Thanks for responding,

On Mon, Dec 20, 2021 at 9:59 PM Nathanaël Blanchet <blanchet@abes.fr> wrote:

Adding the devel list since question is more about extending oVirt
...

The idea is to use the stop_reason element into the vm xml definition. But after hours, I realized that this element is writed to the vm definition file only after the VM has been destroyed.

So you want to run the clean hook only if stop reason == "clean"?

I think the way to integrate hooks is to define a custom property
in the vm, and check if the property was defined in the hook.

For example how the localdisk hook is triggered:

def main():
    backend = os.environ.get('localdisk')
    if backend is None:
        return
    if backend not in [BACKEND_LVM, BACKEND_LVM_THIN]:
        hooking.log("localdisk-hook: unsupported backend: %r" % backend)
        return
    ...

The hook runs only if the environment variable "localdisk" is defined
and configured properly.

vdsm defines the custom properties as environment variables.

On the engine side, you need to add a user defined property:

     engine-config -s UserDefinedVMProperties='localdisk=^(lvm|lvmthin)$'

And configure a custom property with one of the allowed values, like:

    localdisk=lvm

See vdsm_hooks/localdisk/README for more info.

If you want to control the cleanup, by adding a "clean" stop reason only when
needed, this will not help, and vdsm hook is probably not the right way
to integrate this.

If your intent is to clean a vm in some special events, but you want
to integrate
this in engine, maybe you should write an engine ui plugin?

The plugin can show the running vms, and provide a clean button that will
shut down the vm and run your custom code.

But maybe you don't need to integrate this in engine, and having a simple
script using ovirt engine API/SDK to shutdown the vm and run the cleanup
code.

Nir

I will sum up my initial question: Is there any way to get the value of "stop_reason" (value of the field in the UI) so as to reuse this variable into a vdsm hook?

Thank you

-- 
Nathanaël Blanchet

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