Re: [Qemu-devel] [PATCH] os-posix: call system_powerdown on SIGTERM, enabling clean guest shutdown

[Anthony Liguori <anthony@codemonkey.ws>]

On 11/03/2011 08:08 AM, Bjørn Mork wrote:
> Allow well behaved guests to shutdown cleanly when we receive SIGTERM,
> e.g. when the host reboots.
>
> The host may be powered down or rebooted while guests are running
> without any outer supervision scripts.  These guests will be stopped
> by the generic host "sendsigs" script, usually by sending SIGTERM to all
> processes still running and then SIGKILL if that didn't work.  Let the
> guest power down instead of just killing i instantly.
>
> Signed-off-by: Bjørn Mork<bjorn@mork.no>

I don't think this is such a good idea.  SIGTERM shouldn't be subject to the 
guest's interpretations.

Instead of doing a killall qemu, just send a system_powerdown command to each 
qemu's monitor instance.

Regards,

Anthony Liguori

> ---
> I wonder if I miss something obvious here... So this patch should be
> considered a RFC.  It certainly fixes a small problem for me:  I often
> run a number of guests which are started manually, or by simple "runme"
> scripts, without any libvirt wrapper or similar.  If/when the host is
> rebooted, these guests will be shut down abrubtly with possible guest
> file system corruption and other data loss as a consequence. Powering
> down on SIGTERM seems like an obious win-win.
>
> I also wonder if it would be useful to do a reboot on HUP, but that
> wouldn't solve any real problem so I'm not including it in this
> patch.
>
>
>
> Bjørn
>
>   os-posix.c |    5 ++++-
>   1 files changed, 4 insertions(+), 1 deletions(-)
>
> diff --git a/os-posix.c b/os-posix.c
> index dbf3b24..167fd3b 100644
> --- a/os-posix.c
> +++ b/os-posix.c
> @@ -65,7 +65,10 @@ void os_setup_early_signal_handling(void)
>
>   static void termsig_handler(int signal, siginfo_t *info, void *c)
>   {
> -    qemu_system_killed(info->si_signo, info->si_pid);
> +    if (info->si_signo == SIGTERM)
> +	qemu_system_powerdown_request();
> +    else
> +	qemu_system_killed(info->si_signo, info->si_pid);
>   }
>
>   void os_setup_signal_handling(void)