I am trying to build a container which would include a custom scheduled task. This is my dockerfile:
FROM microsoft/windowsservercore
RUN schtasks /create /tn hello /sc daily /st 00:00 /tr "echo hello"
I get the following error:
ERROR: The task XML contains a value which is incorrectly formatted or out of range. (43,4):Task:
I get the same error also when attaching to a running default windows core container and running the command.
Needless to say, the command works well on standard windows 2016 server.
It seems like a bug in Windows containers, but I didn't find any known issue about it.
Appreciate any leads which may help figure out.
The issue has to do with the Container user. By default a scheduled task is created with the current user. It's possible the container user is a special one that the Scheduled Task command cannot parse into XML.
So you have to pass the user /ru
(and if needed the password /rp
) to the schtasks
command in a Windows Container.
This works
FROM microsoft/windowsservercore
RUN schtasks /create /tn "hellotest" /sc daily /tr "echo hello" /ru SYSTEM
It will run the command under the system account.
If you are a fan of Powershell (like me), you can use this
FROM microsoft/windowsservercore
SHELL ["powershell", "-Command", "$ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';"]
RUN $action = New-ScheduledTaskAction -Execute 'echo ""Hello World""'; \
$trigger = New-ScheduledTaskTrigger -Daily -At '1AM'; \
Register-ScheduledTask -TaskName 'Testman' -User 'SYSTEM' -Action $action -Trigger $trigger -Description 'Container Scheduled task test';