Check with powershell if service is installed on multiple computers - powershell

Question

I'm looking for help with my script again :)
I have a script that will query list of servers to find if specific service is installed. This works fine. However, I know that there are some servers in my list that I don't have access to, or there are different credentials. How do I make this visible in output? Because I only get output that service is not installed, which is not true, I just don't have correct credentials.
$name = "BESClient"
$servers = Get-content C:\list.txt
function Confirm-WindowsServiceExists($name)
{
if (Get-Service -Name $name -Computername $server -ErrorAction Continue)
{
Write-Host "$name Exists on $server"
return $true
}
Write-Host "$name does not exist on $server"
return $false
}
ForEach ($server in $servers) {Confirm-WindowsServiceExists($name)}
Also, I'd like to have output formatted into the one line, e.g.:
Server1 Service running
Server2 Service not installed
Server3 no access
etc...
Thanks a lot for any help.

Answer 1

Here's an option which just displays the content of the error on failure:
function Confirm-WindowsServiceExists($name)
{
if (Get-Service -Name $name -Computername $server -ErrorAction SilentlyContinue -ErrorVariable WindowsServiceExistsError)
{
Write-Host "$name Exists on $server"
return $true
}
if ($WindowsServiceExistsError)
{
Write-Host "$server" $WindowsServiceExistsError[0].exception.message
}
return $false
}
As for the second part of the question #arco444 has described the correct approach.

Answer 2

Here's a WMI solution. Any errors you get from attempting to connect to remote computers will be caught with the try/catch blocks. The result of each operation will be stored to a custom object and added to the array that holds the results of all the operations.
$result = #()
$name = "BESClient"
$servers = Get-Content C:\list.txt
$cred = Get-Credential
foreach($server in $servers) {
Try {
$s = gwmi win32_service -computername $server -credential $cred -ErrorAction Stop | ? { $_.name -eq $name }
$o = New-Object PSObject -Property #{ server=$server; status=$s.state }
$result += ,$o
}
Catch {
$o = New-Object PSObject -Property #{ server=$server; status=$_.Exception.message }
$result += ,$o
}
}
$result | Format-Table -AutoSize
You should end up with something like this:
server state
------ -----
s1 running
s4 stopped
s2 The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)