ESXi 8.0U3 Upgrade Guide

Overview

This guide documents the successful automated upgrade of Intel NUC6i7KYK homelab infrastructure from ESXi 7.0.3 to ESXi 8.0U3 using offline bundles and remote automation.

Infrastructure Upgraded

Hardware Platform

  • Model: Intel NUC6i7KYK (Skull Canyon)
  • CPU: Intel Core i7-6770HQ (Skylake generation)
  • Memory: 64GB DDR4 per host
  • Storage: 250GB NVMe SSD per host
  • Network: Dual NIC (built-in + USB adapter)

Host Details

| Host | IP Address | Before | After | Status | |——|————|———|——-|———| | esxi-nuc-01 | 192.168.10.8 | ESXi 7.0.3 build-21424296 | ESXi 8.0.3 build-24022510 | ✅ Success | | esxi-nuc-02 | 192.168.10.9 | ESXi 7.0.3 build-21424296 | ESXi 8.0.3 build-24022510 | ✅ Success | | esxi-nuc-03 | 192.168.10.10 | ESXi 7.0.3 build-21424296 | ESXi 8.0.3 build-24022510 | ✅ Success |

Hardware Compatibility

Mixed Environment Overview

The homelab runs a mixed ESXi environment due to hardware compatibility requirements:

Hardware CPU Architecture ESXi 7.0.x ESXi 8.0.x Current Version
Intel NUC6i7KYK (x3) Skylake (2016) ✅ Supported ⚠️ Works with warnings 8.0.3 ✅
Mac Pro Late 2013 Ivy Bridge (2013) ✅ Supported ❌ Not supported 7.0.3 ✅

Intel NUC6i7KYK Support Status

✅ ESXi 8.0 Compatible with important notes:

  1. Skylake CPU Deprecation Warning: The Intel Core i7-6770HQ (Skylake) processor shows deprecation warnings during ESXi 8.0 installation/upgrade
  2. Current Support: Fully functional with ESXi 8.0.x releases
  3. Future Support: Will NOT be supported in vSphere releases after 8.0.x
  4. Required Flag: --no-hardware-warning must be used to bypass warnings

Warning Message 

CPU_SUPPORT WARNING: The CPU on this host may not be supported in future ESXi releases. 
Please plan accordingly. Please refer to KB 82794 for more details.

Upgrade Method: Offline Bundle Approach

Why Offline Bundle vs ISO

  1. Direct Integration: Works natively with esxcli commands
  2. Remote Execution: No physical USB drive required
  3. Automation Friendly: Can be scripted and executed remotely
  4. Reliable Validation: Bundle validation works correctly with ESXi

Source Files

  • Bundle: VMware-ESXi-8.0U3-24022510-depot.zip (599MB)
  • Location: /Users/markalston/backup/homelab/artifacts/VMware vSphere - Enterprise Plus 8.0/VMware vSphere Hypervisor (ESXi)/VMware vSphere Hypervisor (ESXi) Offline Bundle/

Automated Upgrade Script

Script: upgrade-esxi-remote.sh

Location: /scripts/upgrade-esxi-remote.sh

Key Features:

  • Automated host discovery from SSH config
  • Pre-upgrade configuration backup
  • Free space verification
  • Bundle upload and validation
  • Hardware warning bypass for Intel NUCs
  • Maintenance mode management
  • Automatic reboot and verification
  • Post-upgrade cleanup

Usage Examples 

# Upgrade all ESXi hosts automatically
./scripts/upgrade-esxi-remote.sh

# Upgrade specific host
./scripts/upgrade-esxi-remote.sh esxi-nuc-01

# Use custom bundle path
./scripts/upgrade-esxi-remote.sh esxi-nuc-01 /path/to/depot.zip

Script Configuration 

# Key configuration variables
SSH_KEY_PATH="${HOME}/.ssh/esxi_homelab"
ESXI_USER="root"
BUNDLE_LOCAL_PATH="/Users/markalston/backup/homelab/artifacts/..."
BACKUP_DIR="/Users/markalston/backup/homelab/esxi-config-backups"

