The desired result from this script is to find out the PowerShell version on a list of hosts. I would like to handle the exception when the remote machine is down or does not have remoting enabled. However, the catch does not appear to be entered. Just the standard red flaming error message from PowerShell appears.
What do I need to do to catch the exception?
X:\Scripts\PSAutomation> Get-Content .\get-versions.ps1
server_list = #(
'CAPPY'
)
$server_list |
ForEach-Object {
Try {
Invoke-Command -ComputerName $_ {$PSVersionTable.PSVersion}
}
Catch
{
Write-Host "Failed to connect to $_"
}
}
X:\Scripts\PSAutomation> .\get-versions.ps1
[CAPPY] Connecting to remote server CAPPY failed with the following error message : WinRM cannot process the
request. The following error occurred while using Kerberos authentication: Cannot find the computer CAPPY. Verify
that the computer exists on the network and that the name provided is spelled correctly. For more information, see
the about_Remote_Troubleshooting Help topic.
+ CategoryInfo : OpenError: (CAPPY:String) [], PSRemotingTransportException
+ FullyQualifiedErrorId : NetworkPathNotFound,PSSessionStateBroken
Just set the ErrorAction for that call to stop:
Invoke-Command -ComputerName "sdf" {$PSVersionTable.PSVersion} -ErrorAction Stop
Related
I created a short PowerShell scrtipt in order to import a .reg file (an ODBC) to another server session.
I faced to this warning/issue.
The message is this (below):
The operation completed successfully.
+ CategoryInfo : NotSpecified: (The operation completed successfully.:String) [], RemoteException
+ FullyQualifiedErrorId : NativeCommandError
+ PSComputerName : MYSERVERNAME
NotSpecified: (:) [], RemoteException
The script, install without problem the .reg file, but constantly I get the message.
This is my code:
#PARAMETERS - Variables
$Serverlist = Get-Content C:\ServerList.txt
try
{
Foreach ($ServerName in $Serverlist)
{
$session = New-PSSession -ComputerName $servername
Write-Host -Foregroundcolor Green "Copying ODBC Driver for $servername"
$copy_cmd = "C:\MYFILE.reg"
Copy-Item $copy_cmd \\$servername\C$\ -recurse -force;
Write-Host -Foregroundcolor Green "ODBC Successfully copied on $servername"
#$session = New-PSSession -ComputerName $servername
Invoke-Command -Session $session -ScriptBlock {
#Start-Process
reg import C:\CopiedFile.reg #This line generate the message
Write-Host -Foregroundcolor Green "ODBC was installed
}
catch
{
Write-Host "ERROR" -Foregroundcolour Red
exit
}
I tried to incapsulate the Invoke-Command or reg import in to try - catch statement, but the message still appear. I used another command, instead reg import, but the nothing change.
I can use this command line, but I would like to catch the error.
Write-Host -Foregroundcolor Green "ODBC is installed " } ##-ErrorAction SilentlyContinue
There is any way to get the eventually error or handle the message.
Thanks in advance.
If the try block does not generate a terminating error, it will not move into the Catch block. This is controlled by -ErrorAction parameter. So you can set
Invoke-Command Session $session -ScriptBlock {} -ErrorAction Stop
This will cause the Invoke-Command Cmdlet to generate terminating errors(if any error occurs) allowing catch block to execute.
It is not going to "catch" block as part of invoke-command for the incorrect host using powershell
$server= #("correcthost","Incorrecthost")
foreach($server in $server)
{
Try{
Invoke-Command -ComputerName $server -ArgumentList $server -ScriptBlock {
$serverk=$args[0]
write-host $serverk
}
}
Catch
{
write-host "error connecting to $serverk"
}
}
I expect the catchblock getting executed as i am trying to incorrect host
but the actual output is not printing catch block
There are two issues. First, the variable $serverk is out of scope in the catch block. It's being used only on the remote computer, so it doesn't exist - or have value - on the local system.
Debugging any Powershell script should always start with turning on the strict mode, so warnings about uninitialized variables are generated. Like so,
Set-StrictMode -Version 'latest'
...<code>
The variable '$serverk' cannot be retrieved because it has not been set.
