# Yusuf Ozturk, 2013
# http://www.yusufozturk.info
 
# Lets get our master Cluster Node, thats one of the most updated Cluster Node
$MasterNode = ((Get-Cluster | Get-ClusterNode | Select Name,@{label="HotFixes";expression={(Get-Hotfix -ComputerName $_.Name).HotFixID.Count}} | Sort HotFixes -Descending)[0]).Name
 
# Get Master Hotfix KBs and put them in a array
$MasterHotfixes = @((Get-Hotfix -ComputerName $MasterNode).HotFixID)
 
# Now we will use that master hotfixes to compare with others
$HotfixResults = (Get-Cluster | Get-ClusterNode | Select Name,@{label="Total Hotfixes";expression={(Get-Hotfix -ComputerName $_.Name).HotFixID.Count}},@{label="Missing Hotfixes";expression={$Hotfixes = @((Get-Hotfix -ComputerName $_.Name).HotFixID); $MissingHotfixes = (Compare-Object -ReferenceObject $MasterHotfixes -DifferenceObject $Hotfixes).InputObject; if ($MissingHotfixes) { $MissingHotfixes } else { $MissingHotfixes = "No missing updates"; $MissingHotfixes } }} | Sort Name)
 
# You can get hotfix IDs like this
$HotfixResults[0].'Missing Hotfixes'