> -----Original Message----- > From: Paolo Bonzini <pbonz...@redhat.com> > Sent: Tuesday, October 22, 2019 1:24 AM > To: Zhang, Chen <chen.zh...@intel.com>; Jason Wang > <jasow...@redhat.com>; qemu-dev <qemu-devel@nongnu.org> > Cc: Zhang Chen <zhangc...@gmail.com> > Subject: Re: [RFC PATCH 1/4] net/awd.c: Introduce Advanced Watch Dog > module framework > > On 16/10/19 13:22, Zhang Chen wrote: > > From: Zhang Chen <chen.zh...@intel.com> > > > > This patch introduce a new module named Advanced Watch Dog, and > > defined the input and output parameter. AWD use standard chardev as > > the way of communicationg with the outside world. Demo command: > > -object > > advanced- > watchdog,id=heart1,server=on,awd_node=h1,notification_node=he > > artbeat0,opt_script=opt_script_path,iothread=iothread1,pulse_interval= > > 1000,timeout=5000 > Is there a standard or specification for how to interact with this? Is this > something that was developed explicitly for these patches, or did it exist > before? >
Hi Paolo, Thanks you for your attention. Current AWD patch just accept any input as the signal to refresh the watchdog timer, and we can also make a certain interactive protocol here. For the output user can pre-write some command or some messages in the AWD opt-script. We noticed that there is no way for VMM communicate directly, maybe some people think we don't need such things(up layer software like openstack can handle it). But we engaged with real customer found that in some cases, they need a lightweight and efficient mechanism to solve some practical problems(openstack is too heavy). For example in COLO (https://wiki.qemu.org/Features/COLO). We need heartbeat service to detect two node status, current implement need another application running in the host to do this job, if found issue it will send message to local Qemu by qmp command, This is very complicated in actual scenarios, we have to bind each heartbeat service with the VM instance and handle lots of internal errors. Advanced watch dog can solve this issue in most cases. At the same time, AWD also can be used in a variety of scenarios, it can active detect Qemu status and do some simple automatic processing for example kill itself when it loss control with openstack(just need simple paired service). Thanks Zhang Chen > Paolo