How to make wsl2 alive in the background

[amuncx]

Wsl2 will automatically shut down when the terminal is closed.I need it alive in the background.
Is there such a function in the configuration file, so that wsl2 can only be closed manually by running wsl --shutdown. If not, would you consider adding this feature.

[elsaco]

@amunv WT has a headless feature (microsoft/terminal#14944) that might keep your WSL instance running.

[amuncx]

@amunv WT has a headless feature (microsoft/terminal#14944) that might keep your WSL instance running.

I don't understand it a bit, should I add "allowHeadless": true in setting.json
As he said, there is no wt --headless or wt --hidden.

[aki-k]

@amunv You can make it stay running with this setup: #10157 (comment)

[OneBlue]

Thank you for reporting this @amunv. You can force WSL2 to keep running with:

[wsl2]
vmIdleTimeout=-1

in %userprofile%/.wslconfig

[aki-k]

vmIdleTimeout=-1

I'm not sure why this is not documented at https://learn.microsoft.com/en-us/windows/wsl/wsl-config

It just says

The number of milliseconds that a VM is idle, before it is shut down. Only available for Windows 11.

[amuncx]

Thank you for reporting this @amunv. You can force WSL2 to keep running with:

[wsl2]
vmIdleTimeout=-1

in %userprofile%/.wslconfig

This is not what I need. About ten seconds after closing the terminal, wsl enters the suspended state. At this time, the docker application cannot be used normally, and the system memory usage is reduced. The "vmIdleTimeout" option controls the survival time of vmmemwsl after wsl is suspended. During this time, when WT is turned on, wsl will run normally. I don't need this suspend state and control the time after suspend. What I need is that wsl suspend after about ten seconds, disable this suspend.
[wsl2] vmIdleTimeout=120000 memory=2GB processors=2

[OneBlue]

Thank you for reporting this @amunv. You can force WSL2 to keep running with:

[wsl2]
vmIdleTimeout=-1

in %userprofile%/.wslconfig

This is not what I need. About ten seconds after closing the terminal, wsl enters the suspended state. At this time, the docker application cannot be used normally, and the system memory usage is reduced. The "vmIdleTimeout" option controls the survival time of vmmemwsl after wsl is suspended. During this time, when WT is turned on, wsl will run normally. I don't need this suspend state and control the time after suspend. What I need is that wsl suspend after about ten seconds, disable this suspend. [wsl2] vmIdleTimeout=120000 memory=2GB processors=2

Yes, that's exactly what vmIdleTimeout=-1 does. When set to -1, the WSL2 VM will never time out and WSL2 will keep running until wsl.exe --shutdown is called.

[aki-k]

@OneBlue Your solution does not work. I put

[wsl2]
vmIdleTimeout=-1

into C:\Users\aki\.wslconfig and restarted WSL 2 VM.

Then I installed apache2 in WSL 2 VM

sudo apt-get install apache2
sudo systemctl enable --now apache2

I can see in "ss -tulpan | grep apache2" that it's listening on port 80.

Then I load http://localhost/ on Windows host side Firefox and the Apache2 Ubuntu Default Page opens.

I exit from WSL 2 VM with "exit".

I have this loop running in another CMD prompt

for /l %i in () do @( tasklist | findstr /i "vm wsl" & ping -n 3 127.0.0.1 >nul & echo --- )

It lists the processes matching "vm" and "wsl".

When I exit WSL 2 VM, the 2 wslhost.exe processes end after a short while.

The Apache2 Ubuntu Default Page on the Windows host side Firefox stops responding at the same time.

[elsaco]

@aki-k vmIdleTimeout = -1 does keep the VM running after exiting the shell. You stated adding the setting then restarted WSL 2 VM. Make sure you restart the WSL service not only the VM. Run wsl --shutdown for the setting to take effect.

[aki-k]

and restarted WSL 2 VM.

means I exited the WSL 2 VM and ran wsl --shutdown in CMD prompt. Do I also need to restart lxssmanager?

[aki-k]

After "exit" -> 2 wslhost.exe processes stop after a short while -> "bash" -> I can use "ps auxwwf | grep apache2" to see the process start-up time and they just started up. So the WSL 2 instance also started up again.