At line:12 char:41
+ write-host "error connecting to $serverk"
+ ~~~~~~~~
+ CategoryInfo : InvalidOperation: (serverk:String) [], RuntimeException
+ FullyQualifiedErrorId : VariableIsUndefined
The fix is easy, just refer to $server that's the variable used in iterating $servers.
The second issue is caused by ErrorAction, or to be specific, not declaring one. Add -ErrorAction Stop to Invoke-Command and process the exception in catch block like so,
catch{
write-host "error connecting to $server`: $_"
}
error connecting to doesnotexist: [doesnotexist] Connecting to remote server doesnotexist failed...
I have created a basic script to add a PC to the domain. Although this works there is room for error, and I want to put in some error handling.
do {
Add-Computer -DomainName $Domain -Credential(get-credential)
} while (!$?)
Using !$? runs the while loop while the last command is not successful.
However, there are various errors that return. Whether the PC is off the network, incorrect user ID or password, or domain specification, I want to be able to handle those errors and display something meaningful.
One of the errors returned
Add-Computer : This command cannot be executed on target computer('PCName') due to
following error: Logon failure: unknown user name or bad password.
At line:1 char:13
+ Add-Computer <<<< -DomainName $Domain -Credential(get-credential);
+ CategoryInfo : InvalidOperation: (PCNAME:String) [Add-Computer], InvalidOperationException
+ FullyQualifiedErrorId : InvalidOperationException,Microsoft.PowerShell.Commands.AddComputerCommand
Working with error handlers in lets say VBA, an error ID is given, and using if statements you can do something with it.
The FullyQualifiedErrorID in the error above is the same across all errors received for different reasons, so I do not believe I can use that.
How can I capture the specific error "Logon failure: unknown user name or bad password." or other errors and display a meaningful message so the admin can take appropriate action?
If nothing else you should be able to use the error message for distinguishing between errors:
do {
$joined = $true
$cred = Get-Credential
try {
Add-Computer -DomainName $Domain -Credential $cred -ErrorAction Stop
} catch {
$joined = $false
switch -regex ($_.Exception.Message) {
'.*unknown user name.*' { ... }
'.*domain does not exist.*' { ... }
...
default { 'Unexpected error' }
}
}
} until ($joined)
Note that you'll need to set the error action to Stop (-ErrorAction Stop), because otherwise the errors would be non-terminating and thus not catchable.
Use it with the -ErrorAction parameter:
Add-Computer ... -ErrorAction SilentlyContinue -ErrorVariable computerError
The ErrorVariable is an array, so the resulting error will be stored in:
$computerError[0]
To use the same variable over and over again, use a + in front of the var name:
Add-Computer -ErrorVariable +manyErrors
And the last error will always be:
$manyErrors[$manyerrors.count - 1]
To get the last error code if it has a corresponding Win32 error code then run the following
$manyErrors[$manyerrors.count - 1].Exception.InnerException.NativeErrorCode
And then if you gather the potential error codes you could do the following
if ($manyErrors[$manyerrors.count - 1].Exception.InnerException.NativeErrorCode -eq 1)
{
Write-Host error happened
}
elseif ($manyErrors[$manyerrors.count - 1].Exception.InnerException.NativeErrorCode -eq 2)
Write-Host other error happened
}
I want to output a custom error message to a log, when a GWMI query fails. I can catch the exception, but apparently only the last one, because the output in my error file only has the name of the last computer in the list. I am using a list of computers I know do not have WMI enabled. There should be an entry for each one.
I have a list of domain computers in a text file, each on a single line, no trailing characters. I loop through the file to get network information, using GWMI. Some of the computers do not have WMI enabled, and I want to know which ones. My current script just throws a:
gwmi : The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)
At line:12 char:17
+ $base = gwmi win32_networkadapterconfiguration -computername $comp | whe ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (:) [Get-WmiObject], COMException
+ FullyQualifiedErrorId : GetWMICOMException,Microsoft.PowerShell.Commands.GetWmiObjectCommand
whenever it loops through a machine that does not have wmi enabled.
This does not identify the computer that threw the exception. What I would like is for every time the RPC server is unavailable... error is thrown, for a custom error message to be written to a log with the name of the computer that threw the exception.
