[ZBX-19278] Powershell script run via system.run in Agent 2 not executing correctly Created: 2021 Apr 23  Updated: 2022 Jul 18

Status: Open
Project: ZABBIX BUGS AND ISSUES
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Incident report Priority: Trivial
Reporter: Shane Arnold Assignee: Zabbix Support Team
Resolution: Unresolved Votes: 1
Labels: agent2, nowait, passive, powershell
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Attachments: PNG File image-2021-04-23-12-21-48-693.png     PNG File image-2021-04-23-12-23-52-839.png     PNG File image-2021-04-23-12-26-41-260.png     PNG File image-2021-04-23-12-29-43-397.png     PNG File image-2021-04-23-12-38-15-204.png     PNG File image-2021-04-23-13-15-58-443.png    

 Description   

Executing a system.run command as shown in the example below does not execute correctly when nowait parameter is set.

Removing the nowait parameter allows the script to execute correctly.

Steps to reproduce:

Create passive check, key "system.run["powershell.exe -executionpolicy bypass -File \"C:\Program Files\Zabbix Agent 2\Scripts\Get-PendingReboot.ps1\" check",nowait]"

Execute check either via "Execute" or using zabbix_get

Confirm that command was received and excuted on Agent 2 (DebugLevel=4)

2021/04/23 12:23:34.796755 received passive check request: 'system.run[powershell.exe -executionpolicy bypass -File "C:\Program Files\Zabbix Agent 2\Scripts\Get-WindowsUpdateLastInstalled.ps1" check,nowait]' from '192.168.10.100'
2021/04/23 12:23:34.797732 [1] processing update request (1 requests)
2021/04/23 12:23:34.797732 [1] adding new request for key: 'system.run[powershell.exe -executionpolicy bypass -File "C:\Program Files\Zabbix Agent 2\Scripts\Get-WindowsUpdateLastInstalled.ps1" check,nowait]'
2021/04/23 12:23:34.798731 [1] created direct exporter task for plugin 'SystemRun' itemid:0 key 'system.run[powershell.exe -executionpolicy bypass -File "C:\Program Files\Zabbix Agent 2\Scripts\Get-WindowsUpdateLastInstalled.ps1" check,nowait]'
2021/04/23 12:23:34.798731 executing direct exporter task for key 'system.run[powershell.exe -executionpolicy bypass -File "C:\Program Files\Zabbix Agent 2\Scripts\Get-WindowsUpdateLastInstalled.ps1" check,nowait]'
2021/04/23 12:23:34.799731 [SystemRun] Executing command:'powershell.exe -executionpolicy bypass -File "C:\Program Files\Zabbix Agent 2\Scripts\Get-WindowsUpdateLastInstalled.ps1" check'
2021/04/23 12:23:34.808731 executed direct exporter task for key 'system.run[powershell.exe -executionpolicy bypass -File "C:\Program Files\Zabbix Agent 2\Scripts\Get-WindowsUpdateLastInstalled.ps1" check,nowait]'
2021/04/23 12:23:34.812733 sending passive check response: '1' to '192.168.10.100'

Expected output should be zabbix_sender called to send back a value (and output to a log file at each function/step to show that script has been run).

No file is created

Expected

A system.run item with a nowait command should work as expected.

 Comments   
Comment by Shane Arnold [ 2021 Apr 23 ]

Extra notes:

  • Path provided to powershell using -File contains a space.
  • Windows PowerShell eventlog doesn't show any execution for this command (however does correctly show other active check items, such as 'powershell.exe Write-Host (Test-Connection $env:COMPUTERNAME -Count 1).IPV4Address'
zabbix_get -s 192.168.10.34 -k system.run[powershell.exe -executionpolicy bypass -File "C:\Program Files\Zabbix Agent 2\Scripts\Get-WindowsUpdateLastInstalled.ps1" check,nowait] 
zabbix_get [929699]: invalid option -- e

 

Attempting to escape the quotes so that the path is correctly provided to powershell results in the same

root@ITDVZX001:~# zabbix_get -s 192.168.10.34 -k system.run[powershell.exe -executionpolicy bypass -File \"C:\Program Files\Zabbix Agent 2\Scripts\Get-WindowsUpdateLastInstalled.ps1\" check,nowait]
zabbix_get [930300]: invalid option -- e

 

Correcting the key to single-quote the powershell command works, however is not valid powershell (execution fails if this is run locally). Is received by Agent2. 

root@ITDVZX001:~# zabbix_get -s 192.168.10.34 -k system.run['powershell.exe -executionpolicy bypass -File \"C:\Program Files\Zabbix Agent 2\Scripts\Get-WindowsUpdateLastInstalled.ps1\" check',nowait]
1

 

Removing the escaping for the double-quotes should be valid powershell (but there is no execution of powershell from what I can tell). Is received by Agent2.

root@ITDVZX001:~# zabbix_get -s 192.168.10.34 -k system.run['powershell.exe -executionpolicy bypass -File "C:\Program Files\Zabbix Agent 2\Scripts\Get-WindowsUpdateLastInstalled.ps1" check',nowait]
1

 

Running the above valid command locally works, generates the Out-File as expected and correctly executes and sends the value

Comment by Dmitry Krupornitsky [ 2021 May 14 ]

Hello, Shane

 

It's really a complex thing to do if you try to use long shell commands (with special chars like " '  [ ] ) for system.run key.
If possible, I would recommend to use UserParameters on agent side to define such commands there.

When constructing such long system.rum key, first of all you have to follow item key syntax requirements:
https://www.zabbix.com/documentation/5.0/manual/config/items/item/key

So, all the data inside square brackets is highly recommended to enclose in double quotes. But, you have double quotes in shell command itself, so they must be escaped, manually: https://www.zabbix.com/documentation/5.0/manual/config/items/item/key#parameter_-_quoted_string

Does the problem persist? 

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