[pve-devel] [PATCH container 1/6] add reboot helpers to be used by containers

[Stefan Reiter]

On 11/12/19 5:26 PM, Oguz Bektas wrote:
> code for create_reboot_request and clear_reboot_request is from qemu, the only
> difference is that we use /run/lxc/$vmid.reboot path instead of
> /run/qemu-server.
> 
> there _is_ actually reboot triggers for lxc which are used by the
> prestart hook and similar, however i think it's better if we can
> differentiate between reboot requests from inside the container and from
> API. (inadvertently this also allows to reboot container from inside without
> applying pending changes)
> 
> since we don't have to clean up like in qemu, we can simply run vm_stop
> and vm_start for a reboot operation.
> 

That being so, why do we need a restart trigger file at all? You create 
it in vm_reboot and then delete it in vm_start or the error path... But 
it existing or not doesn't change behaviour of any of these?

> Signed-off-by: Oguz Bektas <o.bektas at proxmox.com>
> ---
>   src/PVE/LXC.pm | 41 +++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 41 insertions(+)
> 
> diff --git a/src/PVE/LXC.pm b/src/PVE/LXC.pm
> index cdf6d64..c77ee01 100644
> --- a/src/PVE/LXC.pm
> +++ b/src/PVE/LXC.pm
> @@ -2013,6 +2013,47 @@ sub vm_stop {
>       die "container did not stop\n";
>   }
>   
> +sub create_reboot_request {
> +    my ($vmid) = @_;
> +    open(my $fh, '>', "/run/lxc/$vmid.reboot")
> +	or die "failed to create reboot trigger file: $!\n";
> +    close($fh);
> +}
> +
> +sub clear_reboot_request {
> +    my ($vmid) = @_;
> +    my $path = "/run/lxc/$vmid.reboot";
> +    my $res = 0;
> +
> +    if (-e $path) {
> +	$res = unlink($path);
> +	die "could not remove reboot request for $vmid: $!\n" if !$res;
> +    }
> +
> +    return $res;
> +}
> +
> +sub vm_reboot {
> +    my ($vmid, $timeout, $skiplock) = @_;
> +
> +    PVE::LXC::Config->lock_config($vmid, sub {
> +	eval {
> +	    return if !check_running($vmid);
> +
> +	    create_reboot_request($vmid);
> +	    vm_stop($vmid, 0, $timeout, 1); # kill if timeout exceeds
> +
> +	    my $conf = PVE::LXC::Config->load_config($vmid);
> +	    vm_start($vmid, $conf);
> +	};
> +	if (my $err = $@) {
> +	    # avoid that the next normal shutdown will be confused for a reboot
> +	    clear_reboot_request($vmid);
> +	    die $err;
> +	}
> +    });
> +}
> +
>   sub run_unshared {
>       my ($code) = @_;
>   
>