WSL2 does not keep running since Version 0.60.0

[Seeky90]

Version

Version 10.0.22000.739

WSL Version

• WSL 2
• WSL 1

Kernel Version

5.10.102.1

Distro Version

Ubuntu-20.04

Other Software

WSL Version 60.0 and higher

Repro Steps

To start some services I created a script and added it to the event scheduler. It starts sshd and cron.
After the start of the system, if I am fast (2-3 minutes) I can observe that the script has been run.

After waiting a bit WSL has been shut down and is restarted when I open the terminal. Then the services do not run.

For simplicity follow these repro steps:
Create a task scheduler task:

<?xml version="1.0" encoding="UTF-16"?> <Task version="1.2" xmlns="http://schemas.microsoft.com/windows/2004/02/mit/task"> <RegistrationInfo> <Date>2022-02-17T07:48:10.6191908</Date> <Author>username</Author> <URI>\test</URI> </RegistrationInfo> <Triggers /> <Principals> <Principal id="Author"> <UserId>S-1-5-21-2139355670-3375578443-2995265674-8217</UserId> <LogonType>InteractiveToken</LogonType> <RunLevel>HighestAvailable</RunLevel> </Principal> </Principals> <Settings> <MultipleInstancesPolicy>IgnoreNew</MultipleInstancesPolicy> <DisallowStartIfOnBatteries>false</DisallowStartIfOnBatteries> <StopIfGoingOnBatteries>true</StopIfGoingOnBatteries> <AllowHardTerminate>true</AllowHardTerminate> <StartWhenAvailable>false</StartWhenAvailable> <RunOnlyIfNetworkAvailable>false</RunOnlyIfNetworkAvailable> <IdleSettings> <StopOnIdleEnd>true</StopOnIdleEnd> <RestartOnIdle>false</RestartOnIdle> </IdleSettings> <AllowStartOnDemand>true</AllowStartOnDemand> <Enabled>true</Enabled> <Hidden>false</Hidden> <RunOnlyIfIdle>false</RunOnlyIfIdle> <WakeToRun>false</WakeToRun> <ExecutionTimeLimit>PT72H</ExecutionTimeLimit> <Priority>7</Priority> </Settings> <Actions Context="Author"> <Exec> <Command>C:\Windows\System32\wsl.exe</Command> <Arguments>--shutdown</Arguments> </Exec> <Exec> <Command>C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe</Command> <Arguments>-windowstyle hidden -ExecutionPolicy Bypass C:\Users\username\test.ps1</Arguments> </Exec> </Actions> </Task>

Add into the Powershell script C:\Users\username\test.ps1:
bash.exe -c "sudo /opt/wsl-init.sh

Into /opt/wsl-init.sh add:
service cron start

Expected Behavior

Since the service is running all the time I expect the WSL session to stay active.

Actual Behavior

Since version 60 of WSL this does not work anymore. After a few minutes wsl --list --verbose shows that the WSL instance has been stopped.

Diagnostic Logs

#8611
WslLogs-2022-07-22_07-29-04.zip

[OneBlue]

@Seeky90: by design the WSL2 VM stops if inactive after 60 seconds.

You can change this behavior by setting:

[wsl2]
vmIdleTimeout=-1

In %userprofile%/.wslconfig. (-1 means that the VM never times out).

[NotTheDr01ds]

@OneBlue Just to be clear, according to the issue above, the instance shouldn't be inactive. If cron is running, which the issue states it is, then the instance shouldn't self-terminate. The instance should only self-terminate when there are no processes running under init. That's been the design since the early WSL1 days, right?

@Seeky90 Does this only happen when run via a Scheduled Task? If so, probably better to list out the task settings in a bulleted list that's more "human readable" than the XML ;-).

Also, you might want to ask this over on Ask Ubuntu or Super User. I suspect something in your script rather than a change in WSL behavior, but I'd be happy to try to reproduce if you can make the steps more readable. I haven't tried a scheduled task myself with the "Preview", personally.

I do see you have a custom kernel running which you might want to try disabling as a normal troubleshooting step.

