[pve-devel] applied-series: [PATCH v2 0/7] Handle guest shutdown during backups

[Thomas Lamprecht <t.lamprecht@proxmox.com>]

On 19.10.20 14:18, Stefan Reiter wrote:
> Use QEMU's -no-shutdown argument so the QEMU instance stays alive even if the
> guest shuts down. This allows running backups to continue.
> 
> To handle cleanup of QEMU processes, this series extends the qmeventd to handle
> SHUTDOWN events not just for detecting guest triggered shutdowns, but also to
> clean the QEMU process via SIGTERM (which quits it even with -no-shutdown
> enabled).
> 
> A VZDump instance can then signal qmeventd (via the /var/run/qmeventd.sock) to
> keep alive certain VM processes if they're backing up, and once the backup is
> done, they close their connection to the socket, and qmeventd knows that it can
> now safely kill the VM (as long as the guest hasn't booted again, which is
> possible with some changes to the vm_start code also done in this series).
> 
> This series requires a lot of testing, since there can be quite a few edge cases
> lounging around. So far it's been doing well for me, aside from the VNC GUI
> looking a bit confused when you do the 'shutdown during backup' motion (i.e. the
> last image from the framebuffer stays in the VNC window, looks more like the
> guest has crashed than shut down) - but I haven't found a solution for that.
> 
> 
> v2:
> * use a pidfd (see `man pidfd_open`, though the manpage does not seem to be
>   available on Debian atm - I suppose since they don't support kernel 5.3 yet?),
>   fall back to regular racy kill() included, for people running older kernels
> * initialize client->type with CLIENT_NONE instead of client->state
> * rebase on latest master
> 
> 
> qemu-server: Stefan Reiter (6):
>   qmeventd: add handling for -no-shutdown QEMU instances
>   qmeventd: add last-ditch effort SIGKILL cleanup
>   vzdump: connect to qmeventd for duration of backup
>   vzdump: use dirty bitmap for not running VMs too
>   config_to_command: use -no-shutdown option
>   fix vm_resume and allow vm_start with QMP status 'shutdown'


applied series, thanks!

As talked off-list, may make sense to also disable the shutdown button for running backups,
as the user cannot use that to stop the backup, but rather should use the "stop" button
of the backup worker task, if they want to do that.