Compare Patch Levels across Multiple servers - arrays

Question

Hi all I was working on a script to compare a list of patch levels between multiple servers and show the list of patches missing on either of server. The script should compare between each server within the array and give the output i was trying using Get-Hotfix and also using compare-object to compare and get the server name evaluating $_.sideindicator -match "=>" and $_.sideindicator -match "<=".
can anyone please help further?
here's the code till now for four servers, if there are n number of servers i wanted the logic on how to proceed.
$array=#()
$serd1 = Get-HotFix -ComputerName serd1 | select -ExpandProperty hotfixid
$serd2 = Get-HotFix -ComputerName serd2 | select -ExpandProperty hotfixid
$serd3 = Get-HotFix -ComputerName serd3 | select -ExpandProperty hotfixid
$serd4 = Get-HotFix -ComputerName serd4 | select -ExpandProperty hotfixid
$check1 = Compare-Object -ReferenceObject $serd1 -DifferenceObject $serd2 -IncludeEqual | ?{$_.sideindicator -notmatch '=='}
$array += $check1 | ?{$_.sideindicator -match "=>"} | Select-Object #{l="HostName";e={"serd1"}},#{l="MissingPatches";e={$_.inputobject}}
$array += $check1 | ?{$_.sideindicator -match "<="} | Select-Object #{l="HostName";e={"serd2"}},#{l="MissingPatches";e={$_.inputobject}}
$check2 = Compare-Object -ReferenceObject $serd1 -DifferenceObject $serd3 -IncludeEqual | ?{$_.sideindicator -notmatch '=='}
$array += $check2 | ?{$_.sideindicator -match "=>"} | Select-Object #{l="HostName";e={"serd1"}},#{l="MissingPatches";e={$_.inputobject}}
$array += $check2 | ?{$_.sideindicator -match "<="} | Select-Object #{l="HostName";e={"serd3"}},#{l="MissingPatches";e={$_.inputobject}}
$check3 = Compare-Object -ReferenceObject $serd1 -DifferenceObject $serd4 -IncludeEqual | ?{$_.sideindicator -notmatch '=='}
$array += $check3 | ?{$_.sideindicator -match "=>"} | Select-Object #{l="HostName";e={"serd1"}},#{l="MissingPatches";e={$_.inputobject}}
$array += $check3 | ?{$_.sideindicator -match "<="} | Select-Object #{l="HostName";e={"serd4"}},#{l="MissingPatches";e={$_.inputobject}}
$check4 = Compare-Object -ReferenceObject $serd2 -DifferenceObject $serd3 -IncludeEqual | ?{$_.sideindicator -notmatch '=='}
$array += $check4 | ?{$_.sideindicator -match "=>"} | Select-Object #{l="HostName";e={"serd2"}},#{l="MissingPatches";e={$_.inputobject}}
$array += $check4 | ?{$_.sideindicator -match "<="} | Select-Object #{l="HostName";e={"serd3"}},#{l="MissingPatches";e={$_.inputobject}}
$check5 = Compare-Object -ReferenceObject $serd2 -DifferenceObject $serd4 -IncludeEqual | ?{$_.sideindicator -notmatch '=='}
$array += $check5 | ?{$_.sideindicator -match "=>"} | Select-Object #{l="HostName";e={"serd2"}},#{l="MissingPatches";e={$_.inputobject}}
$array += $check5 | ?{$_.sideindicator -match "<="} | Select-Object #{l="HostName";e={"serd4"}},#{l="MissingPatches";e={$_.inputobject}}
$check6 = Compare-Object -ReferenceObject $serd3 -DifferenceObject $serd4 -IncludeEqual | ?{$_.sideindicator -notmatch '=='}
$array += $check6 | ?{$_.sideindicator -match "=>"} | Select-Object #{l="HostName";e={"serd3"}},#{l="MissingPatches";e={$_.inputobject}}
$array += $check6 | ?{$_.sideindicator -match "<="} | Select-Object #{l="HostName";e={"serd4"}},#{l="MissingPatches";e={$_.inputobject}}
$array
The question is how to make this script work for random number of servers

Answer 1

This question is old but thought this might help out if anyone else finds this and thinks it is something they'd want to give a go.
Anyway, to meet the requirements stated here, see if this helps - let me know if anyone finds problems:
$Servers = "SERVER1", "SERVER2", "SERVER3", "SERVER4"
$MissingPatches=#()
$ServerPatches = New-Object 'object[]' $($Servers.Length)
for($i=0; $i -lt $($Servers.Length); $i++)
{
$ServerPatches[$i] = Get-HotFix -ComputerName $Servers[$i] | select -ExpandProperty hotfixid
}
for($i=0; $i -lt $($Servers.Length); $i++)
{
for($j=($i+1); $j -lt $($Servers.Length); $j++)
{
$Compare = Compare-Object -ReferenceObject $ServerPatches[$i] -DifferenceObject $ServerPatches[$j] -IncludeEqual | ?{$_.sideindicator -notmatch '=='}
$MissingPatches += $Compare | ?{$_.sideindicator -match "=>"} | Select-Object #{l="HostName";e={$Servers[$i]}},#{l="MissingPatches";e={$_.inputobject}}
$MissingPatches += $Compare | ?{$_.sideindicator -match "<="} | Select-Object #{l="HostName";e={$Servers[$j]}},#{l="MissingPatches";e={$_.inputobject}}
}
}
$MissingPatches = foreach($MissingPatch in $MissingPatches) {
if($($MissingPatch.MissingPatches) -ne "File 1")
{
$MissingPatch
}
}
$MissingPatches | ft -AutoSize
Going down this path I started thinking of potential improvements. So, if I have time I might rewrite and create a patch object that indicates on what server it is present and where it is missing for more detail of why a patch is indicated as "Missing".
When a patch is found on any server it is added to that array. A property of PresentOn will be updated with the server name it was found and the servers so far that didn't contain the patch can be added to a property of MissingOn, then checked continuously going forward. Then, a table of all patches can be displayed by these statuses vs. printing out only a "Missing" array. Could take some doing but might be worth the work. I'm also seeing this being a potentially costly script based on the number of patches in play and servers. But, if anyone else gets to it first (or finds flaws in the approach) let me know here!

Answer 2

This should work:
$servers = "one", "two", "three"
$array = #()
for ($i = 0; $i -lt ($servers.Count - 1); $i++)
{
$serd1 = Get-HotFix -ComputerName $servers[$i] | select -ExpandProperty hotfixid
$serd2 = Get-HotFix -ComputerName $servers[$i+1] | select -ExpandProperty hotfixid
$array += $check1 | ?{$_.sideindicator -match "=>"} | Select-Object #{l="HostName";e={"serd1"}},#{l="MissingPatches";e={$_.inputobject}}
$array += $check1 | ?{$_.sideindicator -match "<="} | Select-Object #{l="HostName";e={"serd2"}},#{l="MissingPatches";e={$_.inputobject}}
}
$array