[pve-devel] applied: [PATCH container] use the lxc@ service file provded by lxc

[Wolfgang Bumiller]

On Thu, Feb 02, 2017 at 11:21:38AM +0100, Wolfgang Bumiller wrote:
> Until now the lxc-start process was sort of a danglign
> process in the pvedaemon.service cgroup when a container was
> started from the web UI causing long stalls when trying to
> restart pvedaemon and potential container kills. (Mostly
> problematic when issuing package upgrades).
> We now start containers via the lxc@ service file giving
> them their own service cgroup.
> 
> The downside is that we'll have to patch the lxc@ service
> file in the lxc package to Type=forking without the -F
> option otherwise all of the the containers' console outputs
> will end up in the logs...
> ---
> The upside is that we get to kill that whole forking mess in
> the post-stop hook and can just use systemctl --no-block restart lxc at vmid
> (after updating the lxc config of course)
> 
>  src/PVE/API2/LXC/Status.pm |  2 +-
>  src/PVE/VZDump/LXC.pm      |  2 +-
>  src/lxc-pve-poststop-hook  | 21 +++++++--------------
>  3 files changed, 9 insertions(+), 16 deletions(-)
> 
> diff --git a/src/PVE/API2/LXC/Status.pm b/src/PVE/API2/LXC/Status.pm
> index 8c389f7..a3d11f1 100644
> --- a/src/PVE/API2/LXC/Status.pm
> +++ b/src/PVE/API2/LXC/Status.pm
> @@ -178,7 +178,7 @@ __PACKAGE__->register_method({
>  
>  		    local $ENV{PVE_SKIPLOCK}=1 if $skiplock;
>  
> -		    my $cmd = ['lxc-start', '-n', $vmid];
> +		    my $cmd = ['systemctl', 'start', "lxc\@$vmid"];
>  
>  		    run_command($cmd);
>  
> diff --git a/src/PVE/VZDump/LXC.pm b/src/PVE/VZDump/LXC.pm
> index 0d871a1..fafffc6 100644
> --- a/src/PVE/VZDump/LXC.pm
> +++ b/src/PVE/VZDump/LXC.pm
> @@ -260,7 +260,7 @@ sub stop_vm {
>  sub start_vm {
>      my ($self, $task, $vmid) = @_;
>  
> -    $self->cmd ("lxc-start -n $vmid");
> +    $self->cmd(['systemctl', 'start', "lxc\@$vmid"]);
>  }
>  
>  sub suspend_vm {
> diff --git a/src/lxc-pve-poststop-hook b/src/lxc-pve-poststop-hook
> index b8524cc..a4302d6 100755
> --- a/src/lxc-pve-poststop-hook
> +++ b/src/lxc-pve-poststop-hook
> @@ -74,21 +74,14 @@ __PACKAGE__->register_method ({
>  
>  	my $target = $ENV{LXC_TARGET};
>  	if ($target && $target eq 'reboot') {
> -	    # in order to make sure hot-plugged config changes aren't reverted
> +	    # In order to make sure hot-plugged config changes aren't reverted
>  	    # to what the monitor initially loaded we need to stop the container
> -	    # and restart it
> -	    local $SIG{HUP} = 'IGNORE';
> -	    my $pid = fork();
> -	    die "fork failed during container reboot: $!\n" if !defined($pid);
> -	    if (!$pid) {
> -		POSIX::setsid();
> -		close STDIN;
> -		close STDOUT;
> -		close STDERR;
> -		PVE::LXC::update_lxc_config($vmid, $conf);
> -		exec {'lxc-start'} 'lxc-start', '-n', $vmid
> -		or POSIX::_exit(-1);
> -	    }
> +	    # and restart it.
> +	    # Update the config and queue a restart of the lxc@$vmid task, note
> +	    # that we must not block because we're part of the service cgroup
> +	    # systemd waits for to die before issuing the new lxc-start command.
> +	    PVE::LXC::update_lxc_config($vmid, $conf);
> +	    PVE::Tools::run_command(['systemctl', '--no-block', 'restart', "lxc\@$vmid"]);
>  	    # cause lxc to stop instead of rebooting
>  	    POSIX::_exit(1);
>  	}
> -- 
> 2.1.4