Manual Upgrade Process

Prerequisites

  1. SSH key authentication configured (deploy-esxi-ssh-keys.sh)
  2. Sufficient datastore space (2GB+ free)
  3. Offline bundle downloaded locally
  4. Network connectivity to all hosts

Step-by-Step Manual Process

1. Upload Offline Bundle 

scp -i ~/.ssh/esxi_homelab "VMware-ESXi-8.0U3-24022510-depot.zip" \
    root@esxi-nuc-01:/vmfs/volumes/esxi-nuc-01-ssd-local/

2. Validate Bundle 

ssh esxi-nuc-01 "esxcli software sources profile list \
    -d /vmfs/volumes/esxi-nuc-01-ssd-local/VMware-ESXi-8.0U3-24022510-depot.zip"

Expected output:

Name                          Vendor        Acceptance Level
ESXi-8.0U3-24022510-standard  VMware, Inc.  PartnerSupported
ESXi-8.0U3-24022510-no-tools  VMware, Inc.  PartnerSupported

3. Enter Maintenance Mode 

ssh esxi-nuc-01 "esxcli system maintenanceMode set -e true"

4. Perform Upgrade 

ssh esxi-nuc-01 "esxcli software profile update \
    -d /vmfs/volumes/esxi-nuc-01-ssd-local/VMware-ESXi-8.0U3-24022510-depot.zip \
    -p ESXi-8.0U3-24022510-standard \
    --force \
    --no-hardware-warning"

5. Reboot Host 

ssh esxi-nuc-01 "reboot"

6. Verify Upgrade 

# Wait for reboot, then verify
ssh esxi-nuc-01 "vmware -v"
# Expected: VMware ESXi 8.0.3 build-24022510

7. Exit Maintenance Mode 

ssh esxi-nuc-01 "esxcli system maintenanceMode set -e false"

8. Cleanup 

ssh esxi-nuc-01 "rm -f /vmfs/volumes/esxi-nuc-01-ssd-local/VMware-ESXi-8.0U3-24022510-depot.zip"

Critical Flags and Parameters

Required esxcli Flags

  1. --force: Bypasses dependency and acceptance level checks
  2. --no-hardware-warning: Essential for Intel NUC6i7KYK Skylake CPUs
  3. -p ESXi-8.0U3-24022510-standard: Use standard profile (not no-tools)

Command Template 

esxcli software profile update \
    -d /path/to/depot.zip \
    -p ESXi-8.0U3-24022510-standard \
    --force \
    --no-hardware-warning

Pre-Upgrade Backup Strategy

Automatic Backups Created

  1. ESXi Configuration Bundle
    • Created via: vim-cmd hostsvc/firmware/backup_config
    • Location: http://*/downloads/{uuid}/configBundle-{hostname}.tgz
    • Local backup: /Users/markalston/backup/homelab/esxi-config-backups/{host}/{timestamp}/
  2. VIB Inventory
    • Command: esxcli software vib list
    • File: vibs-before-upgrade.txt
  3. Version Information
    • Command: vmware -v
    • File: version-before-upgrade.txt

Backup Verification 

# Verify backups exist
ls -la /Users/markalston/backup/homelab/esxi-config-backups/*/

Network and DNS Configuration

Domain Setup

All hosts configured with professional domain:

  • Domain: markalston.net
  • FQDNs:
    • esxi-nuc-01.markalston.net
    • esxi-nuc-02.markalston.net
    • esxi-nuc-03.markalston.net

Route 53 DNS Records

Direct A records configured (no CNAME chains):

esxi-nuc-01.markalston.net → 192.168.10.8
esxi-nuc-02.markalston.net → 192.168.10.9
esxi-nuc-03.markalston.net → 192.168.10.10

Troubleshooting

Common Issues and Solutions

1. Bundle Validation Failed

Problem: esxcli software sources profile list fails

Solutions:

