[pve-devel] [PATCH qemu-server 3/4] fix #2493: show QEMU errors in migration log

[Thomas Lamprecht]

On 12/9/19 4:14 PM, Stefan Reiter wrote:
> QEMU usually only prints warnings and errors and stays silent otherwise,
> so it makes sense to just log all of it's output.
> 
> Prefix it with '[<target_hostname>]' to indicate that the output is
> coming from the remote node, so users know where to search for the
> error.
> 
> Side effect is that the 'VM start' task created by the migration will
> now show the "QEMU:" prefix, but it's still very readable IMHO.
> 
> Signed-off-by: Stefan Reiter <s.reiter at proxmox.com>
> ---
>  PVE/QemuMigrate.pm |  4 +++-
>  PVE/QemuServer.pm  | 12 ++++++++++++
>  2 files changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/PVE/QemuMigrate.pm b/PVE/QemuMigrate.pm
> index b5ec45c..0353458 100644
> --- a/PVE/QemuMigrate.pm
> +++ b/PVE/QemuMigrate.pm
> @@ -625,10 +625,12 @@ sub phase2 {
>  	    $self->{target_drive}->{$targetdrive}->{volid} = $volid;
>  	    $self->{target_drive}->{$targetdrive}->{nbd_uri} = $nbd_uri;
>  
> +	} elsif ($line =~ m/^QEMU: (.*)$/) {
> +	    $self->log('info', "[$self->{node}] $1\n");
>  	}
>      }, errfunc => sub {
>  	my $line = shift;
> -	$self->log('info', $line);
> +	$self->log('info', "[$self->{node}] $line");
>      }, noerr => 1);
>  
>      die "remote command failed with exit code $exitcode\n" if $exitcode;
> diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
> index 01b677b..4317516 100644
> --- a/PVE/QemuServer.pm
> +++ b/PVE/QemuServer.pm
> @@ -5402,6 +5402,18 @@ sub vm_start {
>  	    noerr => 1,
>  	);
>  
> +	# when migrating, prefix QEMU output so other side can pick up any
> +	# errors that might occur and show the user
> +	if ($migratedfrom) {
> +	    $run_params{quiet} = 1;
> +	    $run_params{logfunc} = sub {
> +		my $msg = shift;
> +		return if !$msg;

$msg is always defined, and you want to print it too, if it's (why ever) '0'
or other false-y values.

> +		chomp $msg;

already done by run_command, FWIW, the whole log func could have been
reduced to:
$run_params{logfunc} = sub { print "QEMU: $_[0]\n" }

> +		print "QEMU: $msg\n";
> +	    };
> +	}
> +
>  	my %properties = (
>  	    Slice => 'qemu.slice',
>  	    KillMode => 'none',
>