Upgrading VMware Tools on critical VMs is a sensitive operation that demands meticulous planning and execution to mitigate risks of downtime or other complications. Here’s a structured approach to help you plan and execute the upgrade using vSphere Lifecycle Manager (vLCM) or Update Manager in ESXi 8.

1. Preparation & Planning

• Identify VMs: List all critical VMs that require VMware Tools upgrades.
• Communicate: Notify all relevant stakeholders and users about the planned upgrade and expected downtime, if any.
• Schedule: Allocate a suitable time frame preferably during off-peak hours or a maintenance window.
• Backup & Snapshot: Backup critical VMs and take snapshots to allow rollback in case of any issues.
• Review Dependencies: Assess dependencies between services running on the VMs and plan the sequence of upgrades accordingly.
• Test: If possible, test the upgrade process on non-critical or duplicate VMs to ensure there are no unexpected problems.

2. Setup Baselines in Update Manager

• Create Baseline: In the Update Manager, create a new baseline for VMware Tools upgrade.
• Attach Baseline: Attach the created baseline to the critical VMs or to the cluster/hosts where the VMs reside.

3. Implementation & Monitoring

• Monitor VM Health: Prior to initiating the upgrade, ensure that the VMs are in a healthy state and that there are no underlying issues.
• Initiate Upgrade: Start the upgrade process for one VM or a small group of VMs and closely monitor the progress.
• Verify Functionality: After the upgrade, confirm that all services and applications on the upgraded VMs are running as expected.
• Rollback if Necessary: If any issues are detected, use the snapshots taken earlier to roll back the VMs to their previous state.

4. Documentation & Communication

• Document: Log the details of the upgrade, including the date, time, affected VMs, and any issues encountered and resolved during the upgrade.
• Communicate: Once the upgrade is successful and you have verified the functionality of the critical VMs, inform all stakeholders and users about the completion of the upgrade and any subsequent steps they may need to take.

5. Cleanup & Review

• Remove Snapshots: Once you have confirmed that the VMs are stable, remove the snapshots to free up storage space.
• Review: Hold a review meeting to discuss any issues encountered during the upgrade process and how they were resolved, and identify any areas for improvement in the upgrade process.
• Update Documentation: Update any documentation or configuration management databases with the new VMware Tools versions.

Example of Initiating Upgrade in Update Manager

• Go to the “Updates” tab of the respective VMs or hosts in the vSphere Client.
• Select the attached baseline and click “Remediate”.
• Follow the wizard to start the upgrade process.

Conclusion:

Performing VMware Tools upgrades for critical VMs in a structured, cautious manner is crucial. Ensuring meticulous planning, regular communication, and thorough testing can help in minimizing the impact and ensuring a smooth upgrade process.

# Connect to the vCenter Server
$server = "your_vcenter_server"
$user = "your_username"
$pass = "your_password"
Connect-VIServer -Server $server -User $user -Password $pass

# Get all the VMs
$vms = Get-VM

foreach ($vm in $vms) {
    try {
        Write-Output "Processing VM: $($vm.Name)"
        
        # Check if the VM is powered on
        if ($vm.PowerState -eq "PoweredOn") {
            
            # Check if VMware Tools are out-of-date
            if ((Get-VMGuest -VM $vm).ToolsVersionStatus -eq 'GuestToolsNeedUpgrade') {
                
                Write-Output "Upgrading VMware Tools on $($vm.Name) ..."
                
                # Upgrade VMware Tools to the latest version
                Update-Tools -VM $vm -NoReboot -Confirm:$false
                
                Write-Output "Successfully initiated upgrade of VMware Tools on $($vm.Name)."
            } else {
                Write-Output "VMware Tools on $($vm.Name) are already up-to-date."
            }
        } else {
            Write-Output "$($vm.Name) is not powered on. Skipping ..."
        }
    } catch {
        Write-Error "Error processing $($vm.Name): $_"
    }
}

# Disconnect from the vCenter Server
Disconnect-VIServer -Server $server -Confirm:$false -Force

Another option is Using vSphere Web Client:

1. Navigate to the VM: In vSphere Web Client, navigate to the virtual machine you want to configure.
2. VM Options: Go to the VM’s settings, and under “VM Options,” look for “VMware Tools.”
3. Upgrade Settings: Find the setting labeled something like “Check and upgrade Tools during power cycling” and enable it.
4. Save: Save the changes and exit.

# Connect to the vCenter Server
Connect-VIServer -Server your_vcenter_server -User your_username -Password your_password

# Get the VM object
$vm = Get-VM -Name "Your_VM_Name"

# Configure VMware Tools upgrade at power cycle
$vm | Get-AdvancedSetting -Name "tools.upgrade.policy" -ErrorAction SilentlyContinue | Set-AdvancedSetting -Value "upgradeAtPowerCycle" -Confirm:$false

# Disconnect from the vCenter Server
Disconnect-VIServer -Server your_vcenter_server -Confirm:$false

Notes:

• Replace your_vcenter_server, your_username, your_password, and Your_VM_Name with your actual vCenter server details and the VM name.
• After setting this, VMware Tools will be upgraded the next time the VM is rebooted.
• Make sure to inform the relevant parties that the VM will be experiencing a reboot, especially if it hosts critical applications or services.
• Ensure the reboot and VMware Tools upgrade don’t interfere with the normal operation of applications and services on the VM.
• It is always a good practice to have a backup or snapshot of the VM before performing any upgrade.