[Avocado-devel] Bug: Once created VM object stays for all tests.

[Lukáš Doktor]

Hello Andrei,

if this happens than there is something really wrong because Avocado 
should re-create the VM for 2 reasons:

1) by default VMs are not shared between tests (can be enabled in cfg by 
setting `keep_guest_running = True` in `vt.setup` section)
2) when the params of the existing VM and the current params are 
different, it's recreated.

The (2) is checked in `virttest.env_process` on line `159` where it 
executes `vm.needs_restart`. The implementation of this function is 
defined mainly in `virttest.virt_vm` and unless overridden it uses the 
`virttest.virt_vm.make_create_command` to compare the original and the 
new command line to create the VM. If they are the same it reuses the VM 
(when (1) is enabled), otherwise it destroys the old VM and creates a 
new one.

The question is how different your machines are. The 
`make_create_command` does not compares the extra dynamic stuff like 
migration. More info about this can be found in 
`virttest.qemu_vm.create()` function (if using qemu as a backend).

Would you please (publicly or in private) share more details I might be 
able to identify why the machine is not being re-created.

Regards,
Lukáš

Dne 31.1.2017 v 18:15 Andrei Stepanov napsal(a):
> Hi.
>
> It seems that avocado-vt has a serious bug.
>
> Test case: run a few avocado-vt tests in a bunch. For example two tests.
> Test1 starts just right after Test2.
>
> Test1.
> Test2.
>
> Test1 & Test2 use the same name for VM in cartesian configs:
> vms = guest
>
> Other options for VM() objects are different, for example port VNC port,
> some device config, etc....
>
> The problem is that: KVM from Test2 uses VM() object that was created
> for Test1.
>
> For Test2:
> virttest/env_process.py:
>
> def preprocess_vm(test, params, env, name):
>
>       vm = env.get_vm(name)  <--- returns VM that was created for Test1.
>       create_vm == False
>
> It can be fixed by:
>
> diff --git a/virttest/env_process.py b/virttest/env_process.py
> index d05976e..7c08df4 100644
> --- a/virttest/env_process.py
> +++ b/virttest/env_process.py
> @@ -687,9 +687,8 @@ def preprocess(test, params, env):
>          vm = env[key]
>          if not isinstance(vm, virt_vm.BaseVM):
>              continue
> -        if vm.name <http://vm.name> not in requested_vms:
> -            vm.destroy()
> -            del env[key]
> +        vm.destroy()
> +        del env[key]
>
>      if (params.get("auto_cpu_model") == "yes" and
>              vm_type == "qemu"):
>
>
> Could you please confirm that bug exists in real?

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