[DRBD-user] drbd-overview fix to display multiple drbd devices in single kvm virtual host

[Lars Ellenberg]

On Mon, May 20, 2013 at 10:48:00AM +0300, Liutauras Adomaitis wrote:
> Hi there,
> 
> this is my first post. I would like to share my fix for drbd-overview perl
> script. The problem I am trying to solve is that if a KVM virtual machine
> is using 2 drbd devices, drbd-overview doesn't show second device as used
> by any virtual machine.
> Here is the output of original drbd-overview:
>   1:r0/0               Connected Primary/Secondary UpToDate/UpToDate A
> r-----
>   2:Antras-drbd0/0     Connected Secondary/Primary UpToDate/UpToDate A
> r----- _Antras    vda virtio
>   3:Svarainis-drbd0/0  Connected Primary/Secondary UpToDate/UpToDate A
> r----- *Svarainis vda virtio
>   4:Svarainis-drbd1/0  Connected Primary/Secondary UpToDate/UpToDate A
> r-----
> 
> Here is the patch I suggest:
> 
> --- ./drbd-overview.orig        2013-05-20 10:38:00.790616544 +0300
> +++ ./drbd-overview.new 2013-05-20 10:37:29.207518963 +0300
> @@ -216,7 +216,7 @@
>                 # parent
>                 $_ = <V>;
>                 close(V) or warn "virsh dumpxml exit code: $?\n";
> -               for (m{<disk\ [^>]*>.*</disk>}gs) {
> +               for (m{<disk\ [^>]*>.*?</disk>}gs) {

Thanks.
Looks "obviously correct" ;-)

>                         m{<source\ dev='/dev/drbd([^']+)'/>} or next;
>                         my $dev = $1;
>                         if ($dev !~ /^\d+$/) {
> 
> And here is the output fixed drbd-overview:
>   1:r0/0               Connected Primary/Secondary UpToDate/UpToDate A
> r-----
>   2:Antras-drbd0/0     Connected Secondary/Primary UpToDate/UpToDate A
> r----- _Antras    vda virtio
>   3:Svarainis-drbd0/0  Connected Primary/Secondary UpToDate/UpToDate A
> r----- *Svarainis vda virtio
>   4:Svarainis-drbd1/0  Connected Primary/Secondary UpToDate/UpToDate A
> r----- *Svarainis vdb virtio
> 
> Notice the 4th line. Previously it didn't provide any associations with
> virtual machines, now it provides correct one.
> I am not a perl expert, nor even a beginner, so feel free to improve the
> fix. Didn't test it more extensively, so don't know what it will show with
> different virsh configs.
> 
> Regards,
> Liutauras


-- 
: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com