Re-IP’ing ESXi hosts in vCenter using a PowerShell script involves several steps and should be handled with caution, as it can disrupt the virtualized environment. The following script assumes you have VMware PowerCLI installed and connected to your vCenter server.

Before running the script, ensure you have a backup of your current configuration, and understand the implications of re-IP’ing your ESXi hosts.

# Connect to vCenter server
Connect-VIServer -Server YOUR_VCENTER_SERVER -User YOUR_USERNAME -Password YOUR_PASSWORD

# Define the old and new IP addresses
$oldIP = "OLD_IP_ADDRESS"
$newIP = "NEW_IP_ADDRESS"
$subnetMask = "NEW_SUBNET_MASK"
$gateway = "NEW_GATEWAY"

# Retrieve all ESXi hosts managed by vCenter
$esxiHosts = Get-VMHost

# Reconfigure network settings for each ESXi host
foreach ($esxiHost in $esxiHosts) {
    Write-Host "Reconfiguring network settings for $($esxiHost.Name)..."
    $esxiHostNic = Get-VMHostNetworkAdapter -VMHost $esxiHost | Where-Object { $_.Type -eq "Management" }

    # Set new IP address, subnet mask, and gateway
    $esxiHostNic | Set-VMHostNetworkAdapter -IP $newIP -SubnetMask $subnetMask -Gateway $gateway -Confirm:$false

    # Test the new connection and make sure it is responding
    if (Test-Connection -ComputerName $newIP -Count 1 -Quiet) {
        Write-Host "ESXi host $($esxiHost.Name) has been reconfigured successfully."
    } else {
        Write-Host "Failed to reconfigure ESXi host $($esxiHost.Name). Please verify the new network settings manually."
    }
}

# Disconnect from vCenter server
Disconnect-VIServer -Server $null

Replace the placeholders YOUR_VCENTER_SERVER, YOUR_USERNAME, YOUR_PASSWORD, OLD_IP_ADDRESS, NEW_IP_ADDRESS, NEW_SUBNET_MASK, and NEW_GATEWAY with appropriate values.

This script will loop through all ESXi hosts managed by vCenter, reconfigure the network settings for the management interface with the new IP address, subnet mask, and gateway, and then test the new connection to ensure it is responsive.

Again, exercise extreme caution when using this script, and always have a backup and a rollback plan ready before making any changes to your production environment.