[systemd-devel] [networkd] Unable to set MTU with .link file

[Ian Pilcher]

On 06/08/2017 11:03 PM, Ian Pilcher wrote:
> I am tearing my hair out trying to figure out why I an unable to set the
> MTU of an OVS port with a .link file.

Replying to myself for posterity ...

As so often seems to be the case, my difficulties were due to that
recurring issue, "You're doing it wrong."

TL;DR - Setting different MTUs on different ports of an OVS bridge
doesn't work as expected, so using separate tagged ports on the host OS
isn't the way to go.

Instead, create VLAN netdevs on top of the trunked OVS port (treating
it as if it were a physical interface or bond).  For example:

98-ovs0.link:

     [Match]
     OriginalName=ovs0

     [Link]
     MTUBytes=8996

ovs0.network:

     [Match]
     Name=ovs0

     [Network]
     VLAN=ovs0.248
     VLAN=ovs0.250

ovs0.248.netdev:

     [NetDev]
     Name=ovs0.248
     Kind=vlan

     [VLAN]
     Id=248

ovs0.250.netdev:

     [NetDev] 

     Name=ovs0.250 

     Kind=vlan 

     MTUBytes=1500 

 

     [VLAN] 

     Id=250

-- 
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Ian Pilcher                                         arequipeno at gmail.com
-------- "I grew up before Mark Zuckerberg invented friendship" --------
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