[pve-devel] applied: [PATCH v2 pve-common] Network : veth pair : fix mtu

Wolfgang Bumiller w.bumiller at proxmox.com
Thu Nov 22 10:29:34 CET 2018


applied, thanks

On Wed, Nov 21, 2018 at 05:34:29PM +0100, Alexandre Derumier wrote:
> The ip link set command which create the veth pair is not setting mtu on both peers
> 
> example:
> vm 106 is on a bridge with mtu 9000
> 
> 222: tap160i1: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 9000 qdisc pfifo_fast master fwbr160i1 state UNKNOWN group default qlen 1000
> 223: fwbr160i1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
> 224: fwpr160p1 at fwln160i1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000 qdisc noqueue state UP group default qlen 1000
> 225: fwln160i1 at fwpr160p1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
> 
> fwpr160p1 at fwln160i1 is correctly created with mtu 9000
> but
> fwln160i1 at fwpr160p1 is created with mtu 1500.
> (and then vmbr106i1 is lowered to 1500 too).
> 
> This is doing network problem, as tap160i1 is mtu9000.
> 
> After this patch:
> 
> 222: tap160i1: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 9000 qdisc pfifo_fast master fwbr160i1 state UNKNOWN group default qlen 1000
> 223: fwbr160i1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000 qdisc noqueue state UP group default qlen 1000
> 224: fwpr160p1 at fwln160i1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000 qdisc noqueue state UP group default qlen 1000
> 225: fwln160i1 at fwpr160p1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000 qdisc noqueue state UP group default qlen 1000
> ---
>  src/PVE/Network.pm | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/src/PVE/Network.pm b/src/PVE/Network.pm
> index 3421532..8dfc9c2 100644
> --- a/src/PVE/Network.pm
> +++ b/src/PVE/Network.pm
> @@ -291,7 +291,7 @@ sub veth_create {
>  
>      # create veth pair
>      if (! -d "/sys/class/net/$veth") {
> -	my $cmd = "/sbin/ip link add name $veth type veth peer name $vethpeer mtu $bridgemtu";
> +	my $cmd = "/sbin/ip link add name $veth mtu $bridgemtu type veth peer name $vethpeer mtu $bridgemtu";
>  	$cmd .= " addr $mac" if $mac;
>  	system($cmd) == 0 || die "can't create interface $veth\n";
>      }
> -- 
> 2.11.0




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