RE: [PATCH V4 0/5] Introduce Advanced Watch Dog module

["Zhang, Chen" <chen.zhang@intel.com>]

> -----Original Message-----
> From: Jason Wang <jasowang@redhat.com>
> Sent: Monday, January 20, 2020 10:57 AM
> To: Zhang, Chen <chen.zhang@intel.com>; Paolo Bonzini
> <pbonzini@redhat.com>; Philippe Mathieu-Daudé <philmd@redhat.com>;
> qemu-dev <qemu-devel@nongnu.org>
> Cc: Zhang Chen <zhangckid@gmail.com>
> Subject: Re: [PATCH V4 0/5] Introduce Advanced Watch Dog module
> 
> 
> On 2020/1/19 下午5:10, Zhang, Chen wrote:
> > Hi~
> >
> > Anyone have comments about this module?
> 
> 
> Hi Chen:
> 
> I will take a look at this series.

Sorry for slow reply due to CNY and extend leave.
OK, waiting your comments~ Thanks~

> 
> Two general questions:
> 
> - if it can detect more than network stall, it should not belong to /net

This module use network connection status to detect all the issue(Host to Guest/Host to Host/Host to Admin...).
The target is more than network but all use network way. So it is looks a tricky problem.

> - need to convince libvirt guys for this proposal, since usually it's the duty of
> upper layer instead of qemu itself
> 

Yes, It looks a upper layer responsibility, but In the cover latter I have explained the reason why we need this in Qemu.
 try to make this module as simple as possible. This module give upper layer software a new way to connect/monitoring Qemu.
And due to all the COLO code implement in Qemu side, Many customer want to use this FT solution without other dependencies,
it is very easy to integrated to real product. 

Thanks
Zhang Chen

> Thanks
> 
> 
> > We have some clients already try to use this module with COLO. Please
> review this part.
> > If no one want to maintain this module, I can maintain this module myself.
> >
> > Thanks
> > Zhang Chen
> >
> >> -----Original Message-----
> >> From: Qemu-devel <qemu-devel-
> >> bounces+chen.zhang=intel.com@nongnu.org> On Behalf Of Zhang, Chen
> >> Sent: Tuesday, January 7, 2020 12:33 PM
> >> To: Jason Wang <jasowang@redhat.com>; Paolo Bonzini
> >> <pbonzini@redhat.com>; Philippe Mathieu-Daudé
> <philmd@redhat.com>;
> >> qemu-dev <qemu-devel@nongnu.org>
> >> Cc: Zhang Chen <zhangckid@gmail.com>
> >> Subject: Re: [PATCH V4 0/5] Introduce Advanced Watch Dog module
> >>
> >> Hi All,
> >>
> >> No news for a while about this series.
> >>
> >> This version already add new docs to address Paolo's comments.
> >>
> >> Please give me more comments.
> >>
> >>
> >> Thanks
> >>
> >> Zhang Chen
> >>
> >>
> >> On 12/17/2019 8:45 PM, Zhang, Chen wrote:
> >>> From: Zhang Chen <chen.zhang@intel.com>
> >>>
> >>> Advanced Watch Dog is an universal monitoring module on VMM side, it
> >>> can be used to detect network down(VMM to guest, VMM to VMM,
> VMM
> >> to
> >>> another remote server) and do previously set operation. 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 outputs, 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). so we engaged with real
> >>> customer found that they need a lightweight and efficient mechanism
> >>> to solve some practical problems,
> >>>
> >>> For example Edge Computing cases(they think high level software is
> >>> too heavy to use in Edge or it is hard to manage and combine with VM
> instance).
> >>> It make user have basic VM/Host network monitoring tools and basic
> >>> false tolerance and recovery solution..
> >>>
> >>> Please see the detail documentation in the last patch.
> >>>
> >>> V4:
> >>>    - Add more introduction in qemu-options.hx
> >>>    - Addressed Paolo's comments add docs/awd.txt for the AWD module
> >> detail.
> >>> V3:
> >>>    - Rebased on Qemu 4.2.0-rc1 code.
> >>>    - Fix commit message issue.
> >>>
> >>> V2:
> >>>    - Addressed Philippe comments add configure selector for AWD.
> >>>
> >>> Initial:
> >>>    - Initial version.
> >>>
> >>>
> >>> Zhang Chen (5):
> >>>     net/awd.c: Introduce Advanced Watch Dog module framework
> >>>     net/awd.c: Initailize input/output chardev
> >>>     net/awd.c: Load advanced watch dog worker thread job
> >>>     vl.c: Make Advanced Watch Dog delayed initialization
> >>>     docs/awd.txt: Add doc to introduce Advanced WatchDog(AWD)
> module
> >>>
> >>>    configure         |   9 +
> >>>    docs/awd.txt      |  88 +++++++++
> >>>    net/Makefile.objs |   1 +
> >>>    net/awd.c         | 491
> >> ++++++++++++++++++++++++++++++++++++++++++++++
> >>>    qemu-options.hx   |  20 ++
> >>>    vl.c              |   7 +
> >>>    6 files changed, 616 insertions(+)
> >>>    create mode 100644 docs/awd.txt
> >>>    create mode 100644 net/awd.c
> >>>