[ovs-dev] [PATCH 14/18] keep "kernel name" for each netdev

YAMAMOTO Takashi yamamoto at valinux.co.jp
Fri Feb 1 03:23:00 UTC 2013


hi,

>> >         * ovs-vswitchd starts up and creates some tap devices.  It knows
>> >           the mapping between the user-requested name and the kernel
>> >           name.
>> > 
>> >         * Admin restarts ovs-vswitchd.
>> > 
>> >         * New instance of ovs-vswitchd creates new tap devices because
>> >           it does not know the kernel names of the existing ones and
>> >           does not have a way to discover them.  The existing ones are
>> >           effectively leaked.
>> 
>> there isn't a leak as ovs-vswitchd destroys the old one when stopping.
> 
> OK.  But this may cause a different inconvenience to the user: if the
> user configured an IP address on the tap device, then restarting
> ovs-vswitchd will drop that IP address and the user will have to add it
> back.  This doesn't happen with the Linux kernel datapath, and I don't
> think it happens with the Linux userspace datapath (I can't say for the
> FreeBSD one).  But if that issue does not bother you, then I will not
> worry about it.

are you sure about the linux userspace datapath behaviour?
a casual looking at linux's Documentation/networking/tuntap.txt and
netdev-linux.c made me think otherwise.

YAMAMOTO Takashi



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