[Seeky90]

Thanks for the clarification @NotTheDr01ds . Thats just as it is. @OneBlue You might be correct about the timeout. For some reason the started tasks do not run under init, please see below.

I have done some tests and am quite sure that a bug leads to this behavior. I am not sure if it is due to how systemd behaves or how to wsl behaves.

Please try to reproduce it yourself:

Create a Schedules Task, I have added a file wich you can import with powershell using:
Register-ScheduledTask -xml (Get-Content -Raw WSL-Test.xml) -TaskName WSL-Test

Place the file wsl-test.ps1 in your user directory.

Create a file /opt/wsl-test.sh
Make it executable.

Add the following content for auto shutdown:
service udev start & service ssh start

OR

Add the following content for no shutdown:
service udev start service ssh start

Add the /opt/wsl-test.sh to /etc/sudoers as NOPASSWD

When I start the task from the task scheduling by hand I can see that in case I use the & on one service, both services are not run under init anymore, which leads to the auto shutdown. When the & is omitted both services run under init. I'd expect only the one with & to run in background, not both.
When I start the task from the terminal both processed are run unter init, no matter of the &.

wsl-test.zip

[OneBlue]

@Seeky90: What exactly do you mean by the the started tasks do not run under init ? Can you share a screenshot of that htop looks like in this scenario ?

[Seeky90]

Hey @OneBlue

In case I have the following in my init file (Run from Task Scheduler)

#!/bin/bash

service ssh start
service udev start &
service cron start
service atd start
/opt/setIP.sh
echo $(date) >> /tmp/wsl-init-date

then ps will looks like this when started using a scheduled task:

Shutting down the WSL, starting it by hand and running the same script with sudo gives me this:

After I created this ticket with your hint about the timeout (Which did not work for me, will create a ticket for this)
I changed the script to the following:

#!/bin/bash

service ssh start
service cron start
service atd start
/opt/setIP.sh
echo $(date) >> /tmp/wsl-init-date
nohup service udev start

then the result looks as expected:

[Seeky90]

@Seeky90: by design the WSL2 VM stops if inactive after 60 seconds.

You can change this behavior by setting:

[wsl2]
vmIdleTimeout=-1

In %userprofile%/.wslconfig. (-1 means that the VM never times out).

As @NotTheDr01ds explained here, this is not a solution to the issue that the VM turns off even though there is still something running: #8659

[hammadrauf]

I am able to keep WSL2 running in background on Windows 11, using the following Power Shell 7 script. Also tried it from Task Schedular, works as expected.
The script is getting the IP address of the WSL instance, Then it runs a never ending background process. It then Forwards a few ports to the Host computer using the IP address from previous step. For Port forwarding (netsh) "IP Helper" service should be running.

Script is executed like: "C:\Program Files\PowerShell\7\pwsh.exe" -ExecutionPolicy Bypass -File "C:\scripts\wsl2\start-wsl-forward-ports.ps1"

Script file is given below:

$wsl_ip = (wsl -d "Ubuntu-22.04" --shell-type login hostname -I).split(" ")[0]
Write-Host "WSL Machine IP: ""$wsl_ip"""
wsl -d "Ubuntu-22.04" --shell-type login tail -n 1 -f /dev/null &
netsh interface portproxy add v4tov4 listenport=4505 connectport=32377 connectaddress=$wsl_ip
netsh interface portproxy add v4tov4 listenport=4506 connectport=32378 connectaddress=$wsl_ip
netsh interface portproxy add v4tov4 listenport=8092 connectport=32380 connectaddress=$wsl_ip
Write-Host "Completed - Start WSL and port forwarding..."

--

[Seeky90]

@hammadrauf Your test case is different from mine.

As mentioned above it gets caused by a special combination of commands:

This will cause it:

    #!/bin/bash

    service ssh start
    service udev start &
    service cron start
    service atd start

This is totally fine:

    #!/bin/bash

    service ssh start
    service cron start
    service atd start
    nohup service udev start

[hammadrauf]

Maybe the last command in script should be the background job...... I had issues also till I made the last command in WSL to be the background job.