[systemd-devel] [SOLVED] Re: [networkd] Set MTU of disconnected OVS bridge

[Ian Pilcher]

On 04/01/2016 05:04 AM, Lennart Poettering wrote:
> On Thu, 24.03.16 09:52, Ian Pilcher (arequipeno at gmail.com) wrote:
>
>> I have a "disconnected" Open vSwitch on my system named ovs1.  By
>> "disconnected" I mean that it is not connected to any physical
>> interface, bond, etc.; it exists only for inter-VM communication.
>>
>> I just discovered that jumbo frames (anything larger than 1528 bytes)
>> are being dropped when traveling across the bridge.  I need to set the
>> MTU of the bridge (actually its internal port) to a larger value.
>>
>> I haven't been able to figure out a way to get systemd-networkd to do
>> this.  I tried creating /etc/systemd/network/ovs1.link, but it had no
>> effect:
>>
>>    [Match]
>>    OriginalName=ovs1
>>
>>    [Link]
>>    MTUBytes=9000
>
> Does "networkctl status" on the interface show that the .link file got
> applied?

I figured it out.  99-default.link is lexically earlier than ovs1.link,
so my link file was never used.  Changing the name to 98-ovs1.link makes
it work.

I'm a bit embarrassed by this.  OTOH, I don't consider myself to be
overly stupid, and this is probably the 3rd or 4th time that I've been
bitten by this.  (About once a year or so, just long enough for me to
forget.)

Using ${INTERFACE}.link as the name of a link file is a very natural
thing to do, and the current setup ensures that this will never work.

Has changing 99-default.link to something like ZZZZ-default.link ever
been considered?

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