When deploying VMware ESXi servers in remote offices with APC UPS backup, we need a reliable way to trigger graceful shutdowns during power outages. The standard APC PowerChute Network Shutdown solution requires additional infrastructure (network cards and management servers), which isn't always practical for smaller deployments with Back-UPS Pro models that only have USB connectivity.

ESXi has limited built-in UPS support compared to full Linux distributions. The hypervisor doesn't natively recognize USB-connected UPS devices or provide power management daemons like Network UPS Tools (NUT). This leaves us needing a custom solution.

Here are two approaches that have worked for ESXi 5.1 and later versions:

Option 1: ESXi Custom Script with USB Passthrough

This method requires passing the USB controller to a Linux VM that can monitor the UPS:

# Add to VMX configuration:
usb.present = "TRUE"
usb.generic.allowHID = "TRUE"
usb.quirks.device0 = "0xabcd:0x1234 allow"  # Replace with UPS vendor/product IDs

Then install NUT in the Linux VM with configuration:

# /etc/nut/ups.conf
[apcups]
    driver = usbhid-ups
    port = auto
    vendorid = 051D

Option 2: ESXi SSH Script with USB Monitoring

For a more lightweight approach using just ESXi:

#!/bin/sh
# /vmfs/volumes/datastore1/scripts/ups-monitor.sh

while true; do
    if ! lsusb | grep -q "APC"; then
        /sbin/shutdown.sh && exit
    fi
    sleep 30
done

Add to crontab with:

* * * * * /vmfs/volumes/datastore1/scripts/ups-monitor.sh >/dev/null 2>&1

1. Test shutdown procedures thoroughly before deployment
2. Consider battery runtime when setting monitoring intervals
3. For ESXi 6.7+, check if native PowerCLI cmdlets can help
4. Always document the solution for local IT staff

If you're using vCenter, you can create a VM alarm that triggers on UPS events:

$alarmMgr = Get-View AlarmManager
$alarm = New-Object VMware.Vim.AlarmSpec
$alarm.Name = "UPS Power Failure"
$alarm.Description = "Triggers when UPS battery is low"
$alarm.Enabled = $TRUE
# Add trigger conditions and actions here
$alarmMgr.CreateAlarm("Folder-group-d1", $alarm)

When deploying ESXi 5.1 servers in remote offices with APC Back-UPS Pro units, the standard network-based shutdown solutions (like PowerChute Network Shutdown) become impractical. The USB connection presents both an opportunity and a technical hurdle since ESXi doesn't natively support USB UPS monitoring.

The solution involves a two-layer approach:

1. USB-to-NUT (Network UPS Tools) translation layer
2. ESXi-side monitoring script

Prerequisites:

- APC UPS with USB (e.g., Back-UPS Pro 1500)
- ESXi 5.1 host with SSH access
- Temporary Linux machine (can be live CD)

Even without a dedicated server, you can use a minimal Linux setup:

# On Ubuntu/Debian:
sudo apt-get install nut nut-client nut-server
sudo usermod -a -G nut $USER

# Configure /etc/nut/ups.conf:
[apcups]
driver = usbhid-ups
port = auto

Save this as /usr/bin/ups-monitor.sh on ESXi:

#!/bin/sh

NUT_SERVER="linux-gateway-ip"
UPS_NAME="apcups"
POLL_INTERVAL=60

while true; do
    STATUS=$(nc $NUT_SERVER 3493 <<< "LIST STATUS $UPS_NAME" | grep -q "OB" && echo "OnBattery")
    
    if [ "$STATUS" = "OnBattery" ]; then
        BATTERY_LEVEL=$(nc $NUT_SERVER 3493 <<< "LIST VAR $UPS_NAME" | grep battery.charge | awk -F'"' '{print $2}')
        
        if [ "$BATTERY_LEVEL" -lt 20 ]; then
            # Initiate shutdown sequence
            localcli system shutdown poweroff -d 60 -r "UPS triggered shutdown"
            exit 0
        fi
    fi
    
    sleep $POLL_INTERVAL
done

Add this to /etc/rc.local before 'exit 0':

/usr/bin/ups-monitor.sh &

For environments where a Linux gateway isn't feasible:

# Identify USB device:
lsusb | grep "American Power Conversion"

# Add to /etc/vmware/esx.conf:
/usb/0/device = "0000:00:1a.0"
/usb/0/vendor = "0x051d"
/usb/0/product = "0x0002"

• Verify USB visibility with: lsusb -v | grep -i apc
• Check NUT server connectivity: nc -zv gateway-ip 3493
• Monitor script execution: ps | grep ups-monitor

Adjust the shutdown thresholds based on your: