or inability to use this script.  
> Use at your own risk.

---

**Author:** Kosta Mushkin  
**Company:** Zerto (HPE)  
**Version:** 1.0  
**Date:** October 2025