  • Verify bundle was uploaded completely
  • Check file permissions: chmod 644 depot.zip
  • Ensure sufficient datastore space
  • Try re-uploading the bundle

2. Hardware Warning Blocks Upgrade

Problem: Upgrade fails with CPU support warning

Solution: Add --no-hardware-warning flag to upgrade command

3. Maintenance Mode Issues

Problem: Host won’t enter maintenance mode

Solutions:

  • Ensure no running VMs (migrate or shut down)
  • Check for vCenter connection issues
  • Force maintenance mode if necessary

4. SSH Connection Refused After Reboot

Problem: Cannot SSH to host after upgrade

Solutions:

  • Wait longer (ESXi 8.0 takes more time to boot)
  • Check if host is still rebooting via ping
  • Try connecting via IP address instead of hostname
  • Verify SSH service started: services.sh status

5. Upgrade Rollback

Problem: Need to revert to ESXi 7.0.3

Process:

  1. Boot from ESXi 7.0.3 installation media
  2. Choose “Upgrade” option
  3. Select previous installation
  4. Restore from configuration backup

Verification Procedures

Post-Upgrade Checklist

  1. Version Verification 
    ssh esxi-host "vmware -v"
# Expected: VMware ESXi 8.0.3 build-24022510
  2. Hostname/Domain Check 
    ssh esxi-host "esxcli system hostname get"
  3. Network Connectivity 
    ping esxi-nuc-01.markalston.net
ping esxi-nuc-02.markalston.net
ping esxi-nuc-03.markalston.net
  4. Web Interface Access 
    curl -k -I https://esxi-nuc-01.markalston.net
  5. Datastore Health 
    ssh esxi-host "esxcli storage filesystem list"
  6. VIB Status 
    ssh esxi-host "esxcli software vib list | head -10"

Performance and Security Improvements

ESXi 8.0.3 New Features

  • Enhanced security with TPM 2.0 support
  • Improved container support
  • Better GPU passthrough capabilities
  • Enhanced vSAN features
  • Improved DRS and vMotion performance

Homelab Benefits

  • Real SSL Certificates: Can now use Let’s Encrypt with markalston.net
  • Better Automation: Enhanced API capabilities
  • Improved Monitoring: Better integration with modern tools
  • Enhanced Security: Latest security patches and features

Future Considerations

Hardware Refresh Planning

  • Intel NUC6i7KYK will NOT be supported beyond vSphere 8.0.x
  • Consider upgrading to newer hardware for future vSphere releases
  • Target: 7th generation Intel or newer for long-term support
  1. Current: Intel NUC6i7KYK with ESXi 8.0.3 ✅
  2. Next: Migrate to supported hardware before vSphere 9.0
  3. Options: Intel NUC12/13 Pro or MINISFORUM MS-A2

Monitoring

  • Set up alerts for CPU deprecation warnings
  • Monitor VMware HCL updates
  • Plan hardware refresh timeline

Scripts and Automation

Created Scripts

  • upgrade-esxi-remote.sh - Automated upgrade script
  • update-route53-records.sh - DNS management
  • update-esxi-domains.sh - Domain configuration
  • backup-esxi-config.sh - Configuration backup

Script Locations

All scripts located in /scripts/ directory with proper permissions and documentation.

Summary

The ESXi 8.0U3 upgrade was successfully completed using automated offline bundle deployment across all three Intel NUC6i7KYK hosts. Despite Skylake CPU deprecation warnings, the hardware remains fully functional with ESXi 8.0.x releases. The infrastructure now features:

  • ✅ Latest ESXi 8.0.3 with enhanced security and performance
  • ✅ Professional DNS setup using markalston.net domain
  • ✅ Automated upgrade and management capabilities
  • ✅ Comprehensive backup and recovery procedures
  • ✅ Future-ready platform for advanced vSphere features

Upgrade Date: July 20, 2025 Success Rate: 100% (3/3 hosts) Downtime per Host: ~5-10 minutes (reboot time only)

This project is for educational and home lab purposes.