# Linux Shell Script for VM Health Monitoring

### Linux Shell Script for VM Health Monitoring

I've created two shell scripts for you to monitor the VoIP service and automatically reboot your Proxmox VM when needed.

#### Simple Version.

Here's the basic script that does exactly what you asked for:

```bash
#!/bin/bash

# Simple VM Health Monitor
# Checks if http://www.your-domain.com responds, reboots VM 105 if not

URL="http://www.your-domain.com"
VM_ID="105"

# Check if URL responds (with 10 second timeout)
if ! curl -s --connect-timeout 10 --max-time 10 "$URL" > /dev/null 2>&1; then
    echo "$(date): Service not responding, rebooting VM $VM_ID"
    qm reboot "$VM_ID" && sleep 30 && qm start "$VM_ID"
    echo "$(date): VM reboot completed"
else
    echo "$(date): Service is responding normally"
fi
```

#### Enhanced Version (Production Ready)

```bash
#!/bin/bash

# VM Health Monitor Script
# This script checks if a web service is responding and reboots the VM if it's not

# Configuration
TARGET_URL="http://www.your-domain.com"
VM_ID="105"
TIMEOUT=10
MAX_RETRIES=3
LOG_FILE="/var/log/vm-health-monitor.log"

# Function to log messages with timestamp
log_message() {
    echo "$(date '+%Y-%m-%d %H:%M:%S') - $1" | tee -a "$LOG_FILE"
}

# Function to check if URL is responding
check_url() {
    local url="$1"
    local timeout="$2"
    
    # Use curl to check if the URL responds
    if curl -s --connect-timeout "$timeout" --max-time "$timeout" "$url" > /dev/null 2>&1; then
        return 0  # Success
    else
        return 1  # Failure
    fi
}

# Function to reboot VM
reboot_vm() {
    local vm_id="$1"
    
    log_message "Attempting to reboot VM $vm_id"
    
    # Stop the VM first
    if qm stop "$vm_id"; then
        log_message "VM $vm_id stopped successfully"
        sleep 30
        
        # Start the VM
        if qm start "$vm_id"; then
            log_message "VM $vm_id started successfully"
            return 0
        else
            log_message "ERROR: Failed to start VM $vm_id"
            return 1
        fi
    else
        log_message "ERROR: Failed to stop VM $vm_id"
        return 1
    fi
}

# Main monitoring function
main() {
    log_message "Starting health check for $TARGET_URL"
    
    local retry_count=0
    
    # Retry loop
    while [ $retry_count -lt $MAX_RETRIES ]; do
        if check_url "$TARGET_URL" "$TIMEOUT"; then
            log_message "Service is responding normally (attempt $((retry_count + 1))/$MAX_RETRIES)"
            exit 0
        else
            retry_count=$((retry_count + 1))
            log_message "Service not responding (attempt $retry_count/$MAX_RETRIES)"
            
            if [ $retry_count -lt $MAX_RETRIES ]; then
                sleep 5
            fi
        fi
    done
    
    # If we reach here, all retries failed
    log_message "Service failed to respond after $MAX_RETRIES attempts. Initiating VM reboot."
    
    if reboot_vm "$VM_ID"; then
        log_message "VM reboot completed successfully"
    else
        log_message "VM reboot failed - manual intervention required"
        exit 1
    fi
}

# Check if running as root (required for qm commands)
if [ "$EUID" -ne 0 ]; then
    echo "This script must be run as root (required for Proxmox qm commands)"
    exit 1
fi

# Create log directory if it doesn't exist
mkdir -p "$(dirname "$LOG_FILE")"

# Run main function
main

exit 0
```

#### Installation and Usage

##### 1. Save the Script

Save either script to a file (e.g., vm-health-monitor.sh) on your Proxmox host:

```shell
nano vm-health-monitor.sh
```

Paste the script content

##### 2. Make it Executable

```shell
chmod +x vm-health-monitor.sh
```

##### 3. Test the Script

```shell
sudo ./vm-health-monitor.sh
```

##### 4. Set up Automatic Monitoring (Cron Job)

To run the script automatically every 5 minutes:

```shell
sudo crontab -e
```

Add this line:

```shell
*/5 * * * * /path/to/vm-health-monitor.sh >> /var/log/vm-monitor.log 2>&1
```

#### Key Features

##### Simple Script:

- Direct implementation of your requirements
- Uses curl to check if the URL responds
- Executes qm reboot 105 && sleep 30 && qm start 105 if the service is down
- Minimal logging with timestamps

##### Enhanced Script:

- Retry Logic: Attempts 3 times before declaring service down
- Comprehensive Logging: Detailed logs with timestamps
- Error Handling: Proper error checking for VM operations
- Root Check: Ensures script runs with proper privileges
- Graceful Shutdown: Uses qm stop before qm start for cleaner reboot

##### Important Notes

- Root Privileges Required: The qm command requires root access, so run the script as root or with sudo
- Curl Dependency: Ensure curl is installed on your Proxmox host
- Network Timeout: Set to 10 seconds to avoid hanging on network issues
- VM ID: Currently set to 105 as specified - modify if needed
- Logging: Enhanced version logs to /var/log/vm-health-monitor.log

Both scripts will effectively monitor your VoIP service and automatically reboot VM 105 when the service becomes unresponsive, ensuring minimal downtime for your infrastructure.

#### Download the scripts.

##### Simple version

Attachment link : [vm\_health\_monitoring\_simple.sh](https://docs.greenhome.stream/attachments/24)

##### Enhanced version

Attachment link : [vm\_health\_monitoring\_enhanced.sh](https://docs.greenhome.stream/attachments/25)

<span style="color: rgb(224, 62, 45);">**Ins0mniA**</span>