When is a switch not a switch?

[Paul Vixie]

D'Arcy Cain wrote on 2020-10-22 07:03:
> On 10/21/20 11:16 PM, Jason Tubnor wrote:
>>     public: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric
>> 0 mtu 1500
>>       ...
>>               groups: bridge
>>               nd6 options=9<PERFORMNUD,IFDISABLED>
>>     tap0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0
>> mtu 1500
>> ...
>>               groups: tap vm-port
>>               media: Ethernet autoselect
>>               ...
>>
>>
>> tap0 is not a member of public so has no way to get to eth0 or public.
>
> Odd.  I thought that vm-bhyve did that when the VM came up.

here's how i do it, per years-ago documentation to this effect:

> autobridge_interfaces="bridge0"                                                                                        
> autobridge_bridge0="tap*
> igb1"                                                                                         
> ifconfig_igb1="up media 1000baseTX fib
> 1"                                                                              
> cloned_interfaces="bridge0 tap0 tap1 tap2 tap3 tap4 tap5 tap6 tap7"
> ifconfig_bridge0="inet 24.104.150.210/27 fib
> 1"                                                                        
> ifconfig_bridge0_ipv6="inet6 2001:559:8000:cd::2/64 fib 1
> auto_linklocal up"
> ifconfig_tap0="up fib 1"
> ifconfig_tap1="up fib 1"
> ifconfig_tap2="up fib 1"
> ifconfig_tap3="up fib 1"
> ifconfig_tap4="up fib 1"
> ifconfig_tap5="up fib 1"
> ifconfig_tap6="up fib 1"
> ifconfig_tap7="up fib 1"

note, fib 1 is a detail here, just gives me a different default route
for the virtual machines.


>
> Hmm.  It looks like tap0 gets attached to vm-public if it is
> configured to attach to public.  Perhaps I just need to name the
> bridge that way.

autobridge_* (rc.conf(5)) is what you'll need for that.

>
>> I'd avoid creating the 'public' bridge and let vm-bhyve create it. 
>> Something like:
>>
>> vm switch create public
>> vm switch add public eth0
>
> But then I can't create the IP on the host until too late in the
> boot.  I assume that you mean to do that in rc.local.  Are you sure
> that the above is any different than what I did?

because my management interface for the milking machine is on a
different subnet, i have this:

> vlans_igb0="201 203"
> ifconfig_igb0="up vlanmtu media
> 1000baseTX"                                                                            
> ifconfig_igb0_201="inet
> 24.104.150.130/26"                                                                             
> ifconfig_igb0_201_ipv6="inet6 2001:559:8000:c9::3/64"
> ifconfig_igb0_203="inet
> 24.104.150.16/27"                                                                              
> ifconfig_igb0_203_ipv6="inet6 2001:559:8000:cb::16/64"


however, you could do away with that and just autobridge your connected
interface (mine is igb1, see above.)

>
>> Then for the guest:
>>
>> vm add -d network -s public <guestname>
>
> Hard to automate when VM can migrate to another host.

hard to do any of this if you're not doing it by hand. (i don't use the
"vm" command.)

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