On 08/21/2014 06:11 AM, Michal Witanowski wrote:
Hi all,
Is there any possibility (using libvirt C API or whatever else) to "propagate" shutdown events (reboot, halt, power off) to a host? The API seems to lack this functionality - there exists function virConnectDomainEventRegisterAny, but the virDomainEventStoppedDetailType enum does not distinguish between these 3 different situations.
In the host, it's possible to register a domain lifecycle callback with virConnectDomainEventRegisterAny(), and then if that callback is triggered because the guest shut down, the host can take action such as requesting a host shutdown. You'd have to supply the callback that does this (it would be a security issue if a guest action could shut down the host by default, without the use of a callback installed specifically for this reason).
Moreover, while rebooting a machine, an additional argument can be passed to reboot() syscall, which will be used by bootloader during the startup. Ideally, when calling e.g. "reboot recovery" inside an lxc container I'd like to be informed (inside host) that "reboot" was called with "recovery" as additional argument, so I can take appropriate actions.
Right now, this level of detail is not wired up. However, the callback signature does support a reason field, so you are welcome to write a libvirt patch that adds a new reason field and figures how to wire a guest recovery reboot into reporting a different reason than the default. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org