My script:
$computers = Get-Content -path f:\scripts\docs\computer_list_test.txt
if (F:\scripts\wmi_mac_output.txt){
rm F:\scripts\wmi_mac_output.txt
}
foreach ($comp in $computers) {
try
{
$base = gwmi win32_networkadapterconfiguration -computername $comp -ErrorAction Stop | where {$_.dnsdomain -eq "mydomain.com"}
$machine = $base.DNSHostName
$mac = $base.MACAddress
$ip = $base.IPAddress
"<COMPUTER>`n`tname: $machine`n`tMAC: $mac`n`tIP: $ip`n</COMPUTER>" | Out-File F:\scripts\wmi_mac_output.txt
}
catch [Exception]
{
if ($_.Exception.GetType().Name -eq "COMException")
{
"$comp has no winrm" > f:\scripts\docs\error.txt
}
}
}
Thank you.
I can catch the exception, but apparently only the last one, because the output in my error file only has the name of the last computer in the list.
The issue is that the error.txt is being overwritten instead of appended.
"$comp has no winrm" > f:\scripts\docs\error.txt
Change to:
"$comp has no winrm" >> f:\scripts\docs\error.txt
I have a problem with the catch command. I have the following script I'm trying to process:
Try
{
Add-Computer -DomainName "MyDomain.Dom" -Credential $DomainCred -PassThru -ErrorAction Stop
}
Catch [System.InvalidOperationException]
{
"Your computer is unable to contact the domain"
}
Every time I run this though I am not getting anything in the catch block. Here is the error reported that I get from the script:
PSMessageDetails :
Exception : System.InvalidOperationException: This command cannot be executed on target computer('') due to following error: The specified domain either does not exist or could not
be contacted.
TargetObject :
CategoryInfo : InvalidOperation: (MYPC:String) [Add-Computer], InvalidOperationException
FullyQualifiedErrorId : InvalidOperationException,Microsoft.PowerShell.Commands.AddComputerCommand
ErrorDetails :
InvocationInfo : System.Management.Automation.InvocationInfo
PipelineIterationInfo : {0, 1}
Any ideas?
A working solution (thanks to PK and Patrick for their combined contributions):
Try
{
Add-Computer -DomainName "MyDomain.Dom" -Credential $DomainCred -PassThru -ErrorAction Stop
}
Catch [System.Management.Automation.RuntimeException]
{
"Your computer is unable to contact the domain"
}
Try catching System.Management.Automation.RuntimeException instead of System.InvalidOperationException.
Try
{
Add-Computer -DomainName "MyDomain.Dom" -Credential $DomainCred
}
Catch [System.Management.Automation.RuntimeException]
{
'Error: {0}' -f $_.Exception.Message
}
Add "-ErrorActionPreference Stop" to your cmdlet.
For instance,
Add-Computer -DomainName "MyDomain.Dom" -Credential $DomainCred -EA Stop
There does seem to be a few inconsistencies with the ways that different cmdlets process errors, especially those "add-on" cmdlets like the Active Directory ones. However, I think the basic idea is that PowerShell catch only catches terminating errors, of which your exception above isn't by default. So by using -EA Stop you're forcing it be a terminating error, which triggers the catch block.
Here's Ed Wilson on the subject: Write PowerShell Functions That Accept Pipelined Input
I was able to get this to work:
Try
{
Add-Computer -DomainName "MyDomain.Dom" -Credential $DomainCred -PassThru -ErrorAction Stop
}
Catch
{
"Your computer is unable to contact the domain"
}
-PassThru on the Add-Computer command returns the results of the command to the shell.
-ErrorAction Stop tells PowerShell to stop when it encounters an error; this suppresses the error output you were seeing.
FullName
--------
System.Management.Automation.RuntimeException
The object of type "Microsoft.PowerShell.Commands.Internal.Format.FormatStartData" is not valid or not in the correct sequence. This is likely caused by a user-specified "f
ormat-list" command which is conflicting with the default formatting.
+ CategoryInfo : InvalidData: (:) [out-lineoutput], InvalidOperationException
+ FullyQualifiedErrorId : ConsoleLineOutputOutOfSequencePacket,Microsoft.PowerShell.Commands.OutLineOutputCommand
Putting the -Passthru on it allowed it to catch the error.