On Fri, Oct 07, 2016 at 08:38:07PM +0100, 'Viktor Bachraty' via ganeti-devel
wrote:
> Add a side effect to StartInstance on Xen hypervisor that restores the
> Xen configuration in case it is missing. This is a common failure
> scenario during migrations. The generic backend checks if the instance
> is running and queries the hypervisor about it's state. If it needs
> recovery, the backend gathers the associated block devices and calls
> RestoreInstance in the same manner as if it would call StartInstance in
> case the instance wasn't already running.
LGTM, except for the nits below (which don't change functionality).
> + if instance_info and not _IsInstanceUserDown(instance_info):
> + logging.info("Instance '%s' already running, not starting",
> instance.name)
> + if hyper.VerifyInstance(instance):
> + return
> + logging.info("Instance '%s' needs fixup", instance.name)
"Instance '%s' hypervisor config out of date. Restoring." maybe?
> + def VerifyInstance(self, instance): # pylint: disable=R0201,W0613
Nit: I think this is a bit misleading: it's not quite about the running instance
state, it's about the config on disk. How about VerifyHypervisorConfig?
> + """Verify if running instance is in correct state.
Nit: has correct configuration
> + @param instance: instance to stop
Nit: s/to stop/to verify/
> + def RestoreInstance(self, instance, block_devices):
Nit: WriteHypervisorConfig, maybe?
> + @param instance: instance to stop
Nit: s/to stop/to write/
> + def VerifyInstance(self, instance):
> + """Verify if running instance is in correct state.
> +
> + @type instance: L{objects.Instance}
> + @param instance: instance to stop
As for hv_base.
> + def RestoreInstance(self, instance, block_devices):
> + """Fixup running instance's state.
> +
> + @type instance: L{objects.Instance}
> + @param instance: instance to stop
As for hv_base.
> def StartInstance(self, instance, block_devices, startup_paused):
> """Start an instance.
>
> + @type instance: L{objects.Instance}
> + @param instance: instance to stop
Nit: s/to stop/to start/
